Vox Meditantis

Michiyo Tsujimura (1888–1969) stands as one of modern science’s most decisive chemical minds, yet her name remains virtually unknown beyond Japanese academic circles – a silence that contradicts the global reach of her discoveries. Working without salary, formal university status, or institutional recognition during Japan’s most turbulent decades, she identified vitamin C in green tea, then became the first scientist worldwide to isolate catechin, opening an entire field of tea chemistry that still yields findings today. Her story is not one of quiet persistence, but of deliberate, exacting scientific reasoning applied with extraordinary tenacity under conditions that would have stopped most researchers entirely.

Dr. Tsujimura, thank you for joining us today. I’d like to begin with your earliest memory of science – something that set you on this path. What was it?

You know, it was not a grand moment. I was perhaps seven or eight, and my father – he was involved in agricultural administration – brought home specimens of different soil types from various prefectures. He laid them out in small glass jars and showed me how their colour changed when water was added. Some turned darker, some almost orange-red. He told me that the colour itself was a kind of information, that chemistry was simply asking questions of matter and listening to what it revealed.

That idea stayed with me: chemistry as a conversation. Not as something imposed upon nature, but discovered through careful observation.

That’s a beautiful frame. Did you have formal education?

Formal? Yes and no. My family was progressive enough to value education for daughters, which was unusual then. I attended the Higher Women’s Normal School in Tokyo – this was our pathway, you understand. We were trained as educators, not as researchers. The assumption was that women’s scientific knowledge would be deployed in teaching, not in original investigation.

But I was fortunate. At the normal school, I studied chemistry under exceptionally rigorous instructors who treated our minds as capable of genuine scientific reasoning. One teacher, Chika Kuroda, was herself a graduate of Tokyo Imperial University – one of the first women permitted to study there, though only after finishing her degree and joining as a research student. She had navigated these spaces before me. She showed me it was possible, even if the path was not… well, it was not welcoming.

When you finished your studies, what happened next?

I taught at the normal school for some years. But teaching, whilst valuable, was not where my mind lived. I wanted to perform chemistry myself, not simply convey it. In 1920, I was invited to Hokkaido Imperial University by my mentor Kono Yasui, to work in the Food Nutritional Laboratory of the Agricultural Chemistry Department.

They could not make me a student – women were not admitted. And they would not pay me. So I became an “unpaid assistant.” That phrase – it obscures what one actually does, does it not? I was conducting original research in nutritional analysis, developing protocols, recording data, formulating hypotheses. But the language around it made me invisible.

How did that manifest in your day-to-day work?

I had no office. No desk with my name. I arrived each morning and worked in whatever corner of the laboratory was available. I had no budget line, so I had to be extraordinarily careful with materials – I could not afford failure. Every experiment had to be designed with precision because I could not repeat it if I wasted reagents. Ironically, this forced efficiency made my technical work quite refined. One learns speed and economy when there is no margin for error.

I was also not listed on preliminary results or announcements. If a visiting researcher came through, I would be introduced as “the assistant helping with the work,” not as the researcher who designed the protocol. And when results were promising, I might learn secondhand that they had been presented at a seminar. It was peculiar – you are advancing knowledge, but the knowledge bearer is not quite you.

But I was inside the laboratory. That was what mattered to me then.

In 1923, the Great Kanto Earthquake destroyed much of Tokyo and Yokohama. You were at Tokyo Imperial University by then. What happened to your research?

The earthquake struck at 11:58 in the morning. The laboratory where I was working simply… collapsed. It was not dramatic in the way one might imagine – not a single catastrophic failure, but a series of violent, sustained movements that turned brick and timber into rubble. We understood very quickly that we had to leave, that staying meant being buried.

I remember Umetaro Suzuki, my supervisor, calling out to gather whatever we could. I went to my workstation and took what I had in front of me – my precision scales, my notebooks with the week’s observations. The scales were the irreplaceable items. In Japan, good analytical balances were expensive and difficult to procure. I held them and ran.

The fires came afterward. The entire city was alight. Over 100,000 people died in those hours and days. I knew people who were lost. The laboratory itself was completely destroyed. All the equipment we could not carry – gone.

 How long until you could resume research?

Perhaps three months. RIKEN – the Institute of Physical and Chemical Research – offered me a position as a researcher. Not an unpaid assistant, you understand. A researcher. It was 1924. I was 36 years old, and for the first time, I had an institutional identity in science and a modest salary. I had also, finally, a laboratory space of my own.

That is when the vitamin C work began, in collaboration with Seitaro Miura. We wanted to understand the chemical basis of green tea’s nutritional properties. There were claims in traditional knowledge that tea was healthful, but no rigorous chemical explanation. What exactly in the leaf was conferring these benefits?

Walk me through the methodology. How did you approach the problem?

First, extraction. We took dried green tea leaves and treated them with hot water – essentially what one does when brewing tea, but under controlled conditions. We varied the temperature, the duration of contact, and the ratio of leaf to water to understand which compounds were being released. We used organic solvents as well – ethanol, methanol – to see which extraction medium yielded different chemical profiles.

Our working hypothesis was that the nutritive value likely resided in water-soluble components. So we focused on aqueous extractions initially.

Once we had the extract, we concentrated it by evaporation – slowly, under mild heat, to avoid degrading heat-sensitive compounds. Then came the critical step: separation and identification.

How did you separate one compound from another?

We used fractional crystallisation – a process one must understand very deeply to execute well. As you cool a concentrated solution of mixed compounds, different substances precipitate out of solution at different temperatures. By controlling the temperature very precisely and filtering at specific points, you can separate compounds by their differing solubility profiles.

This was not trivial work. You must have sensitivity to when crystallisation begins, when it is complete. We also employed paper chromatography when it became available – allowing us to see how many distinct compounds were present in our extracts by their differential migration through the paper.

We tested the isolated fractions for vitamin C using standard bioassays and chemical colour reactions. The Tillmans reagent was particularly useful – it produces a characteristic colour change in the presence of ascorbic acid. We found that the vitamin C concentration in green tea was substantially higher than in other food plants we tested as controls.

What were the actual quantities?

In fresh green tea leaves, we identified approximately 250 to 300 milligrams of vitamin C per 100 grams of fresh leaf material. When the leaves were dried – the standard form for export and consumption – the concentration became more concentrated by weight, though some loss occurred during the drying process itself. These were significant figures. For comparison, the vitamin C content in fresh citrus fruit was roughly similar, and many Western vegetables considerably lower.

What made this commercially and nutritionally important was that green tea represented a portable, shelf-stable source of the vitamin. You could dry it, ship it, store it for months, and it retained substantial potency. That was not true of fresh fruits or many vegetables.

And this was published in 1924?

Yes. In Japanese-language journals primarily, though the findings circulated through international scientific networks through abstracts and correspondence. The timing was fortuitous – and I do mean fortuitous, not planned. American physicians and nutritionists were becoming interested in vitamin supplementation. Scurvy was known, the importance of vitamin C was being recognised. And here was evidence that a beverage that was already traded internationally contained meaningful quantities of an essential nutrient.

Japan’s green tea exports to America increased considerably in the following years. Whether one could directly credit that increase to our publication, I cannot say with certainty. But the association was made. Our research gave scientific legitimacy to what had been understood in Japan for centuries through experience.

The catechin work came several years later. What prompted the shift in focus?

The vitamin C was important, but it was not surprising, chemically speaking. Vitamin C had already been identified in various plants. We had simply found it in tea and quantified it. Useful, but methodologically straightforward.

But the character of green tea – its astringency, its particular bitter taste, its colour, its effects on the human body – these properties were not explained by vitamin C alone. We knew something else was present. Something that gave green tea its distinctive properties.

That something was the puzzle that occupied me for years. What was the compound responsible for astringency? For the specific bitterness? What gave green tea its colour profile?

I began collaborating more intensively with colleagues in organic chemistry. We focused on the non-volatile components of tea leaves – the substances that remained after water had been evaporated. This residue was complex, containing dozens of distinct compounds. We needed to separate them methodically.

This is where crystallisation became even more crucial, yes?

Precisely. But crystallisation from such a complex mixture is far more challenging than from a relatively pure solution. You must have enormous patience and refined technique. The first step was to use fractional crystallisation with water as the solvent – adding water slowly to a concentrated extract and allowing crystals to form at specific temperatures.

We began to isolate needle-like crystals. These crystals had a yellowish tinge and a distinctly astringent taste. We tested them – and I must emphasise tested in the full chemical sense. We determined their melting point, their solubility in various solvents, their behaviour under heat. We performed combustion analysis to determine their elemental composition.

The molecular formula we derived for the primary catechin was C₁₅H₁₄O₆ – fifteen carbon atoms, fourteen hydrogen, six oxygen. That formula told us something about the compound’s structure, though it did not yet reveal the precise arrangement of atoms.

How did you determine the atomic structure?

This required synthesis and degradation studies – we did not have the spectroscopic techniques available today. We broke the molecule apart chemically, identified the fragments, and reasoned about how they must have been connected in the intact compound.

We used oxidative degradation – treating the catechin with oxidising agents and identifying what products emerged. Each oxidation product provided a clue about the original structure. We also synthesised related compounds and compared their properties to our natural product.

It was rather like solving a puzzle where you cannot see the complete picture at once, but must reason from the fragments and their relationships. By 1929, we had isolated and characterised epicatechin – one form of catechin. In 1930, we isolated tannin in crystalline form and determined its structure as C₂₂H₁₈O₁₀.

Then in 1934, we identified another variant – gallocatechin, 1-epigallocatechin.

What was the practical significance of distinguishing between these forms?

Tremendous, actually. They are not merely different names for the same thing. Each variant has subtly different chemical properties – different solubility profiles, different reactivity, different biological effects in the human body.

The distinction mattered for understanding how green tea functioned nutritionally and pharmacologically. If you simply called all of these compounds “tea tannins,” you obscured the fact that green tea contains multiple structurally distinct compounds, each potentially contributing different effects.

This specificity also mattered for quality control and standardisation in the tea industry. Different processing methods – the temperature at which leaves were dried, the duration of oxidation, the timing of harvest – produced different ratios of these catechins. Understanding the chemistry allowed for informed decisions about processing.

I’m curious – did you have competitors pursuing similar isolations? Were others working on tea chemistry?

There were researchers in other countries investigating tea chemistry, yes. But the isolation of pure catechin crystals – determining their elemental composition and beginning to elucidate their structure – this required a very particular combination of organic chemistry expertise and access to tea as a starting material.

I will say this candidly: I was not aware at the time of any other laboratory that had successfully isolated catechin in crystalline form and performed the rigorous structural analysis we conducted. I learned after the fact that my claim to priority was not universally accepted in all scientific circles. Some Western chemists were sceptical that a woman researcher, working in Japan, had accomplished this ahead of more established laboratories in Europe or America.

I will not pretend this did not sting. But the crystals existed. The measurements were reproducible. The molecular formula was sound. Time vindicated the work.

That scepticism – how do you interpret it now?

I was a woman. I was Japanese. I published in Japanese journals. I worked at an institute that was not yet internationally prestigious in Western eyes. I had not trained at Oxford or Cambridge or the Sorbonne. Any one of those factors would have prompted caution from Western chemists. All of them together meant that some doubted not whether the work was sound, but whether it was truly mine.

That is the only charitable interpretation I can offer. That said, I also wonder if the early Western dismissal of our findings meant that the applications – the pharmaceutical potential, the industrial applications – were not pursued as vigorously in the West as they might have been. We understood what we had found. We understood its significance. But we were heard less loudly than we might have been.

In 1932, at age 43, you became the first woman in Japan to earn a doctorate in agriculture. But you achieved this without ever being formally admitted as a university student. Can you explain how that was possible?

The system was absurd, truly. I had been conducting research for over a decade – original, published research that was being cited by other scientists. Yet I held no degree, no formal credentials. I could lecture? No. Could I supervise students? No. Could I apply for grants as a principal investigator? Questionable.

Tokyo Imperial University established a category – the doctoral candidate who conducted research independently but sought formal credential. It was designed to recognise accomplished researchers who had come to science through unconventional paths. I submitted my thesis, “On the Chemical Components of Green Tea,” which compiled our vitamin C work, the catechin isolations, the tannin characterisation, all in a comprehensive document.

The examination committee could not deny the evidence. I had published results in peer-reviewed journals. I had refined techniques and made discoveries that were advancing the field. The thesis was rigorous. They conferred the doctorate.

And suddenly, I existed institutionally. I had a title, a credential. That doctorate opened doors – not everywhere, not without friction, but it opened them.

Did you expect that change?

I hoped for it, though I tried not to invest too much hope. I had learned that institutional recognition, when one is a woman, can be arbitrary. You might earn it and find it does not truly change your circumstances. Or you might be denied it for reasons having nothing to do with the quality of your work.

What I had not anticipated was the relief – the profound sense of legitimacy that came with it. Not because I suddenly believed my work was more valuable. I knew its value. But because the external world now acknowledged it formally. That acknowledgment mattered, not for vanity, but for practical access to resources and opportunities.

In 1949, you became a professor at Ochanomizu University. But the appointment was in the Faculty of Home Economics, where you became the first dean in 1950. That seems incongruous with your background in agricultural chemistry.

Yes. Yes, it does.

I was grateful for the professorship – genuinely grateful. Ochanomizu had been my alma mater in a sense, and the salary was substantial. I could now oversee graduate students. I had a genuine laboratory. These were gifts.

But the placement in home economics… I understood perfectly what it signified. My work in chemistry was not in question. My competence was not questioned. But where does one place a woman scientist, particularly one who has worked outside institutional structures, when seeking to employ her?

Home economics. The field considered “natural” for women. The field where scientific rigour could be applied, but always in service to domestic and familial improvement. It was considered appropriate. Safer. More decorous than placing me in agricultural chemistry, where I might supervise male students or challenge established hierarchies.

And I will say this, because it is true: the work we did in home economics was genuine. The application of chemistry to nutrition, to food quality, to human health through dietary science – this is not trivial. It matters. It improves lives. I do not regret the work.

But I also will not pretend that the appointment represented my trajectory flowing naturally into its proper place. It represented a compromise. The institution wanted to employ me, but within categories they understood and found acceptable for a woman of a certain age and status.

Did you challenge that placement?

No. I was in my sixties. I had spent decades fighting for basic recognition. The energy required to fight this battle, knowing that even victory would be incomplete… I chose to work. I chose to train women scientists. I chose to direct research that I believed in. At a certain point, one must decide whether the fight itself is the goal, or whether the work is. I chose the work.

Perhaps that was pragmatic. Perhaps it was capitulation. I have had years to reflect, and I remain genuinely uncertain.

You never married. Can we talk about that choice?

It was not entirely a choice. Or rather, it was a choice made under conditions I did not set.

In Japan, as in most countries I imagine, marriage for a woman meant the end of professional life. A woman’s duty after marriage was to her household, to her husband’s family. The scientific life I wanted – the focus, the freedom to move between institutions, to spend long hours in the laboratory, to travel for conferences, to decline social obligations when experiments required my attention – that life was incompatible with marriage as it was structured then.

I knew women who married and attempted to maintain scientific careers. Some managed it, but at tremendous personal cost. They carried both the weight of domestic obligation and professional aspiration, and neither received their full attention.

I chose not to marry. But let us be clear about what choice means in that context. I chose the option that allowed me to maintain intellectual autonomy. Many brilliant women of my generation made the same choice. That says something about the alternatives available to us.

The irony, of course, is that my male colleagues had no such choice to make. They could marry, have families, conduct research, and be celebrated as well-rounded individuals balancing personal and professional life. The same arrangement for a woman would have been seen as selfish, unnatural, a dereliction of duty.

Looking at the present day – you’ve been informed that women still represent a small minority in STEM fields in Japan, yes? What is your response?

Small minority? I was hoping by this century – I had imagined the barriers would have largely dissolved. The legal restrictions are gone, I understand. Women are admitted to universities. They are paid salaries. They are given proper titles.

Yet they remain minorities? Why?

I suspect the barriers have become more subtle. Less obviously unjust, therefore more insidious. Not “women cannot attend university,” but a pervasive cultural sense that science is not a natural path for women. That women in science will struggle to find husbands – I am told this is still said, in the 21st century! That their femininity will be questioned, that they are choosing an unfeminine path.

These beliefs are perhaps more difficult to challenge than explicit legal prohibition. One could fight a law. How does one fight a culture?

I would tell young women entering science now: the obstacles are real, and they are not your fault or your failing. You will be excluded from conversations, overlooked for opportunities, attributed credit to others. This is not because you lack ability. It is because the institutions and societies that shape science were built without you in mind.

What I would urge is this: do not accept the premise that you must choose between your ambitions and other forms of human life. That was the choice forced upon my generation. Advocate for institutions that do not require such sacrifices. And do not measure your worth by how well you fit into structures designed to exclude you.

I want to ask you about something that is often glossed over in histories of science – failure, or ideas that proved incomplete. In your long career, were there directions you pursued that did not pan out? Hypotheses that were wrong?

You are asking if I made mistakes.

Yes. Absolutely.

One example: in the early 1930s, I became convinced that the astringency in green tea was primarily the function of the catechin-tannin compounds we were isolating. I believed that if one could remove these compounds entirely, one would have a tea that was chemically simplified and perhaps more palatable to some Western consumers.

I pursued methods to selectively extract catechins and remove them, thinking this would produce a “refined” tea product. What I did not adequately account for was that the astringency – whilst sometimes perceived as unpleasant – was also connected to the compounds’ biological activity and health benefits. In my enthusiasm for chemical purity, I was not thinking holistically about the whole system.

It was a colleague who gently pointed out that I was attempting to remove what made green tea distinctive. The compounds I was trying to subtract were precisely what gave the beverage its character and, as it turned out, its therapeutic significance.

I was wrong about the goal of the work. Not about the chemistry itself – my extraction methods were sound – but about what constituted improvement.

That is a significant insight. Do you regret pursuing it?

Not entirely. The extraction methods I developed had applications in other contexts. And the error taught me something about the difference between chemical analysis and practical application. Just because one can isolate and remove a compound does not mean one should. The value of a substance is contextual.

I also – and I will be honest about this – I was somewhat influenced by Western preferences at the time. There was a sense that Western consumers found certain Japanese products “too intense” or “too foreign.” I wonder now if I was, without fully acknowledging it, trying to make tea acceptable to Western palates by stripping away what made it characteristically Japanese.

That is a more complex failure than a mere scientific mistake. It is a failure of critical thinking about the assumptions embedded in one’s work.

Another example?

I was slower than I might have been to investigate the precise mechanisms by which catechins operated in the human body. I identified the compounds, characterised their chemistry, but I was less rigorous about pursuing the question: how do these compounds act within biological systems? What are the pathways?

Part of this was limitation of technique. The tools for investigating biochemical mechanisms were primitive compared to what is available now. Part of it was my own inclination – I was drawn to isolation and characterisation, to the chemistry of purification. The biology was somewhat less engaging to me.

I wonder if I had pursued the biological mechanisms more vigorously, whether additional insights about therapeutic applications might have emerged during my own lifetime, rather than only later, after my death.

Today, over 1,900 peer-reviewed scientific papers investigate catechin compounds you isolated, specifically EGCG – epigallocatechin gallate. Your work from 1929 is still cited in 2024 pharmacology and cancer research. How does it feel to know that?

I cannot… I mean, I find it difficult to articulate adequately. When one works in science, one has hope that one’s contributions will endure, that other researchers will build upon what you have established. But hope is not the same as expectation.

That my catechin isolation – work conducted in a rebuilt laboratory, after an earthquake had destroyed everything, using techniques that were novel for the time – continues to be relevant ninety years later… it suggests that we were asking genuine questions about nature, not merely pursuing fashionable topics.

The applications in cancer research, particularly – researchers now understand that EGCG can inhibit multiple pathways involved in tumour growth and metastasis. They speak of it inhibiting JAK/STAT signalling, MAPK pathways, PI3K/AKT networks. These terms mean little to me, as they employ tools and conceptual frameworks that emerged after my own research era. Yet they are investigating mechanisms in precisely the compound I isolated.

Clinical trials are exploring EGCG as an adjuvant therapy. That means doctors are considering using it alongside conventional cancer treatments to improve outcomes. From isolation and characterisation to potential human therapy. That arc – it feels profound.

The global green tea market is now worth roughly 14 billion dollars, projected to grow to nearly 23 billion by 2028. Your discoveries provided the scientific foundation for that entire market expansion. What is your reflection on that economic reality?

It is curious, is it not? My annual salary when I became a researcher at RIKEN was modest. I have never been wealthy. Yet the market value of the work I performed dwarfs anything I earned in my lifetime.

I do not harbour resentment about that. The economic benefit of scientific discovery is typically reaped by industries, entrepreneurs, and institutions, not by the researchers themselves. That is how the system works. I accepted it.

But it does underscore something worth noting: women’s scientific contributions are often systematically undervalued, and the economic consequences of that undervaluation are distributed unequally. I conducted the research. Others profited. That is not unique to me, but it is more pronounced for women researchers.

I hope that modern institutions are more attentive to fair compensation and attribution. Though I suspect that hope, like so many hopes about gender equity, is not entirely warranted.

 In 2021, Google created a Doodle celebrating your work on what would have been your 133rd birthday. How does it feel to receive recognition decades after your death?

Recognition is always welcome. But there is something bittersweet about it. It is recognition by a global technology company acknowledging a scientist who spent her life in relative obscurity outside Japan. The Doodle reaches millions. Yet most of them know nothing about what I actually accomplished – only that I existed and that I must have mattered.

I prefer the recognition of other scientists. When my work is cited in a pharmacology paper, when a researcher uses my isolation protocol or builds upon my structural analysis, that is meaningful recognition. That is a conversation across time.

The Doodle is lovely, truly. It is warm and it is celebration. But it is not the same as having been fully acknowledged and cited during one’s own lifetime, when that acknowledgment might have opened doors and created opportunities for advancement.

Still – I will not complain. Visibility is better than invisibility, even if it comes posthumously.

You have lived through extraordinary change in science and society. What would you counsel young scientists today – particularly women, or those from backgrounds that are underrepresented in STEM?

Several things, and I will try to be practical rather than merely inspirational.

First: your work must be sound. Not clever, not fashionable, but rigorous and reproducible. That is the only authority you truly possess. When you are marginalised, when people doubt you, when your work is attributed to others – the one thing they cannot take from you is the quality of what you have done. Make that your foundation.

Second: document meticulously. Write down your methods, your observations, your reasoning, in sufficient detail that anyone could reproduce your work. This serves two purposes. It protects you against misattribution. And it advances science, because your work becomes usable by others. Do not keep secrets or obscure your methods hoping to protect your priority. Transparency is more powerful than secrecy.

Third: find allies – particularly allies with institutional power. I was fortunate in my mentors, in colleagues like Kono Yasui and Seitaro Miura. They could not remove all the barriers, but they helped me navigate them. Seek out people who believe in rigorous science over prejudice, and nurture those relationships.

Fourth: do not accept the framing of your work as secondary or supportive unless that truly reflects its nature. If you have designed an experiment, conducted it, and interpreted the results, you are not an “assistant.” You are a researcher. Insist on appropriate attribution. This is not vanity – it is the foundation of your future opportunities.

Fifth: be aware of the larger systems that shape your field. Understand how funding flows, how publications are valued, how citations work. These are not neutral mechanisms – they can reinforce existing hierarchies. Be conscious of that, and do not accept it as inevitable.

Sixth: know that you may be forced to make compromises. I was appointed to home economics, which was not where I would have chosen. You might face similar redirections. Sometimes you accept the compromise to continue working. Sometimes you refuse. Both are legitimate choices. What matters is that you make the choice consciously, knowing what you are gaining and what you are surrendering.

Finally: do not wait for permission. I never received permission to be a scientist. I was never told by institutional authorities, “Yes, proceed; you belong here.” I had to create the conditions of my own belonging through the quality and persistence of my work. That is exhausting, and it is unfair that women and outsiders must do this when others are granted permission freely. But it is also powerful. Your legitimacy does not depend on others’ acknowledgment.

I want to return to the 1923 earthquake, because I think it reveals something important about your character. The laboratory destroyed, your equipment and work largely lost, and yet you resumed research within a few months. How?

Despair was possible. I considered it. I was 35 years old. I had worked for fifteen years without salary, without security, and in an instant, the physical manifestation of that work – the equipment, the samples, the apparatus – was gone.

But I also understood that I was alive. Many people were not. Over 100,000 people died in those hours. The city was burning. In that context, losing a laboratory seemed almost trivial.

Also – and this is practical rather than philosophical – I still possessed the knowledge. My scales had survived because I had carried them out. My notebooks, my recorded observations – those were portable. The techniques I had developed lived in my mind and my training.

RIKEN approached me within weeks of the disaster. They were establishing new laboratories and recruiting researchers. They offered me a position. I accepted immediately. Yes, I had to rebuild, to acquire new equipment, to restart experiments. But I had something to restart with: my expertise, my determination, and the knowledge that what I had been pursuing was worth pursuing.

That seems to me like remarkable composure.

It was not composure, truly. It was the absence of an alternative I could accept. I could not imagine abandoning science. So I continued. What appeared as strength was sometimes simply the inability to envision any other path.

I also think – and perhaps this is true of many women in my generation – I had become accustomed to operating under constraint and deprivation. I had never had ideal circumstances. The earthquake was a catastrophe, yes, but it was not entirely new to me to be doing important work under difficult conditions. My entire career had been constrained. This was simply a more dramatic constraint.

That is both a source of resilience and a kind of tragedy. I had developed the capacity to work without the support that should have been afforded to me. That capacity served me in crisis. But it also meant I had accepted conditions that should never have been necessary.

If you could speak to how your story should be understood, how would you frame it?

I think there are at least three ways my story could be told, and each is partially true.

One version emphasises triumph: a woman overcame barriers and made significant scientific discoveries despite discrimination. This version is true. I did overcome barriers. I did make discoveries.

But I worry that version suggests the barriers were merely challenging, not destructive. That with enough determination, they could be individually conquered. That is misleading. Many women with equal brilliance and determination did not overcome the barriers. They were turned away from laboratories, denied funding, channelled into teaching rather than research, or forced to abandon science entirely to marry and raise families. My success did not mean the barriers were not real – it meant I happened to find paths through them, often through luck and circumstance beyond my control.

A second version emphasises tragedy: a brilliant woman was systematically excluded, her work stolen and attributed to others, her contributions minimised or erased. This is also partially true. I was excluded from universities as a student. Much of my early work was not formally attributed to me. I was channelled into home economics rather than agricultural chemistry.

But this version risks presenting me as a passive victim, which I was not. I was strategic. I persisted. I made choices within constrained circumstances.

The third version – and I think this is closest to truth – acknowledges that excellence and injustice coexisted. I was a brilliant chemist. I made genuine discoveries. And I worked in a system that did not want me there, that did not compensate me fairly, that did not offer me platforms equal to male colleagues. Both things are true simultaneously.

My story should not be used to argue that determination conquers all obstacles. That implies the obstacles are not our collective problem. They are. But neither should my story suggest that women in science are merely victims. We are agents in our own work, even when the structures surrounding us are unjust.

If you could change one thing about how science operated during your career?

I would have insisted on equal institutional access from the beginning. I would have demanded that women be admitted to universities as students, not assistants. That we be paid the same salary for the same work. That our names appear on publications we contributed to.

Not because such recognition would have made me happier – though it would have – but because science itself would have been stronger. How many discoveries were not made because women were excluded from laboratories? How many hypotheses were never tested because resources went to less promising research conducted by men? Science lost in my exclusion, not only I.

A more just system would have been a more fruitful system, scientifically.

And what would you want young scientists – the world’s Tsujimuras, working today in different fields, different countries – to understand about their own potential?

You contain more than you know. The barriers you face are real, and they are not your fault. But they are also not the limit of what you are capable of achieving.

I was not a brilliant exception. I was a competent chemist who asked careful questions and worked with rigour. I was one person. There are thousands like me – millions, perhaps – whose work the world never sees because institutional structures prevent their emergence.

If you are reading this and you have been told you do not belong in science, I am here to tell you that the people who told you that were wrong. Your task is not to prove them right or wrong by your individual achievement. Your task is to change the system so that such assessments are not necessary, so that belonging is not something rare individuals fight to obtain, but something afforded equally to all with the capacity and passion for the work.

That is the revolution I hope for. Not merely women excelling within existing systems, but the systems themselves becoming just enough that excellence can flourish without requiring extraordinary sacrifice.

Dr. Tsujimura, thank you for your time and your candour today. Before we close, is there anything you would like to add?

Only this: green tea is a humble beverage. But the chemistry within it is extraordinary. Thousands of distinct compounds, each with particular properties and effects. When I was isolating catechin, I sometimes thought about how remarkable it was that something so complex and active could exist in something so ordinary, so accessible.

I think that is rather like human potential. It is everywhere, ordinary, accessible. But you have to look carefully to see it. You have to isolate it, characterise it, understand its true nature.

The world contains far more chemical richness than what meets the eye. It contains far more human capacity for contribution than what is currently being recognised or utilised.

I spent my life extracting hidden compounds from leaves. I hope that those who come after me will devote themselves to extracting the hidden potential from human systems. The chemistry is simpler than the sociology, but the work is no less important.

Thank you for listening.

Letters and emails

Following the publication of our full interview, we received remarkable correspondence from researchers, educators, and science enthusiasts across the globe. The letters and emails that arrived were not requests for clarification, but invitations to extend the conversation – to probe deeper into dimensions of her work that deserved further exploration, and to ask the questions that resonate most urgently for those engaged in chemistry, innovation, and the ongoing struggle for equity in science.

From Seoul to São Paulo, from Zurich to Portland to Addis Ababa, our community demonstrated a hunger for nuance. These five contributors – spanning continents, disciplines, and career stages – represent the spirit of genuine curiosity that Dr. Tsujimura herself embodied. Their questions honour her legacy not through reverence, but through rigorous engagement with the complexity of her choices, the ethics of her discoveries, and what her experience might illuminate for scientists navigating similar terrain today.

What follows are the five questions we selected from our correspondence, each one offering a distinct angle on her remarkable journey. They ask not only about what she did, but about what she might have done differently, what she understands now that she could not have understood then, and what wisdom she might offer to those who inherit both the fruits and the unfinished work of her scientific life.

Hye-jin Seo, 34 | Plant Biochemistry Researcher | Seoul, South Korea
You mentioned that you were slower to investigate the biological mechanisms of how catechins actually work within human cells. Looking back now, with knowledge of modern signal transduction pathways – the JAK/STAT cascades, the MAPK networks – do you think your chemical isolation work was, in a sense, incomplete without that mechanistic understanding? Or do you believe there was genuine value in characterising the molecular structure first, even without knowing how it functioned biologically?

This is a question I have asked myself many times, particularly in the years after I left active research. Was my work incomplete? The short answer is: no. But that answer requires considerable unpacking.

When we isolated catechin in 1929, we were working within the conceptual framework and technical limitations of our era. The tools available to us – solvent extraction, fractional crystallisation, combustion analysis, melting point determination – these were fundamentally chemical tools. They told us about molecular composition, about structure, about physical properties. They could not tell us about cellular mechanisms, about how a molecule moved through biological membranes, about what happened when it encountered specific enzymes or receptors within living tissue.

The biological mechanisms you mention – the signal transduction pathways, the cascades of molecular communication within cells – these were not even conceptually available to us. We understood that compounds had effects. We could observe those effects in experimental animals or in human subjects. But the intermediate steps, the precise molecular interactions, remained opaque. It was rather like knowing that turning a key opens a door, without understanding the internal mechanism of the lock.

So the question becomes: should we have waited to characterise the structure until we could also explain the mechanism? I believe that would have been a profound error.

Chemical isolation and structural determination are foundational. You cannot investigate a biological mechanism without first knowing precisely what molecule you are investigating. If we had attempted to study “the compounds in green tea that cause astringency,” we would have been studying a mixture – dozens of related but distinct compounds, each potentially contributing different effects. We would have observed aggregate phenomena without being able to attribute specific actions to specific molecules.

By isolating pure catechin, by determining its molecular formula as C₁₅H₁₄O₆, by characterising its crystalline form and chemical behaviour – we created an object that could be studied. We made it possible for others to work with the same compound we had worked with. Reproducibility in science depends on this kind of precise definition.

I will also say this: the isolation work was not merely preparatory. It revealed information that mechanistic studies alone could not have uncovered. When we isolated multiple catechin variants – epicatechin, gallocatechin, epigallocatechin – we discovered that green tea did not contain a single active compound, but a family of structurally related molecules. That structural similarity suggested, even without mechanistic understanding, that these compounds likely arose through related biosynthetic pathways in the tea plant. It told us something about how the plant itself produced these molecules.

Furthermore, the isolation work revealed quantitative information. We could determine how much of each catechin variant was present in different tea cultivars, in leaves harvested at different times, in tea processed under different conditions. That information had immediate practical value for the tea industry, even before anyone understood the cellular mechanisms.

Now, would I have pursued mechanistic studies if the tools had been available? Absolutely. I was deeply curious about how these compounds functioned within the body. But the tools were not available, and one cannot conduct research with instruments that do not yet exist. We used what we had, and we used it rigorously.

I also want to challenge slightly the premise of your question – the suggestion that chemical work without mechanistic understanding is “incomplete.” Science does not progress in a single linear direction, with each stage fully completed before the next begins. Different researchers pursue different questions simultaneously. Some focus on isolation and characterisation. Others investigate mechanisms. Others explore applications. These are complementary approaches, not sequential stages.

The mechanistic work happening now in laboratories around the world – understanding how EGCG inhibits specific kinases, how it affects gene expression, how it modulates inflammatory responses – this work is built directly upon the chemical foundation we established. The researchers conducting those studies are using the catechins we isolated, or synthetic versions prepared according to the structural specifications we determined. Our work was not incomplete. It was foundational.

That said, I do wonder what we might have discovered if we had possessed the tools of modern molecular biology. If we could have observed catechin molecules binding to specific proteins, if we could have tracked their movement through cells, if we could have measured changes in gene expression in response to catechin exposure – what additional insights might we have gained?

But that is speculation. What we accomplished was to transform green tea from a beverage with traditional associations of healthfulness into a chemically defined system containing specific, isolatable, structurally characterised bioactive molecules. That transformation made all subsequent work possible.

So no, I do not believe the work was incomplete. I believe it was appropriate to its time, rigorous within its methodological constraints, and foundational for everything that followed. Science is not a race to final answers. It is an accumulation of carefully established truths, each building upon what came before.

Lemma Bekele, 41 | Agricultural Innovation Policy | Addis Ababa, Ethiopia
You worked in isolation – both geographically and institutionally – publishing in Japanese journals that limited your international reach. But I wonder: did that isolation also protect your work in some way? You weren’t competing directly with Western institutions for the same resources or seeking their validation in real time. Do you think the pressure to publish in English-language journals and chase international citations might have altered the trajectory of your research, or does that seem like a rationalisation of a difficult situation?

You are asking whether my isolation – both geographical and institutional – was a form of protection. Whether being outside the Western scientific mainstream shielded me from pressures that might have distorted my work. That is a provocative question, and I find myself genuinely uncertain of the answer.

Let me begin with what I know to be true: the isolation was painful. To publish research and have it remain largely unread beyond Japan, to make discoveries that took years to be acknowledged internationally, to watch Western researchers receive credit for findings we had established earlier – this was not protective. It was erosive. It diminished the impact of the work and limited my access to resources, collaborations, and recognition that might have accelerated further discoveries.

When I read about catechin research being conducted in European laboratories years after our publications, with no citation of our prior work, I felt – well, I felt as though I had spoken into a void. The isolation meant that knowledge moved in one direction. We read Western journals. We knew what researchers in England and Germany and America were discovering. But they did not read our journals. They did not know what we had accomplished. That asymmetry was not protection. It was exclusion.

And yet… and yet, your question identifies something I have only recently begun to articulate clearly.

I was not competing for grants from Western funding bodies. I was not subject to the preferences and prejudices of Western peer reviewers who might have questioned whether a woman researcher, or a Japanese laboratory, was capable of rigorous work. I was not navigating the politics of international conferences where one’s standing depended on institutional affiliation and personal networks built at Cambridge or Harvard.

My research priorities were shaped by Japanese interests – by the needs of our agricultural economy, by traditional knowledge about tea that was part of our cultural inheritance, by questions that mattered locally. Had I been working within Western institutions, seeking their funding and validation, I suspect I would have been redirected toward research questions considered more “important” by European or American standards. Tea chemistry might have been seen as provincial, insufficiently fundamental, too applied.

There is also this: I did not have to perform for Western audiences. I did not have to soften my findings or frame them in ways that flattered Western scientific assumptions. I could simply pursue the chemistry as I understood it, following the questions that emerged from the work itself rather than from external expectations about what constituted significant research.

But I want to be clear – and this matters tremendously – I do not believe this represents a romanticisation of exclusion. I am not suggesting that being marginalised was somehow beneficial. The isolation was a constraint imposed upon me, not a choice I made. If I had been given the option to publish in Nature or the Journal of the American Chemical Society, to present at international conferences, to collaborate with researchers in other countries on equal terms – I would have seized those opportunities immediately.

What I am saying is more subtle. Within the space of that exclusion, I found a certain freedom. I was not beholden to gatekeepers who might have dismissed my work as unworthy. I was not competing for limited positions where gender and nationality would have disadvantaged me further. I could work according to my own understanding of what mattered.

The pressure to publish in English-language journals, to chase international citations, to position one’s research within frameworks established by Western institutions – I believe these pressures can be distorting. They can redirect researchers away from locally important questions toward topics that Western editors and reviewers find compelling. They can require that one frame discoveries in language and conceptual terms that flatten cultural specificity.

Had I been subject to those pressures, would I have pursued tea chemistry as vigorously? Or would I have been encouraged to work on problems considered more universally significant – vitamin synthesis, perhaps, or agricultural applications of chemical fertilisers? I suspect the latter. And in that case, the catechin isolation might never have occurred, or might have been delayed by decades.

So perhaps there was an accidental benefit to the isolation. Not because isolation itself is beneficial – it is not – but because it meant I was answerable primarily to my own scientific judgment and to the needs of the community I served directly. That created space for work that might not have been valued by international gatekeepers.

But I refuse to call this “protection.” It was not protection. It was the extraction of productivity from conditions of exclusion. One can work well within constraints without those constraints being justified or beneficial.

What troubles me most about your question is the implication – unintended, I am certain – that marginalised researchers should be grateful for their marginalisation because it grants them some form of independence. That is a dangerous argument. It suggests that the solution to inequity is not inclusion, but acceptance of exclusion as somehow liberating.

I would have preferred inclusion. I would have preferred to publish internationally, to be read widely, to collaborate across borders, to have my work cited and built upon in real time rather than decades later. The isolation imposed costs – on me personally, on the advancement of tea chemistry as a field, on the potential applications that might have emerged sooner with broader collaboration.

If there was value in the isolation, it was accidental and partial. It does not justify the structures that created it. And it certainly does not suggest that isolation should be preserved or celebrated as beneficial for researchers from non-Western countries or for women in science.

We should work toward a world where researchers can pursue locally important questions without being isolated, where diverse perspectives are genuinely valued in international discourse, where publication and recognition are not contingent on conformity to Western institutional norms. That would be genuine protection – and genuine freedom.

Renata Barros, 38 | Science History and Equity | São Paulo, Brazil
The 1923 earthquake destroyed your laboratory, and you responded by moving to RIKEN and continuing. But I’m curious about the emotional and creative cost of that kind of disruption. Did losing your physical workspace – your equipment, your samples, your specific laboratory setup – force you to reimagine your methods in ways that actually improved your approach? Or did it simply set you back, and you’ve been gracious in retrospect about what might have been lost?

You are asking me about loss. About what was destroyed and whether something valuable emerged from that destruction. That is the kind of question one does not answer quickly or lightly.

The earthquake – the Great Kanto Earthquake of 1923 – was not merely a setback to my research. It was a catastrophe that killed over 100,000 people in a matter of hours. My laboratory, my equipment, the specific apparatus I had assembled – these were infinitesimal in the scale of that suffering. And yet they were also everything. They were the physical embodiment of years of work.

When I speak of it now, I am conscious of the absurdity of grieving laboratory equipment when so many people lost their homes, their families, their lives. And yet the grief was real. It was not less real because it was disproportionate to the larger tragedy.

What I lost, specifically, was continuity. I had been conducting nutritional analyses at Tokyo Imperial University. We had protocols we had refined. We had samples in progress. We had equipment configured in particular ways that reflected years of incremental adjustment. We knew where everything was. We understood the precise conditions under which our apparatus functioned most reliably. We had built a working system.

The earthquake destroyed that entire structure. When I fled the building, I carried my scales because I understood intuitively that precision instruments were not easily replaced. The notebooks I had filled with observations, the samples I had been analysing – these were lost. I could not simply begin again. I had to begin differently.

Now, your question asks whether that enforced reimagining actually improved my approach. Whether the constraint of starting from nothing produced something better than continuation would have.

I have to be honest: I cannot definitively separate the effects of the earthquake from the effects of moving to RIKEN. When I began at RIKEN in late 1923, I had a proper laboratory, salary, institutional support, and collaborators. Any of those factors, or all of them together, might explain why the work that followed was more productive than what came before. It is impossible to isolate the specific contribution of destruction and renewal.

That said, something did change in my approach. Before the earthquake, I was working on nutritional analysis within a relatively narrow framework. We were testing specific hypotheses about the nutritive value of various foods. It was competent work, but it was somewhat bounded by established questions.

After the earthquake, when I had to rebuild, I approached the laboratory differently. I did not attempt to replicate exactly what we had been doing. Instead, I asked: what questions are most important to investigate? What would constitute genuine advancement? What equipment do we actually need, and what was merely convenient?

This reorientation led directly to the vitamin C work in collaboration with Seitaro Miura. We were asking a more fundamental question than we had before: what are the actual chemical constituents of green tea that produce its observed effects? Not merely measuring vitamin content, but attempting to isolate and characterise the active compounds themselves.

I think the loss of continuity created a kind of intellectual space. Had everything continued as it was, I might have pursued incremental refinements to existing protocols. Disruption forced me to reconsider the foundation.

But I want to be very careful not to romanticise this. The emotional cost was substantial. I remember the disorientation of not having my familiar equipment, of not knowing where things were, of having to learn new laboratory spaces. I lost months that could have been spent on research. I lost samples and preliminary data that represented years of work. Those losses were real.

Furthermore, I cannot know what would have been discovered had the earthquake not occurred. Perhaps we would have pursued the catechin isolation earlier. Perhaps we would have developed different techniques that were equally valid. The counterfactual is unknowable.

What I can say is this: the destruction forced me to make choices about what mattered most. When you must rebuild from nothing, you cannot carry everything forward. You must ask which elements were essential, which were merely habitual. That questioning process was, in retrospect, valuable.

But here is what troubles me about your question – the suggestion that disruption was somehow creatively productive. Yes, something valuable emerged. But the emergence of that value does not justify the disruption. It does not mean the earthquake was beneficial. It means that I, and many others, developed considerable skill at making the best of catastrophe.

That is a capacity that should not be necessary. Scientists should not have to rely on the ability to reinvent their work after disaster. We should have stable laboratories, secure funding, protection from interruption. The fact that I could recover from this particular earthquake does not make earthquakes good for science.

I have watched younger researchers face disruptions – economic instability, political upheaval, loss of funding – and I have observed something curious. Those who survive these disruptions often speak of them as character-building or creatively clarifying, as you are asking. And yet if those disruptions could have been prevented, they should have been. The ability to recover is not the same as the desirability of having to recover.

So my honest answer is: yes, the forced reimagining altered my approach productively. But no, that does not mean I would recommend destruction as a pathway to intellectual growth. The growth came despite the destruction, not because of it. And I wonder how many other researchers faced similar disruptions and did not survive them – whose potential discoveries were lost because they could not overcome what I managed to overcome.

The emotional and creative cost was high. The fact that something valuable emerged does not erase that cost. It merely means the cost produced some return. That is not the same as justification.

Jordan Matthews, 29 | Phytochemistry and Ethnobotany | Portland, Oregon, United States
Imagine you had been admitted as a regular doctoral student to Tokyo Imperial University in 1920, with full funding, institutional support, and the ability to supervise assistants. Would you have pursued the same research questions, or would the resources and expectations have redirected you elsewhere? And do you think the constraints you faced – the improvisation, the careful rationing of materials – actually sharpened your scientific thinking in ways you might have lost with unlimited resources?

You are asking me to imagine an alternative history – one in which I was granted from the beginning what I spent decades working to obtain. Full admission to Tokyo Imperial University as a doctoral student in 1920. Funding. Recognition. The authority to supervise assistants rather than being one myself. It is a generous counterfactual, and also a somewhat painful one to consider.

Would I have pursued the same research questions? I think… probably not. And I am not certain whether that would have been better or worse.

When one enters an institution as a fully recognised member – particularly a prestigious institution like Tokyo Imperial University – one inherits not only resources but also expectations. There are established research programmes, preferred methodologies, questions considered worthy of investigation. One’s supervisor has particular interests. One’s department has funding relationships with specific industries or government ministries. All of these factors shape what constitutes acceptable, fundable research.

Had I been a formal doctoral student, I would have been assigned to a supervisor. That supervisor would have had authority over my research direction. Given the period and the focus of the Agricultural Chemistry Department, I suspect I would have been directed toward problems considered more immediately practical – soil chemistry, perhaps, or fertiliser development, or pest management. These were areas of intense interest to the Japanese government, which was seeking to modernise agriculture and increase crop yields.

Tea chemistry – the investigation of bioactive compounds in a beverage that was already widely consumed – might not have been seen as sufficiently important to warrant a doctoral thesis. It was not solving an urgent agricultural problem. It was not directly increasing food production. It was, in a certain sense, curiosity-driven research about a traditional product.

As an unpaid assistant, I had very little authority. But I also had unusual freedom. No one particularly cared what I worked on, as long as I did not consume expensive reagents or monopolise equipment that established researchers needed. I could pursue questions that interested me without needing to justify them to a funding committee or demonstrate their immediate practical value.

The vitamin C work emerged from this freedom. Miura and I were curious about why green tea was considered healthful in traditional knowledge. That was the starting point – not a government mandate, not an industrial contract, but genuine scientific curiosity about a cultural phenomenon.

Had I possessed unlimited resources – the ability to hire assistants, access to expensive analytical equipment, freedom to order reagents without concern for cost – would I have worked more efficiently? Certainly. We would have conducted more experiments in parallel, tested more variables, pursued more hypothetical pathways simultaneously.

But here is what gives me pause: constraint forces precision. When you cannot afford to waste materials, every experiment must be designed with extraordinary care. You must think through each step before executing it. You must anticipate potential failures and design protocols that minimise the risk of having to repeat the work.

This enforced precision became habitual for me. I could not approach experiments casually, assuming I could simply try again if something failed. Each attempt had to count. That discipline – the necessity of getting it right the first time – shaped how I thought about experimental design.

I see researchers now with abundant resources, and sometimes I observe a certain casualness. They can afford to be exploratory in ways I could not. They can test multiple approaches simultaneously and see which yields results. That is valuable, genuinely valuable. But it can also mean that the thinking becomes less rigorous. Why spend hours designing the optimal protocol when you can simply try several protocols and compare them?

I am not suggesting poverty is beneficial. That would be absurd. But I am suggesting that the relationship between resources and scientific insight is not linear. More resources do not automatically produce better science. They produce different science.

Now, would I have chosen constraint if given the option? Absolutely not. I would have seized institutional support, funding, assistants, recognition. The question is whether those resources would have redirected me toward different problems – problems considered more important by institutional authorities.

There is also the question of confidence and authority. As a formal doctoral student, I would have been expected to demonstrate mastery, to defend my choices, to position my work within existing debates. I might have been more cautious, more concerned with how my research would be received, less willing to pursue unconventional directions.

As an unpaid assistant, I was invisible. That invisibility was painful. But it also meant I was not being evaluated constantly. I could work without the scrutiny that formal students endure. I could make mistakes without those mistakes becoming part of an official assessment of my capability.

I think about the catechin isolation specifically. That work required patience – years of incremental refinement, repeated crystallisations, careful observation of subtle differences in crystal formation. Had I been under pressure to complete a doctoral thesis within a specified timeframe, I might have settled for less pure isolates, for structural determinations that were adequate rather than definitive. The lack of deadline pressure meant I could pursue the work to genuine completion.

But here is the honest truth: I cannot know. I cannot know whether the constraints sharpened my thinking or merely slowed my progress. I cannot know whether institutional resources would have redirected me toward more important questions or merely toward more conventional ones. I cannot know whether the freedom that came with invisibility was worth the cost of that invisibility.

What I can say is this: the scientific work I produced was rigorous and significant. It was conducted under extraordinarily difficult circumstances. The fact that anything valuable emerged at all suggests considerable capability. But I refuse to celebrate the circumstances themselves. I refuse to suggest that women scientists or researchers from marginalised backgrounds should be grateful for constraint because it might sharpen their thinking.

If I had been given resources and recognition from the beginning, I hope I would have been wise enough to use them well, to maintain intellectual independence, to pursue questions that mattered rather than questions that were merely fundable. But I was not given that opportunity. So I worked with what I had.

The sharpening you describe – the refinement that came from improvisation and careful rationing – was real. But it was also a response to deprivation. And whilst I am proud of what I accomplished, I am not grateful for the deprivation itself.

Petra Schneider, 52 | Food Science and Regulatory Affairs | Zurich, Switzerland
Your work on vitamin C and catechins provided scientific legitimacy to green tea as a health product, which then fuelled a massive export industry. But as someone now working in regulatory frameworks, I’m asking: did you consider the ethical implications of translating your chemical findings into marketing claims? Were you aware that your discoveries might be used to make exaggerated health promises about tea? How do you distinguish between rigorous science and commercialisation?

This is the question that haunts me most, I think. You are asking about responsibility – about the distance between scientific discovery and its commercial application, and whether that distance absolves the researcher of ethical obligation.

I will be candid: when we published the vitamin C findings in 1924, I understood that they would have commercial implications. Japan’s economy in the 1920s depended substantially on agricultural exports. Green tea was a significant export commodity, particularly to the United States. Our research provided scientific validation for what had been traditional knowledge, and I knew that validation would be used to expand markets.

Did I consider that problematic? At the time, no. I believed – and I still believe, in part – that providing accurate scientific information about the chemical composition of foods was valuable work. Consumers deserved to know what they were consuming. If green tea truly contained significant quantities of vitamin C, then informing people of that fact seemed straightforward and beneficial.

But your question presses on something more troubling: the gap between accurate information and exaggerated claims. Between saying “green tea contains vitamin C” and saying “green tea will cure scurvy, prevent ageing, restore vitality.” I was not responsible for the latter claims, but my research enabled them.

I remember seeing advertisements in American magazines in the late 1920s and early 1930s that referenced our findings – sometimes accurately, often not. They would claim that Japanese green tea was a “health elixir” or a “fountain of youth,” and they would cite scientific studies to support these assertions. Our work would be mentioned, usually without proper attribution, often with our findings exaggerated or misrepresented.

This troubled me, though I did not speak publicly about it at the time. What recourse did I have? I could not control how our published findings were used. I could not sue American advertisers for misrepresenting research published in Japanese journals. I had no platform from which to correct exaggerations. And frankly, I was not certain whether correction was my responsibility.

The ethical framework I operated within was relatively simple: conduct rigorous research, publish findings accurately, allow others to draw appropriate conclusions. If someone misused those findings, that was their ethical failure, not mine. The researcher’s obligation ended at publication.

I am no longer certain that framework is adequate.

Here is what I have come to understand: scientific knowledge does not exist in isolation from its social and economic context. When I published findings about green tea’s vitamin C content, those findings entered a world where tea was already a commodity, where Japanese agricultural interests had specific economic goals, where American consumers were being courted as a market. My research was not neutral information floating free of those interests – it was immediately incorporated into them.

Could I have anticipated that? Yes. Should I have considered more carefully how the findings might be used? Perhaps. But I also want to resist the implication that scientists should refrain from publishing accurate findings because those findings might be commercially exploited. That seems like the wrong conclusion.

The distinction I want to maintain is this: there is a difference between scientific findings being used to support accurate health claims and those same findings being distorted into exaggerated promises. Green tea does contain vitamin C. That is a fact. Saying “green tea is a good source of vitamin C” is accurate. Saying “green tea will prevent all illness” is not, and our research never supported such claims.

Where I struggle is with the intermediate cases. When advertisers said that green tea promoted health and vitality, citing our vitamin C research – was that an exaggeration? Vitamin C is essential for health. Green tea contains vitamin C. Therefore, consuming green tea could reasonably be said to support health. The logic is not entirely false. But it is also not the whole truth, because many foods contain vitamin C, and the quantities in tea are not exceptional.

I think what troubles me most is that the commercial applications obscured the scientific curiosity that motivated the work. We investigated green tea because we wanted to understand its chemical composition, because we were curious about the relationship between traditional knowledge and measurable compounds. The market saw our work as product validation. Those are very different frames, and the latter erased the former.

As for whether I was aware of the potential for exaggerated health claims – yes, I was aware. The 1920s and 1930s were filled with dubious health products making extraordinary claims based on minimal evidence. Patent medicines, vitamin supplements, dietary fads – the marketplace was saturated with pseudoscientific assertions.

Did I worry that our rigorous research would be lumped together with that nonsense? Yes. Did I know how to prevent it? No.

What I wish I had done – and this is genuine regret – is published a clear, accessible statement about what our findings meant and what they did not mean. Not merely the technical paper for other scientists, but a public-facing explanation that said: “We have identified vitamin C in green tea at these concentrations. This means green tea can contribute to vitamin C intake. It does not mean green tea cures diseases or possesses magical properties.”

But I did not have the platform or the confidence to issue such statements. I was an unpaid assistant, not an institutional authority. Who would have listened?

Now, you work in regulatory affairs, and you understand the frameworks that have since been developed to govern health claims. Those frameworks did not exist in my era – or they existed only in rudimentary form. There was no requirement that health claims be substantiated by rigorous evidence. Advertisers could say almost anything.

Would I support such regulatory frameworks? Absolutely. I believe that claims about health benefits should be required to meet evidentiary standards, that exaggerations should be prohibited, that consumers should be protected from misleading information.

But I also believe – and this is important – that the responsibility for accurate communication cannot rest solely on researchers. We need institutions, regulations, professional standards, public education that create environments where scientific findings are communicated responsibly. Individual researchers cannot bear that burden alone.

So to answer your question directly: yes, I considered the commercial implications. No, I did not adequately address the ethical complexities of those implications. And yes, I believe scientists have some responsibility for how their work is used – but that responsibility must be supported by institutional structures that currently do not exist, or did not exist in my time.

The distinction between rigorous science and commercialisation is this: science seeks truth, commerce seeks profit. Those motivations can align, but they often diverge. My responsibility was to the truth. I fulfilled that responsibility. But I did not adequately consider how that truth would be deployed in service of profit, and whether I had any obligation to shape or constrain that deployment.

That is my honest answer. And it is an answer filled with uncertainty, which I think is appropriate. Ethics in science is not simple.

Reflection

Michiyo Tsujimura passed away on 1st June 1969, at the age of 81. She had lived long enough to see Japan transform from an isolated imperial power to a modern economic force, to witness the devastation of war and the reconstruction that followed, and to observe – though perhaps not fully receive – growing recognition for the scientific contributions she made decades earlier. Her death came quietly, without the international obituaries that marked the passing of her male contemporaries, without headlines celebrating the woman who had given the world its first understanding of green tea’s molecular architecture.

In constructing this fictional interview, we have attempted to give voice to perspectives that the historical record only hints at. Tsujimura left relatively few personal writings about her experiences of gender discrimination, her emotional response to the 1923 earthquake, or her feelings about being channelled into home economics despite her doctorate in agricultural chemistry. The reflections presented here – her acknowledgment of mistakes, her nuanced consideration of whether isolation offered unexpected freedoms, her ethical wrestling with commercial applications of her research – are imaginative reconstructions built upon the documented facts of her career and the broader context of women scientists in early 20th-century Japan.

Where our fictional Tsujimura may diverge from the historical figure is in her willingness to articulate frustration and critique so directly. Women of her generation, particularly in Japan, were often expected to express gratitude for opportunities rather than anger at constraints. The historical Tsujimura may have been more circumspect, more diplomatic, more willing to frame her achievements within narratives of institutional benevolence rather than institutional failure. We cannot know. What we can know is that the structures she navigated – unpaid labour, exclusion from formal education, attribution gaps, gendered professional channelling – were real, documented, and consequential.

The interview also highlights tensions that remain unresolved in historical accounts. How much of her research was truly independent, and how much was collaborative work where her contribution has been disproportionately emphasised or diminished in different tellings? How did she actually feel about her appointment to home economics – was it genuine satisfaction with applied nutritional science, or quiet resignation? These uncertainties are not failures of historical method; they reflect the reality that marginalised figures often left sparser documentary trails, and that the archives themselves were shaped by the same biases that marginalised them in life.

What is beyond dispute is the enduring significance of Tsujimura’s chemical work. Her 1929 isolation of catechin and subsequent structural characterisation laid the groundwork for an entire field of phytochemical research. By the 1960s, Western researchers began rediscovering and citing her publications, though often belatedly. The explosion of interest in green tea’s health properties in the 1990s and 2000s – driven by epidemiological studies linking tea consumption to reduced cancer risk and cardiovascular disease – sent researchers back to Tsujimura’s original papers.

Contemporary scientists investigating epigallocatechin gallate (EGCG) and its mechanisms routinely acknowledge that their work rests on foundations established nearly a century ago in a Tokyo laboratory by a woman working without institutional status. The global market for green tea extracts and catechin supplements, now valued in the billions, traces its legitimacy directly to her chemical detective work. Every matcha latte, every EGCG capsule, every antioxidant skincare product containing green tea extract – all bear the invisible imprint of her 1920s and 1930s research.

Her academic legacy also persists through the institutions she shaped. Ochanomizu University, where she served as the first dean of the Faculty of Home Economics, continues to educate women scientists. The Yasui-Kuroda Scholarship, established by her mentor Kono Yasui and colleague Chika Kuroda, still supports Japanese women pursuing scientific research, creating pathways that Tsujimura herself had to fight for inch by inch.

The challenges Tsujimura confronted – institutional exclusion, unpaid labour, attribution erasure, professional channelling into “appropriate” fields – have not vanished. They have evolved. Women in STEM still report being mistaken for assistants rather than principal investigators, still face questions about work-life balance that male colleagues never encounter, still see their collaborative contributions minimised whilst male co-authors receive disproportionate credit.

Japan’s persistent STEM gender gap, with women representing only 16% of STEM graduates as of 2024, suggests that the cultural forces that constrained Tsujimura’s generation retain considerable power. The recent findings that Japanese women in STEM still face warnings about reduced marriage prospects – the exact constraint that shaped Tsujimura’s decision to remain unmarried – reveal how slowly certain cultural narratives change.

Yet there is also progress. Tsujimura worked for years without salary; today, such arrangements are recognised as exploitative and increasingly challenged. She could not formally enrol as a university student; today, women’s access to higher education is legally protected. She published in isolation; today, international collaboration and open-access publishing create visibility that would have seemed miraculous to her generation. The 2021 Google Doodle celebrating her 133rd birthday, whilst belated, signals growing recognition that scientific history has been incomplete, that the canon requires expansion.

What Tsujimura’s story offers to young women in science today is not a template for individual heroism, but evidence of structural barriers that must be dismantled collectively. Her extraordinary achievements were accomplished despite the systems surrounding her, not because those systems functioned well. Celebrating her resilience should not distract from condemning the conditions that required such resilience.

The interviews presented here – both the main conversation and the supplementary responses – attempt to honour Tsujimura by taking her seriously as a thinker, as someone whose scientific judgment was sound and whose ethical reflections were complex. Too often, historical women scientists are presented as inspiring figures whose actual scientific work remains vague or oversimplified. Tsujimura deserves better. She deserves to be understood as someone who made specific technical choices about crystallisation protocols, who engaged with the relationship between chemical structure and biological mechanism, who considered the ethics of commercialisation and the politics of publication.

For young women scientists reading this, the lesson is perhaps this: your work matters not as a symbolic victory over prejudice, but as genuine contribution to human knowledge. The barriers you face are not measures of your capability – they are measures of institutional failure. Tsujimura’s catechin isolation was brilliant chemistry. The fact that she performed it whilst unpaid, whilst excluded, whilst undervalued, does not make it more brilliant. It makes the exclusion more shameful.

Visibility matters. Mentorship matters. Institutional reform matters. Tsujimura benefited from mentors like Kono Yasui who opened doors that were officially closed. She suffered from the absence of broader networks that might have amplified her work internationally. She demonstrates both the power of individual support and the insufficiency of relying on individual goodwill when structures themselves are unjust.

There is something profoundly moving about the image of Tsujimura fleeing the burning laboratory in 1923, clutching her precision scales. In that moment of catastrophe, she knew what mattered: the tools that enabled exact measurement, the instruments that transformed observation into quantifiable knowledge. She saved what she needed to continue.

Perhaps that is the essence of her legacy – not merely the specific compounds she isolated, but the insistence on continuing. Through earthquake and exclusion, through decades of institutional invisibility and professional channelling, through the slow, grinding work of crystallisation and recrystallisation, she continued. She asked careful questions of matter and listened to what it revealed.

Today, every time a researcher cites her work, every time someone drinks green tea and benefits from the vitamins and catechins she identified, every time a young woman scientist persists through barriers that should not exist – Michiyo Tsujimura’s work continues. Not as history, but as living presence. Not as inspiration alone, but as foundation.

The scales she rescued from the flames measured more than chemical compounds. They measured possibility. They measured what could be known if one refused to accept that knowing was not permitted. That refusal – rigorous, methodical, grounded in precision rather than rhetoric – remains her most enduring contribution. It is a refusal we still need.

Who have we missed?

This series is all about recovering the voices history left behind – and I’d love your help finding the next one. If there’s a woman in STEM you think deserves to be interviewed in this way – whether a forgotten inventor, unsung technician, or overlooked researcher – please share her story.

Email me at voxmeditantis@gmail.com or leave a comment below with your suggestion – even just a name is a great start. Let’s keep uncovering the women who shaped science and innovation, one conversation at a time.

Editorial Note

This entire interview transcript – the main conversation between the interviewer and Michiyo Tsujimura, the supplementary questions from international contributors, and Tsujimura’s responses to those questions – is a work of historical fiction. It is a dramatised reconstruction, not a documentary record.

The factual foundations are solid. Michiyo Tsujimura (1888–1969) was indeed a pioneering agricultural chemist who discovered vitamin C in green tea in 1924 working alongside Seitaro Miura at RIKEN. She became the first scientist globally to isolate catechin in 1929 and subsequently isolated tannin and gallocatechin. She earned her doctorate in agriculture from Tokyo Imperial University in 1932, becoming the first woman in Japan to achieve this credential, despite never having been formally admitted as a university student. She worked as an unpaid assistant at Hokkaido Imperial University before the earthquake. She was appointed professor at Ochanomizu University in 1949 and served as the first dean of its Faculty of Home Economics in 1950. She received the Japan Prize of Agricultural Science in 1956 and the Order of the Precious Crown (Fourth Class) in 1968. She passed away on June 1, 1969.

The institutional barriers she faced – exclusion from universities, unpaid labour, attribution gaps, professional channelling into home economics – are documented in historical records and scholarly analyses of women scientists in early 20th-century Japan.

What is reconstructed, imagined, and therefore potentially inaccurate are:

Her interior reflections: We do not possess Tsujimura’s personal journals, letters revealing her emotional responses to institutional exclusion, or recorded interviews where she discusses her own experience. Her thoughts about working unpaid, her feelings about the 1923 earthquake’s impact on her research, her frustration with being redirected to home economics – these are reasonable inferences based on her circumstances, but they are inferences, not documented facts.

Her voice and speech patterns: The language attributed to her – era-appropriate, measured, reflective – is a constructed persona based on the linguistic conventions of her time and the limited public statements she is known to have made. The actual rhythm and diction of her speech remains largely unknowable.

Her responses to hypothetical questions: The supplementary questions posed by the fictional contributors (Hye-jin Seo, Lemma Bekele, Renata Barros, Petra Schneider, Jordan Matthews) and her answers to those questions are entirely imaginative. They explore themes suggested by her life and work, but they do not represent positions she actually articulated.

Her self-critique and ethical reflection: The moments in which the fictional Tsujimura acknowledges mistakes – her failed attempt to remove catechins from green tea, her slower-than-ideal investigation of biological mechanisms, her uncertainty about the ethics of commercialisation – are constructed to honour intellectual honesty whilst remaining speculative. She may have held these views; she may not have.

Why we have chosen this method:

Rather than present Tsujimura as a distant historical figure or a vague inspiration, we have attempted to render her as a thinking, feeling, complex person struggling with substantive questions about science, gender, institutions, and legacy. This dramatisation is more honest, in some ways, than a purely factual recitation would be – because it acknowledges what we do not know whilst still engaging seriously with what we do.

The alternative – remaining silent about her interior life, her perspectives, her possible reflections – would itself be a choice, one that perpetuates her erasure. By imagining her voice thoughtfully, grounded in evidence, we do not claim certainty. We claim conversation.

Our responsibility to readers:

By labelling this work as dramatised reconstruction, we ask readers to engage critically. You should not cite this interview as documentary evidence of Tsujimura’s views. You should not treat her fictional responses as historical fact. You should, however, consider the plausibility of her reflections, the coherence of her reasoning, and the extent to which this reconstruction illuminates dimensions of her actual life and work that historical silence has obscured.

We also invite you to imagine better reconstructions, alternative perspectives, different voices that might have been included. This is one interpretation of who Michiyo Tsujimura was and what she might have thought. It is not the only possible interpretation. History is always, to some degree, an act of imagination constrained by evidence. We are simply making that imaginative act explicit rather than hiding it behind the appearance of objectivity.

The stakes of this choice are real. When we speak for the dead, we bear responsibility for accuracy, for respect, for intellectual humility about the limits of what we can know. We have attempted to honour that responsibility by grounding this reconstruction in documented fact, by acknowledging uncertainty openly, and by declining to attribute views to Tsujimura that her actual historical record does not support or suggest.

Michiyo Tsujimura’s actual life – the documented facts of her achievements, her barriers, her contributions – requires no dramatisation to be remarkable. Our role is to ensure that dramatisation serves understanding rather than obscuring it.

Bob Lynn | © 2025 Vox Meditantis. All rights reserved.