I was born in 1920 in Tokyo. The only sibling of a brother 10 years older, I was doted on almost excessively by my mother and my father, an electrical engineer. When I began elementary school, I cried every morning when I had to leave my mother's side. But I quickly came to love school, especially arithmetic and science. Each time I learned something new, I felt as if I had climbed a step higher and could see that much more of the world around me. My teacher recognized my eagerness to learn and let me use the arithmetic textbook for a higher grade level.

I also remember how our teachers stayed after school helping those of us hoping to continue in girls' higher school prepare for the admissions tests. I remember thinking that they had children of their own and must surely be eager to return home. Even then I grasped the importance of gaining one's independence. That was when I decided that women, just like men, should learn a skill or profession and go out into the world. At the time, I wanted to be a medical doctor. But although I passed the entrance exam for Tokyo Women's Medical Professional School, the interview was not encouraging, and I decided not to accept admission. In 1939, I entered the new Imperial Women's Science College (now the Faculty of Science of Toho University) as one of its first students.

At the Science College I majored in physics. Built during the war years, the college had poor facilities, and students were encouraged to work as interns in laboratories elsewhere during the summer holidays. I was interested in questions like What makes it rain? so I was sent to work with Dr. Yasuo Miyake of the Central Meteorological Observatory (now the Japan Meteorological Agency). Interns were normally called on to do menial chores, such as washing beakers, but Dr. Miyake said, "If you're going to study science, you'll need a theme for your graduation thesis," and the topic he assigned to me was "A Physicochemical Study of Polonium." Polonium is a radioactive element discovered by Marie Curie, the famed Polish-born scientist whom we women science students worshipped as our patron saint at the time. I was ecstatic, even though I had practically no knowledge whatsoever about radioactivity. I remember stopping in a bookshop on my way home to buy a book on the subject.

It was still wartime when I graduated, and many job offers came from engineering- and science-related departments of the army and navy. More than three-quarters of my friends found work in the military, but I did not feel like getting directly involved in the war effort, so I made up my mind to work in the Central Meteorological Observatory with Dr. Miyake. I believed that the goals of science and technology should be the welfare and happiness of humankind.

In 1943, I entered the Central Meteorological Observatory and began to devote myself to the scientific study of the atmosphere and the oceans, with a special emphasis on radioactive matter found in atmospheric dust and rain. In 1945, with the war raging and Tokyo in flames, the Central Meteorological Observatory's Research Division moved to Nagano Prefecture. Dr. Miyake, head of the division, lost no opportunity to council me and my fellow researchers: "The war will be over soon. You have to study hard to prepare for what's ahead," he told us. "A scientist has to be more than a technician. A scientist has to be a philosopher," he would exhort. In August that year, when atomic bombs were dropped on Hiroshima and Nagasaki, I was shocked by the realization that science and technology could be used for such atrocities.

In March 1954, the crew of the Japanese fishing vessel Lucky Dragon V was exposed to radioactive fallout from the explosion of a hydrogen bomb on Bikini Atoll, where the United States was conducting nuclear tests. The Meteorological Research Institute—as the Research Division had been renamed&$151;was called on to analyze the "ashes of death" that had sickened the men. Dr. Miyake immediately threw himself into the project, saying, "This is exactly the kind of problem we should be studying." When Dr. Miyake published research concluding that the fallout was making its way to the seas around Japan on the Kuroshio Current, American scientists refused to believe him. Later, however, the results of a joint Japan-U.S. research project in which I participated—working at the University of California Scripps Institution of Oceanography for about a year beginning in 1962—proved that the Japanese method of measuring ocean radioactivity was much more accurate than the American method.

In 1957 I received my doctorate in science from the University of Tokyo for my dissertation "The Behavior of Carbonic Matter in Natural Water," becoming the first woman to receive a doctorate in science from this prestigious university. In 1958, I was sent to attend the fourth world conference of the Women's International Democratic Federation in Vienna at the recommendation of Raicho Hiratsuka, founder of the women's rights magazine Seitou (Bluestocking). Representing Japan in the field of science, I urged the abolition of nuclear weapons from a scientist's standpoint.

I continued my work measuring artificial radioactive substances in the ocean and atmosphere and was able to show how radioactive fallout from Chinese and Soviet nuclear tests was being carried by wind and ocean currents to the Sea of Japan. At the 1961 International Symposium on Marine Sciences, I reported the results of a study in which we had measured levels of radioactivity in ocean water at the surface and progressively deeper levels, at intervals of 1,000 meters. The survey had detected radioactivity as deep as 8,000 meters below the surface, forcing scientists to rethink their ideas about how quickly water from the surface and the ocean depths mix. Until then, the prevailing opinion was that it took more than 1,000 years for all the water in the oceans to mix; new calculations based on our research indicated that it actually took only a few hundred years.

Studies of this sort began to catch the attention of the media, and after the report on radioactive rain came out, it was common for reporters to crowd into Dr. Miyake's laboratory at the Meteorological Research Institute whenever it rained to ask how much radioactivity there was in the rain that had just fallen. Dr. Miyake not only gave generously of his assistance to students and researchers regardless of gender, he also explained things patiently to reporters with no specialized knowledge of radioactivity, saying, "It wouldn't do to have it reported inaccurately."

Nuclear testing is not the only source of radioactivity. A research committee in which I participated revealed that the radioactive matter in water emitted from the reactors of nuclear submarines had been detected in large quantities on the ocean floor at Japanese ports where such submarines call. If fish and other marine products are contaminated by radioactivity, this raises a health issue for the people who eat them. Along with my research, I have been active in such organizations as the Peace Society for the Lucky Dragon V and the Geochemistry Research Association. I have tried to alert the public to the dangers of radioactive contamination from nuclear tests and from the waste from nuclear power plants and submarines.

Another theme of my career has been efforts to assist, encourage, and recognize the achievements of women scientists. In 1958, acting on a suggestion by Raicho Hiratsuka, I formed the Society of Japanese Women Scientists. In 1980, when I retired from the Meteorological Research Institute, I established the Association for the Bright Future of Women Scientists, together with the Saruhashi Prize, to encourage women involved in scientific research and honor their achievements. The prize, which has been awarded each year to women scientists under the age of 50 in a wide variety of fields, celebrated its twentieth anniversary in the year 2000. Many women scientists continue to strive toward better research and higher scientific ideals as they pursue their careers in the century ahead.

Excerpt from Blazing a Path: Japanese Women's Contributions to Modern Science, organized by The Committee for the Encouragement of Future Scientists. (See general references for full citation).