Yasui Kono was born in 1880 in Kagawa Prefecture, where her family ran a shipping business; they were in favor of education for their daughters as well as their sons, sending her to high school in her home prefecture and then to the Women’s Higher Normal School (later Ochanomizu University) in Tokyo. She graduated in 1902, taught high school for three years, and became the first graduate student in science at the Women’s Higher Normal School, publishing zoological and botanical articles in Japanese and international scientific journals, in all cases as the first Japanese woman to do so. (Although she wrote a physics textbook for girls’ high schools while teaching herself, it was rejected by the Ministry of Education because they believed that a woman could not have written it.) She became an assistant professor at her alma mater after receiving her graduate degree there in 1907.

Although Kono’s application to study abroad was endorsed by multiple eminent scientists, it was rejected on the basis of her gender by the Japanese Ministry of Education, and finally accepted only on the grounds that she included “home economics research” in her goals and that she committed herself solely to research, without marrying. In the end, she studied cells at the University of Chicago in 1914 and coal at Harvard in 1915, returning to Japan the following year to research coal further at the University of Tokyo. In 1927 she completed her doctoral thesis on coal, discussing its botanical origins among other points; to collect research samples, she made a practice of having herself lowered into coal mines, horrifying her friends and family. This thesis made her the first woman in Japan to receive a doctoral degree in the sciences.

Alongside her research she taught at the University of Tokyo and at the Women’s Higher Normal School. She also founded a scientific journal on cytology, studied plant genetics, and after the war researched the botanical effects of the atomic bomb. For fifty years she shared a home with her much younger sister Masa, a painter who did the housekeeping so that Kono could concentrate on her work. She retired as a full professor in 1952. Along with fellow scientist Kuroda Chika, she created the Yasui-Kuroda Scholarship for women at Ochanomizu University researching science. She died in 1971, the recipient of numerous honors, with her bedside table stacked with well-thumbed scientific texts.

Sources
https://www.smithsonianmag.com/science-nature/how-pioneering-botanist-broke-down-japans-gender-barriers-180967595/ (English)
https://archive.mith.umd.edu/gcr/text/text_1358298125.html (English)
https://www.ge-at-utokyo.org/kono-yasui (English; nice photos)
[There are quite a few articles in English about Kono online, but nothing on her in any of my Japanese source books; maybe because the authors tend to be more interested in literature and the arts than in the sciences?]