When Yasui was endorsed by
Kiichi Mitake to the
Japanese Ministry of Education to study in Germany, they refused to give her permission because of their belief that “a woman cannot achieve much in science.” the professor of
University of Tokyo, she was only allowed on the condition that she listed "home economics research" alongside "scientific research" on her application and that she agreed not to marry and instead commit herself to her research. She travelled to
Harvard University in 1915, where she conducted research on coal under Professor
E. C. Jeffrey. She returned to Japan in June 1916 and continued researching coal at Tokyo Imperial University (now the
University of Tokyo) until 1927. She taught genetics there from 1918 to 1939, and was made a professor at the Women's Higher Normal School in Tokyo in 1919. She completed her doctoral thesis, "Studies on the structure of
lignite, brown coal, and bituminous coal in Japan", in 1927, becoming the first woman in Japan to complete a doctorate in science. In 1929, Yasui founded the cytology journal
Cytologia. From 1924 onwards, she researched the genetics of poppies, corn and
Tradescantia species, and in 1945 she began a survey of plants that had been affected by
nuclear fallout after the
atomic bombings of Hiroshima and Nagasaki. When
Ochanomizu University was established under its current name in 1949, Yasui was appointed professor. She retired in 1952, becoming a professor emerita. By 1957 she had published a total of 99 scientific papers. == Legacy ==