Kiyoshi Oka (April 19 1901 - March 1 1978) was a Japanese mathematician, who did fundamental work in the theory of several complex variables. He was born in Osaka. He went to Kyoto Imperial University in 1919, turning to mathematics in 1923 and graduating in 1924.
He was in Paris for three years from 1929, returning to Hiroshima University. He published solutions to the first and second Cousin problems, and work on domains of holomorphy, in the period 1936-1940. These were later taken up by Henri Cartan and his school, playing a basic role in the development of sheaf theory. He continued to work in the field.
He was professor at Nara Women's University from 1949 to retirement at 1964. He received many honours in Japan.