Mathematician Heisuke Hironaka, Winner of Fields Medal, Dies at 94

The Yomiuri Shimbun

16:56 JST, March 19, 2026

Heisuke Hironaka, a professor emeritus at Kyoto University and a former Yamaguchi University president who won the Fields Medal in 1970, died on Wednesday. He was 94.

The Fields Medal is often referred to as the Nobel Prize for math.

Hironaka also nurtured younger generations and was involved in the creation of the Sansu Olympics, a math competition for children.

He was born in Yamaguchi Prefecture in 1931. He graduated from Kyoto University’s science department in 1954 and went on to serve as a professor at Columbia and Harvard University as well as the head of Kyoto University’s Research Institute for Mathematical Sciences. From 1996 to 2002, he was president of Yamaguchi University.

Hironaka specialized in algebraic geometry. In 1970, when he was a Harvard University professor, he was awarded the Fields Medal for the resolution of singularities of an algebraic variety. He authored many books, such as “Ikiru Koto Manabu Koto” (Living, studying) and “Gakumon no Hakken” (The discovery of study), and received the Order of Culture in 1975. He worked in education as well, nurturing young talent, and served as honorary chair of the Sansu Olympics, which encourages children to compete in math and thinking skills.

He enjoyed a long friendship with world-famous conductor Seiji Ozawa, who died in February 2024 at the age of 88. They published a book together titled “Yawarakana Kokoro o Motsu” (Having a soft heart). Hironaka’s wife, Wakako, 91, is a former member of the House of Councillors and once headed the Environment Agency (now the Environment Ministry).

The Fields Medal is awarded once every four years to young academics age 40 or younger. Three Japanese have won the medal. The other two are Kunihiko Kodaira, a professor emeritus at the University of Tokyo who won the medal in 1954 and died in 1997, and Shigefumi Mori, 75, the director-general of the Kyoto University Institute for Advanced Study and one of the medal recipients in 1990.

When Mori was a junior at Kyoto University, he heard a lecture by Hironaka, who was visiting from the United States, Mori said.

Hironaka “struck off some splendid diagrams and explained them to us, and I clearly remember it solved my questions instantly,” Mori recalled. “That lecture really drove me to pursue algebraic geometry.”