Yukika Sohma, president of the nonprofit Association of Aid and Relief, died Saturday in Karuizawa, Nagano Prefecture. She was 96.
A funeral was held by family members. A memorial will be held later in Tokyo.
An activist for peace and democracy, Sohma promoted and established the association in 1979. It provides support for refugees as well as the removal of land mines in conflict areas. She was also the head of Japan-Korea Women's Friendship Association and was involved in other international and women's groups.
Sohma was the third daughter of Yukio Ozaki, a prominent Diet member starting in the 1890s who was a strong supporter of parliamentary democracy and a vocal critic of the government's militarism. He presented the 3,000 cherry trees to Washington that line the banks of the Potomac River to this day.