Japanese Nobel Winners Sakaguchi, Kitagawa Attend Awards Ceremony

By Naomi Nagao / Yomiuri Shimbun Staff Writer

15:27 JST, December 11, 2025

STOCKHOLM — Two Nobel Prize winners from Japan received their medals and diplomas from Sweden’s King Carl XVI Gustaf at the awards ceremony in Stockholm on Wednesday.

Shimon Sakaguchi, 74, is a distinguished honorary professor at the University of Osaka. He won the Nobel Prize in Physiology or Medicine for his discovery of regulatory T (Treg) cells necessary for maintaining immune tolerance.

Susumu Kitagawa developed new porous materials called metal-organic frameworks (MOFs), paving the way for efficient storage and transport of targeted gases. Also 74 years old, Kitagawa is a distinguished professor at Kyoto University who won the Nobel Prize in Chemistry.

At the awards ceremony, which was held in a concert hall, the Nobel committee praised Sakaguchi for discovering one of nature’s most elegant balancing mechanisms. For Kitagawa, the committee highlighted his work developing flexibly structured MOFs, materials capable of varying their structure upon demand.

The two winners shook hands with other laureates and fellow researchers. “I’m deeply grateful to receive such an award,” said Sakaguchi to reporters. “I believe this is a special day in my life.”

After the ceremony, a banquet was held at a city hall where the two enjoyed a meal while conversing with members of the Swedish royal family.

There are now 30 individual Nobel laureates from Japan, including three with U.S. citizenship. The organization known as Nihon Hidankyo, formally called the Japan Confederation of A- and H-Bomb Sufferers Organizations, received last year’s Peace Prize.