Tokyo — Kenzo Tange,

hailed as the architect of some of the 20th century's most beautiful structures and a mentor to a generation of groundbreaking Japanese designers, died Tuesday of heart failure at his home. He was 91.

Mr. Tange, who stayed active designing until he was 88, had been resting at his Tokyo home, said Kazuo Aso, a spokesman for his design office, Tange Associates.

Mr. Tange saw in the ashes of the Second World War a chance to create not just new buildings but new cities. His Peace Centre in Hiroshima, built four years after the U.S. atomic bombing in 1945, was designed to become the “spiritual core” of the city.

In the work considered his masterpiece — the twin gymnasiums designed for the 1964 Tokyo Olympics — he placed two comma-shaped buildings with sweeping roofs like upside-down ships' hulls so as to connect two busy Tokyo districts.

The jury that awarded Mr. Tange the prestigious Pritzker Prize in 1987 called him a leading theoretician of architecture and an inspiring teacher.

“His stadiums for the Olympic Games held in Tokyo in 1964 are often described as among the most beautiful structures built in the 20th century,” the jury said. “In preparing a design, Tange arrives at shapes that lift our hearts because they seem to emerge from some ancient and dimly remembered past and yet are breathtakingly of today.”

Later in his career, Mr. Tange took on international projects and designed buildings in China, Singapore, Australia, Malaysia, Nepal, Saudi Arabia, Iran, Kuwait, Nigeria, Italy, Yugoslavia and the United States.

Born in Osaka on Sept. 4, 1913, Mr. Tange's visions were often ambitious, including a plan to redesign the chaotic, haphazard streets of Tokyo.

“Architects today tend to depreciate themselves, to regard themselves as no more than just ordinary citizens without the power to reform the future,” Mr. Tange wrote. “I feel however, that we architects have a special duty and mission ... (to contribute) to the socio-cultural development of architecture and urban planning.”