It's not in Tokyo, but the few hours by train that it will take you to get to the SANAA (Kazuyo Sejima and Ryue Nishizawa) designed 21st Century Museum of Contemporary Art in the city of Kanazawa will probably be an escape worth embarking on.

LINK: 21st Century Museum of Contemporary Art
LINK: SANAA

21ST CENTURY MUSEUM OF CONTEMPORARY ART
1-2-1 Hirosaka
Kanazawa, Ishiwaka
920-8509

t. 76.220.2800
f. 76.220.2802