Tōhoku region
Tōhoku was traditionally considered the granary of Japan because it supplied Sendai and the Tokyo-Yokohama market with rice and other farming commodities. Tōhoku provided 20 percent of the nation's rice crop. The climate, however, is harsher than in other parts of Honshū due to the stronger effect of the Siberian High, and permits only one crop a year on paddy fields.
Japonica rice
Japonica rice ("O. sativa" subsp. "japonica"), sometimes called sinica rice, is one of the two major domestic varieties of Asian rice. Japonica rice is extensively cultivated and consumed in China, Japan, Korea, and Taiwan, whereas in most other regions is the dominant type of rice.