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.
Rice production in Japan
Rice production is important to the food supply, with rice being a staple part of the Japanese diet. Japan is the ninth largest producer of rice in the world. The rice seasons in Northern Japan last from May–June to September–October. In central Japan, it is from April–May to August–October. In southern Japan the rice season is from April -May to August–September. About 85% of the 2.3 million farms in Japan plant rice yearly. Improved varieties of japonica rice are grown in almost all prefectures in the country. The most widely planted variety is Koshihikari.