Tochigi (tōˈchĭgē) [key], prefecture (1990 pop. 1,935,186), central Honshu, Japan. Utsunomiya (the capital), Ashikaga, Oyama, Kanuma, and Sano are the chief cities. Its many fertile river plains yield rice, wheat, and tobacco. Cattle are raised and copper and manganese are mined. Automobiles, ceramics, processed foods, silk, and electrical appliances are also produced there. In the mountainous area of W Tochigi is Nikko National Park.