Tofu was introduced to Japan during the Nara period (late 8th century) by Zen Buddhist monks, who initially called it . A firm variation of tofu was introduced in Tosa Province, today's Kochi Prefecture, by a Korean doctor and prisoner of war following the Japanese invasions of Korea (1592–1598). Much of tofu's early use in East Asia was as a vegetarian substitute for meat and fish by Buddhist monks, especially those following Zen Buddhism.