The Tokugawa Gosanke, also called simply Gosanke, or even Sanke, were the most noble three branches of the Tokugawa clan of Japan: Owari, Kii, and Mito, all of which were descended from clan founder Tokugawa Ieyasu's three youngest sons, Yoshinao, Yorinobu, and Yorifusa, and were allowed to provide a shōgun in case of need. Wikipedia