When Tokugawa Ieyasu reunited Japan in 1603 and established the Tokugawa Shogunate, with its headquarters at Edo, he installed members of his own Tokugawa clan as rulers of Mito and only two other domains, present-day Nagoya and Wakayama. These three cadet lines (known as Gosanke ???) were eligible to supply an heir in case any ruling shogun failed to produce one. They were thus among the most loyal of the Tokugawa loyalists. However, the Mito School of fiercely chauvinist Confucian scholars also helped to redefine the Japanese nation in a way that provided the ideological foundation for enhancing imperial power during the Meiji Restoration and its aftermath. http://wikitravel.org/en/Mito