Gosankyō in the context of Tokugawa shōgun

Shinpan (親藩) was a class of daimyō in the Tokugawa Shogunate of Japan who were certain relatives of the Shōgun.

While all shinpan were relatives of the shōgun, not all relatives of the shōgun were shinpan; an example of this is the Matsudaira clan of the Okutono Domain. Non-daimyō relatives, such as the Gosankyō, were also known as kamon – thus the shinpan lords were alternatively known as kamon daimyō (家門大名). Shinpan included the Gosanke, the Matsudaira clan of Aizu and the Matsudaira clan of the Fukui Domain. These branch families were created after the 1600 Battle of Sekigahara; there were 23 shinpan domains, producing a total of approximately 2.6 million koku of rice. Because they were family and thus could wield informal power, they were not permitted to hold official positions in the bakufu. These families could also provide a shogunal successor if necessary.

The Tokugawa Go-san-ke (徳川御三家, "the Three Houses of the Tokugawa"), also called simply Go-san-ke (御三家, "the Noble Three Houses"), or even San-ke (三家, "the three houses"), 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. In the Edo period the term gosanke could also refer to various other combinations of Tokugawa houses, including (1) the shogunal, Owari and Kii houses and (2) the Owari, Kii, and Suruga houses (all with the court position of dainagon).

Later, Gosanke were deprived of their role to provide a shōgun by three other branches that are closer to the shogunal house: the Gosankyō.

The Shōgitai (彰義隊, "Manifest Righteousness Regiment") was an elite samurai shock infantry formation of the Tokugawa shogunate military formed in 1868 by the hatamoto Amano Hachirō [ja] and Hitotsubashi Gosankyō retainer Shibusawa Seiichirō [ja] in Zōshigaya, Edo (now Tokyo). The Shōgitai took a large part in the battles of the Boshin War, especially at the Battle of Toba–Fushimi, and, after being assigned the defence of Kan'ei-ji temple, the Battle of Ueno, where they were nearly annihilated.

After the Battle of Ueno, some surviving Shōgitai fled north, eventually joining the rebels of the Ezo Republic. Following the defeat of Ezo, most of the few remaining former Shōgitai settled in Hokkaido as tondenhei. Among the survivors was Toyohara Chikanobu, who later achieved fame as a master nishiki-e artist.