Koshogumi (page corps) (小姓組)

Koshogumi (page corps) was an organization in the Edo bakufu and one of the bankata which took charge in the military affairs. A similar organizations were called Gobankata (including koshogumi, shoinban [the castle guards], Shinban [New Guard], Oban [a group of guards in the Edo shogunate], Kojunin [Escort Guard]), in which koshogumi and shoinban were collectively called ryoban. Incidentally, the kosyogumi was different from kosho (pageboy) in the general conception and was purely a combat troop.

It was established in November, 1606 and six people were appointed as Banto (heads of the group), namely Tadamoto MIZUNO, Masafuyu KUSAKABE, Masatake NARUSE, Noritaka OKUBO, Masanari INOUE, and Shigemune ITAKURA.

Their duty was in the wartime to serve as 直掩備 and cavalry for Shogun under the troops of hatamoto (direct retainers of the shogun), and in the peacetime to guard of Shogun in the castle. Together with shoinban, it was a kind of bodyguard in nature, so qualifications to become a Banshi (a samurai serving as a guard in the Edo period) were limited based on the Kakaku (family status) and post of his father. Therefore, the status of Banshi was regarded as higher than the other bankata, thus the Banshi was likely to get higher post. It was under the management of wakadoshiyori (junior councilor) and the yakudaka (salary paid in accordance with the rank of one's post) of Banto was 4,000 koku (approximately 0.72 million liters of crop yields). There were six groups in total, each consisted of Banto, one Kumigashira (the leader) and fifty Banshi. There were additional four groups in nishi no maru (a castle compound to the west of the main compound).