Entering the big number - Oban-iri

...During the Keicho and Genna eras, they were stationed at Fushimi Castle, and during the Kanei era, they were stationed at Sunpu Castle. They have the oldest history among the guard positions (Oban, Shoinban, Page Group, Shinban, Kojunin Group, etc.), and guards were selected from those with good family backgrounds, and joining the Oban was considered an honor. The title Oban was also found among the guard positions of related clans such as the Gosanke and the Echizen Matsudaira clan.

*Some of the terminology that refers to "Oban-iri" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…慶長･元和のころには伏見城にも在番し，また寛永のころには駿府城にも在番した。番方(大番，書院番，小姓組番，新番，小十人組など)の職制中もっとも古い由緒をもち，番士は家筋の良いものから選任され，大番入りを名誉なこととした。なお，大番の称は，御三家や越前松平家など親藩の番方職制中にもみられる。…

※「大番入り」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報