Jodai (Castellan) (城代)
The jodai is a person who took care of a castle in the absence of the lord. There are other descriptions such as Rusuigashira and Orusui. In the Sengoku Period (Period of Warring States) (Japan), a vassal was referred to as jodai when he was assigned to take care of a castle directly controlled/managed by a daimyo (Japanese territorial lord) and administrative affairs and protect the castle from attacks.
The Edo bakufu established four jodai for Sunpu-jo Castle, Nijo-jo Castle, Fushimi-jo Castle, and Osaka-jo Castle (the jodai for Fushimi-jo Castle was discontinued in 1619). When its feudal lord was away to Edo due to the Sankinkotai (a system under which feudal lards in the Edo period were required to spend every other year in residence in Edo), a vassal who had to take care of the castle during the absence of the lord was particularly called Jodai-garo (usually, a chief retainer was assigned to exercise his duties).