Kai Chikanobu served as a bushō during the latter part of the Muromachi period and the Sengoku period. He was a retainer of the Aso clan and the fourth head of the Kai clan.
The Kai were an illegitimate branch of the Kikuchi clan and kokujin, or provincial landowners, in Kuraoka in Takachiho in Hyūga Province. Chikanobu was born as the son of Kai Shigetsuna.
Around 1514, after Aso Koretoyo lost in a conflict with Kikuchi Taketsune (Aso Korenaga) and fled from Higo Province, Chikanobu assisted him, enabling Koretoyo to restore his rights. Thereafter, Chikanobu served as the chief retainer of the Aso family. Koretoyo said that Chikanobu is there so there are no worries. At one time, once he became ill and suspended his service, the retainers lamented that, owing to the absence of Chikanobu, there was no progress in important meetings.
His son, Kai Chikanao (Sōun) inherited the headship of the clan.