Etymology and distribution of 庫井.

Kurai 【庫井】^{レベル1
Very rare}  The Japanese surnames etymology dictionary.

Akita-ken , Saitama-ken .

① Originated from the vicinity of the Yoshikawa river flowing through Akita-ken Yurihonjou-shi (formerly Koichi). A place name with a record since the Edo period. "Pebbles (coins)" in the Nanboku era era is a place where the same place is determined.

② In Toyama-ken , it is Nishi. Toyama-ken Takaoka-shi Originated from Koichi (Neyoshi) in the red circle of Fukuoka Town.