Etymology and distribution of 沓.

Kutsu 【沓】^{レベル3
About 50}  The Japanese surnames etymology dictionary.

Tochigi-ken . There is a 小口 surname. Tochigi-ken Shioya-gun Takanezawa-machi Tell Kashiwazaki that she was engaged in agriculture under groundbreaking. Tochigi-ken Shioya-gun Takanezawa-machi There is a tale that it was written as "Kojiku" in Kashiwazaki. Estimated in the Edo period. It is unknown if Kochi exists. Tochigi-ken Utsunomiya-shi was in the Edo period, Niigata-ken was in the Azuchi-Momoyama era. 小口 Oguchi reference.