Etymology and distribution of 研磨.

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

Saitama-ken , Ishikawa-ken , Kagoshima-ken . Terrain . 坂下 's variant. Saitama-ken Iruma-shi It was in the Konbata during the Edo period. 坂下 Sakashita reference.

※ Saitama-ken Tokorozawa-shi Sakanoshita (Sakanoshita) is a place name with a record in the notation of "Sakanoshita" in the Edo period. The place name was also written as "Sakashita".

※ Kagoshima-ken Ichikikushikino-shi Distributed in Osato. In the same area there was a gate of Sakanoue gate in the Edo period.