Etymology and distribution of 是山.

Koreyama 【是山】^{レベル2
About 10}  The Japanese surnames etymology dictionary.

Hokkaidou , Toyama-ken , Kanagawa-ken . Terrain . From the bamboo and island like land. It was in the Azuchi Momoyama period in Toyama-ken Oyabe-shi . The pronunciation is Sasajima. Aichi-ken Chita-gun Minamichita-chou Shinojima is a place name with a record since the Asuka period. Ishikawa-ken Kanazawa-shi Marunouchi was in the Edo era at the Kaga clan in the Clan office. The same clan says that Fukui - ken Eastern (formerly Echizen Country) comes out. 笹島 Sasajima reference.