Etymology and distribution of 五十井.

Ikai 【五十井】^{レベル3
About 300}  The Japanese surnames etymology dictionary.

Hyougo-ken Akashi-shi · Kita-ku, Kobe City. 諫早 's variant.

Isoi 【五十井】^{レベル3
About 300}  The Japanese surnames etymology dictionary.

Toyama-ken , Kumamoto-ken , Hokkaidou .

① things . From the net. Toyama-ken Meiji new family name using "thread", "Oka" by disassembling "net" by the fisherman of the Imizu-shi .

② 井戸岡 there last name. Kumamoto-ken Kikuchi-shi Asahi It is based in Ichi. Tell him that he was engaged in agriculture in the same area. Estimated in the Edo period. Shiga-ken Kusatsu-shi Shimogi town is based. 井戸岡 Idooka reference.

③ Kagoshima-ken Ooshima-gun Isen-chou Birth of Itochi name. A place name with a record since the Edo period. "Thread" of Thameski name is used.