Ikai 【伊海】3 The Japanese surnames etymology dictionary.
② variant of the 城戸 . Nagasaki-ken Tsushima-shi tells us that Tokubara-machi of Nagasaki-ken Tsushima-shi renamed from Kurido surname on October 18, 1601 (Kei 6th year) from Tsutsumi Souchi of the Tsushima Fuchu lord of the clan office. The pronunciation is Kid. 城戸 reference.