Koiwai 【古岩井】3 The Japanese surnames etymology dictionary.
① things . From timber (Zymok). Toyama-ken Himi-shi tells me that it was Meiji new family name by handling timber. Hokkaidou Hokuto - shi Mitsuishi tells Akita - ken 's out. Saga-ken Saga-shi lumber (Zymok) is a place name with a record since the Edo period. Good neighbor . Fukuoka-ken Tagawa-gun Kawasaki-machi Kawasaki is based.