Imizu 【射水】3 The Japanese surnames etymology dictionary.
① Aichi-ken Okazaki-shi Origin of the Iwatsu (Iwazu) town. A place name with a record since the Muromachi period. The place name was also called "Iwatsu", "Iwato", and the last name "Iwato". 岩戸 reference. Okayama-ken Okayama-shi Kita Ward Marunouchi was in the Edo period in the Clan Okayama of the Clan office.