Usui 【碓水】3 The Japanese surnames etymology dictionary.
Hyougo-ken , Hokkaidou . There is a surname including "plum". Hokkaidou Tokachishi-chou Taiki-chou In Tsuyoshi tells that he emigrated from Tottori-ken around 1922. In Toyama-ken Namerikawa -shi it is Umetsugu. Toyama-ken Namerikawa-shi Okubo is based. Tell him that he was engaged in agriculture in the same area. Estimated in the Edo period.