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Surname 亮一 (Ryoichi , 亮一 , Ryouiti) , in all the world, is quite a rare cognomen. The surname 亮一 is habitual in Japan, where it is quite a rare surname, Singapore, where it is a rare surname, and Cambodia, where it is a very rare surname. Measured by absolute frequency, it is commonest in Japan, China, and Indonesia. Much less frequently, 亮一 is the forename as well as the last name.