Surname セイゴ (Seigo 
, セイゴ ) , across the world, is quite a common cognomen. The cognomen セイゴ is characteristic of Japan, where it is quite a rare surname, Singapore, where it is a rare surname, and Canada, where it is a very rare surname. Measured by absolute frequency, the name is most common in Japan, China, and the United States. Much less frequently, セイゴ is the forename as well as the last name.