Cognomen セイジ (Seiji 
, セイジ , Seizi 
) , throughout the world, is a common last name. The cognomen セイジ is habitual in Japan, where it is quite a common surname, Taiwan, where it is a rare surname, and Greece. Not in comparison with a country's population, this name is the most popular in Eastern Asia, particularly Japan, China, and Taiwan. Much less frequently, セイジ is the forename as well as the last name.