Family name イッコウ (Ikko 
, イッコウ ) , throughout the world, is quite a rare cognomen. The last name イッコウ is habitual in Japan, where it is quite a rare surname, Estonia, where it is a rare surname, and Malaysia. In absolute terms, it is commonest in Japan, Indonesia, and Malaysia. Likewise, イッコウ is the forename as well as the last name.