Surname Kasei (Kasei 
, Касей 
) , globally, is a common family name. The family name Kasei is habitual in Japan, where it is quite a common surname, Kyrgyzstan, where it is a rare surname, and Tanzania, where it is a very rare surname. In absolute terms, it most frequently occurs in Japan, Tanzania, and China. Likewise, Kasei is the forename as well as the last name.