Family name Масааки (Seiyo 
, Masaki 
, Masaaki 
) , in all the world, is a common surname. The surname Масааки is habitual in Tanzania, where it is quite a rare surname, Japan, and Kenya. Not in comparison with a country's population, this name is the most popular in Tanzania, Japan, and China. Likewise, Масааки is the forename as well as the last name.