Cognomen Koshiishi (Koshiishi 
, โคชิอิชิ 
) , in all the world, is a very rare last name. The cognomen Koshiishi is habitual in Spain, where it is a very rare surname, Thailand, where it is an extremely rare surname, and Brazil. Not in comparison with a country's population, it most frequently occurs in Spain, Brazil, and the United States. More prevalently, Koshiishi is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Koshiishi | Brazil, Japan, China, United States, Spain |
| โคชิอิชิ | Thailand |