Family name Koreyasu (Koreyasu 
, 是安 
) , in the entire world, is a very rare last name. The family name Koreyasu is characteristic of the United States, where it is an extremely rare surname, Brazil, and China. More prevalently, Koreyasu is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Koreyasu | Japan, Brazil, United States |
| 是安 | China |
| azai koreyasu samurai of the Sengoku period |
|