Cognomen 凯森 (Keson 
, 凯森 , Kaisen 
) , in the world, is quite a rare surname. The cognomen 凯森 is characteristic of Denmark, where it is quite a rare surname, Luxembourg, and Thailand, where it is a rare surname. Measured by absolute frequency, it is the most numerous in Japan, the United States, and Denmark. Also, 凯森 is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Keson | Germany, China, United States, Thailand, Poland |
| 凯森 | China |
| Kaisen | Japan, China, Thailand, United States, Denmark |
| Kaysen | Germany, Thailand, United States, India, Denmark |