Surname Riku-Kai (Riku-Kai 
) , worldwide, is a very rare cognomen. The last name Riku-Kai is habitual in Eastern Asia, particularly Japan, where it is a very rare surname. Predominantly, Riku-Kai is the forename as well as the last name. Parts of the name also exists independently as a first name Riku, and a first name Kai.
| VARIANT | COUNTRY |
|---|---|
| Riku-Kai | Japan |