Yamaken-gumi
| Founded | 1961 |
|---|---|
| Founder | Kenichi Yamamoto |
| Founding location | Kobe, Japan |
| Years active | 1961–present |
| Territory | Kobe, Japan |
| Ethnicity | Japanese |
| Membership (est.) | ~800 |
The Fourth Yamaken-gumi (四代目山健組, Yondaime Yamaken-gumi) is a yakuza gang based in Kobe, Japan. It was the largest affiliate, followed by the Nagoya-based Kodo-kai, of the largest known yakuza syndicate in Japan, the Yamaguchi-gumi until 2015.