The Vale Tudo cards were part of a magazine insert trading card set put out by Gong Magazine in Japan. The set included other K-1, RINGS, Karate, and Kickboxing.
The set is mainly made up of actors and musicians but included a couple of sports inserts. Ring Kings being one of them. Ring Kings was dedicated to the world of MMA.
The Trading Card set consists athletes from multiple sports , with only one MMA athlete in their 375 card Base set, but includes several MMA signature cards.