Yu-Gi-Oh! Duel Monsters II: Yamikai Kettouki is a video game for the Game Boy Color, the sequel to Yu-Gi-Oh! Duel Monsters. Although the gameplay is still much simpler than the OCG, this game introduced 355 new cards, for a total of 720 (in contrast with the 365 total cards of its predecessor). Trap and Ritual Cards were first included in this game.