Hanafuda Legends is a comprehensive, feature-rich browser adaptation of the traditional Japanese playing card game, Hanafuda. The game specifically implements the classic Koi-Koi ruleset for both casual and competitive play. To support new players, the game includes an interactive tutorial and in-game visual cheat sheets that explain card combinations, scoring rules (Yaku), and the monthly flower suits. Players can engage in single-player matches against AI opponents, generate private room codes for frictionless multiplayer with friends, or compete in an online ranked matchmaking system. Throughout gameplay, users can earn achievements and unlock digital gallery artworks based on their performance. Additionally, the platform offers multiple playable deck designs, allowing players to swap between classic historical artwork and custom contemporary illustrations.