Riichi Mahjong

Riichi Mahjong is the Japanese variant famous for its depth: you declare riichi on a concealed ready hand, chase yaku patterns, and read the table to defend. Scoring uses the complete open-source @kobalab/majiang-core rules engine — every yaku from tanyao to yakuman, with fu and han calculated exactly. Note: this MVP does not track ippatsu or ura dora. Play against three AI opponents in your browser, with the score of every hand explained in full.

• ▸You need at least one yaku to win — riichi, tanyao, yakuhai, pinfu and more
• ▸Riichi: declare on a concealed tenpai hand and bet a 1,000-point stick
• ▸Dora indicators add fan to matching tiles
• ▸Furiten blocks you from winning on a discard you have already discarded
• ▸Exact fu/han scoring with the majiang-core engine, yakuman included