Nagashi mangan (流し満貫) is a special yaku. Unlike all other possible hands, this yaku emphasizes the discards, rather than the hand itself.
Scoring nagashi mangan
This yaku has specific conditions for qualification:
- The hand must play all the way to ryuukyoku with nobody winning earlier.
- Every discard of the player must be a terminal or an honor tile.
- The player may not have called any tiles. The EMA 2012 rules allow a player to meld concelaed kantsu and still score nagashi mangan, most other rulesets do not allow even this.
- No tiles may have been called from the player's own discard pile.
Upon reaching ryuukyoku, the player does not need a hand in tenpai.
As the name implies, successful execution of nagashi mangan rewards the player in the amount of a mangan tsumo. If multiple players win with nagashi mangan, the different tsumo payments occur independently of each other.
Timing at ryuukyoku
When the wall is empty and the last discard has not been called for a win, special rulesets may differ on the exact procedure to score nagashi mangan.
- Some rules score nagashi mangan like a win, before players reveal tenpai hands. Honba increase the payment, and the winner collects any riichi sticks on the table. The noten penalty is cancelled and noten riichis are not punished with chombo. Hand progression depends on whether East has won with nagashi mangan. This variant is used in the EMA rules.
- Some rules merely score nagashi mangan like a bonus payment, not as a win. Nagashi mangan happens at the same time as players reveal tenpai hands. The noten penalty is cancelled and replaced by the nagashi mangan payment, but that payment is not affected by honba or riichi sticks. Chombo takes precedence over nagashi mangan payments. If there is no chombo, then hand progression depends on whether East is tenpai. This variant is chosen in the Tenhou.net rules.
- Nagashi mangan in Japanese Wikipedia