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. To score nagashi mangan,
- 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, and
- no tiles may have been called from their 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. The honba count increases the payment normally. 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 have nagashi mangan happen before players may reveal tenpai hands. 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 have nagashi mangan happen at the same time as players reveal tenpai hands. The noten penalty is still cancelled, but hand progression depends on whether East is tenpai. This variant is chosen in the Tenhou.net rules.