Damaten
Damaten 「黙聴」 (or "hidden tenpai") is a closed tenpai hand that has not called riichi. Typically, a dama hand will have a yaku without riichi; otherwise, menzen tsumo (or another circumstantial yaku) would be needed to win. An older term yamiten 「闇聴」 refers to the same thing.
Usage
There are many reasons to dama:
- When the call for riichi wouldn't increase the hand's value by itself. For example, a haneman is scored if you have 6-7 han. If you have an 6 han hand, the +1 han for riichi wouldn't increase the score. Declaring riichi could still increase score with a tsumo, ippatsu, and/or ura dora, but these aren't reliable.
- When the hand is valuable. Because players will often defend against a riichi hand, declaring riichi will generally lower your hand's win rate. So if your hand is already a guaranteed mangan or higher, you may wish to dama to get the existing value. Plus, once mangan is reached, each han afterwards has reduced value.
- When points do not matter. If you are far in the lead, dama can be used to increase your win rate (thus, ending the game faster). If the game is in all last, and winning with riichi wouldn't change your placement, dama can also be considered.
- When you wish to change your hand. Riichi locks your hand in, preventing you from upgrading the wait or gaining yaku. If your hand has many upgrades, you may wish to dama.
- When the hand is bad. You might get to tenpai on what would be a riichi-only bad wait hand and decide it's not worth it. If someone else reaches tenpai, you can abandon the hand.
That being said, you should not overuse dama. Riichi's +1 han is valuable, since each han below 4000 will roughly double your score. Plus, you can get even more han from ippatsu and ura dora. See riichi strategy for more details.
Game examples
- Damaten in Japanese Wikipedia
- Multiple instances where damaten was employed.