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strategy riichi

Dama

ダマ
(だま)

By Kenji Tanaka · Updated

Definition

Dama is the quiet route: sitting in tenpai with a closed hand and declining to declare riichi. No sideways tile, no point stick, no warning. Opponents keep discarding freely, which makes your winning tile easier to catch. The price is steep, though. You give up the riichi han, ippatsu, and ura dora, so a dama win is usually far cheaper than the same hand with riichi. It earns its keep when your hand already has a yaku, when you want the freedom to reshape your wait, or when hiding your strength matters more than maximizing it.

Dama

What counts as Dama

Dama (ダマ) is a short form of damaten, referring to the strategy of waiting silently for a winning tile while in tenpai without declaring riichi. The hand remains closed and concealed, with no public announcement of the waiting condition.

Dama, explained

Dama represents a fundamental strategic choice in mahjong that contrasts sharply with the more aggressive riichi declaration. When a player reaches tenpai, the state of being one tile away from winning, they face a critical decision: declare riichi to lock their hand and announce their waiting condition, or remain silent and continue drawing tiles without revealing their status.

Strategic Considerations

The primary advantage of dama is concealment. By not declaring riichi, you maintain ambiguity about your hand’s composition and which tiles you’re waiting for. Opponents cannot use the riichi declaration as information to adjust their discard strategy. This unpredictability can make it harder for other players to avoid feeding you winning tiles.

Additionally, dama allows for flexibility in hand development. While riichi locks your hand structure, you cannot change the tiles you’re waiting for, dama technically permits you to pivot your wait if you draw the right tile. However, this flexibility is often theoretical, as most hands in tenpai cannot meaningfully change direction.

Risks and Drawbacks

The primary disadvantage of dama is the value you give up. Declaring riichi is itself a 1-han yaku, and it unlocks two more sources of value: ippatsu (an extra han for winning within one uninterrupted go-around) and ura dora (hidden bonus indicators revealed only on a riichi win). A dama hand touches none of these, so the same tiles usually score substantially less won silently than they would with riichi declared.

Dama also sacrifices the riichi declaration as a pressure tool. A riichi announcement forces opponents into defensive play; staying silent forfeits that influence over the table.

When Dama Is Appropriate

Dama proves most effective in specific situations:

  • Early game: When few tiles have been discarded and your hand composition is less transparent
  • Low-value hands: When the riichi bonus represents a significant portion of your expected winnings
  • Defensive positions: When you’re significantly behind in points and need to win without triggering defensive play
  • Complex situations: When your hand’s waiting tiles are ambiguous or unusual

Walking through Dama

A player reaches tenpai with tanyao already in the hand, waiting on a mediocre kanchan. Rather than declaring riichi and locking that narrow wait, they choose dama. Two turns later they draw a tile that lets them reshape into a wide ryanmen wait, something a riichi hand could never do, because riichi freezes the hand. When they win shortly after, the hand scores less than a riichi version would have (no riichi han, no ippatsu, no ura dora), but the improved wait is what let it win at all.