Dora are designated bonus tiles: in an ordinary winning hand, each dora adds one han on top of the yaku already present. They are not counted on a genuine yakuman. The active dora is set by a dora indicator (ドラ表示牌) turned face up on the dead wall, and the dora itself is the tile that follows that indicator in sequence. Numbers wrap around (a 9-man indicator makes 1-man the dora), winds cycle East to South to West to North, and dragons cycle white to green to red.
There is always at least one dora indicator, and every completed kan adds another. Under Tenhou rules, an ankan indicator appears immediately, while a daiminkan or shouminkan indicator normally appears after the following discard. A chained kan first reveals the pending indicator. WRC 2025 reveals every kan-dora before the discard and uses no red fives. Riichi winners also reveal uradora.
Dora can move a hand across a limit tier, but keeping one must be weighed against shanten, ukeire, yaku and discard danger. Regardless of their number, dora can never make a hand legal without at least one yaku.