What is Aka Dora? Red 5s in Riichi Mahjong
Aka dora — the red-tinted 5s — quietly inflate scores in modern riichi mahjong. Here is how they actually work and how they differ from regular dora and ura dora.
What is aka dora?
Aka dora (赤ドラ, literally "red dora") are special tiles painted red instead of the usual colour, swapped into the wall in place of an ordinary tile of the same kind. The standard set is three tiles: one red 5m, one red 5p and one red 5s. Each red five in a winning hand counts as 1 han, exactly like a regular dora — but unlike regular dora, the bonus is intrinsic to the tile itself; no indicator is needed.
How is aka dora different from regular dora?
Regular dora is indicated by a tile flipped in the dead wall: whatever tile that indicator "points at" (1m → 2m, 9p → 1p, North → East, etc.) becomes the bonus tile for that hand. Aka dora is fixed: the tiles themselves are red, so any time a red five lands in a winning hand it scores, regardless of indicators. Both forms add 1 han per tile, both stack freely, and neither is a yaku on its own — but their detection rules are completely different.
How many aka dora are in a standard set?
Most modern rule sets ship three: one red 5m, one red 5p and one red 5s, with the regular 5 of each suit becoming a 3-of-4 instead of 4-of-4. Some tenhou-style 4-player rule sets use four (two red 5p — common in lobbies that want even higher scoring), and a few stricter rule sets ship zero. Always check the table rule before play.
Do aka dora count as a yaku?
No — aka dora is a han bonus, not a yaku, exactly like regular dora and ura dora. The winning hand still needs at least one real yaku to be valid. "Three aka dora and no other yaku" is a no-yaku hand and cannot win, even though three han sounds like a lot.
Which rule sets include aka dora?
Modern Japanese rule sets almost always include aka dora — Tenhou, Mahjong Soul, M-League and most online lobbies enable them by default. Classical tournament rules (such as some WRC variants) often disable them to keep scoring tighter. The two big effects: aka dora bumps average hand value by roughly 0.3-0.6 han per win, and it makes 5s much more valuable to keep in hand than 1s or 9s of the same suit.