Sanma, or three-player mahjong, is a variation of Riichi mahjong. Besides having three players instead of four, the core differences are as follows:
- Your starting score is 35000 instead of 25000.
- Calling chii is disallowed.
- The 2-8 manzu tiles
are removed from the game. 
and 
as dora indicators now indicate each other as dora. - The north wind tile
acts as nukidora: they can be declared (with the "Pei" button) and put aside for +1 extra han, which (like dora) does not count as yaku. Dora applies: every 
dora indicator adds 1 to the extra value of each . You can still use north winds to form your hand, but you will not get the extra han. - Upon declaring a north wind, you draw a replacement tile from the dead wall (the dead wall now has 8 draws to accommodate for this). Winning on this replacement tile does not grant rinshan.
- You can win off another player's nukidora declaration, like chankan, but this does not grant chankan. Nukidora declarations do not affect furiten.
- The dora indicator is now the fifth tile from the end of the dead wall, instead of the third tile, to account for four extra replacement tile draws.
- There is tsumo loss: for example, a non-dealer mangan is paid 4000 from the dealer and 2000 from the non-dealer, for a total of 6000 instead of the typical 8000.
