Japanese Mahjong

4 players · you against three AI · one deal

1. 1

   Objective

   • Build a legal hand with at least one yaku. Dora, red dora and ura-dora add value but cannot supply that yaku. The first valid win ends the deal; if the wall runs out, settle ready-hand payments.
2. 2

   Setup

   • Use 136 Japanese tiles without flowers, including one red five in each suit. Each player starts with 25,000 points. The dealer receives 14 tiles and others 13. Reserve a 14-tile dead wall, reveal one dora indicator and allow at most four kong replacements. The round wind is East, and seat winds follow the current dealer.
3. 3

   Playing a turn

   • On your turn, draw one tile and discard one. Select a tile and confirm the discard. Matching copies retain separate physical identities.
   • A discard can complete a win, pung or exposed kong. Only the next player may chow three consecutive tiles of one suit. Resolve all responses before awarding the tile: wins outrank pungs and kongs, which outrank chows. Equal-priority claims follow seating order after the discarder.
   • Four matching tiles can form a concealed kong. A fourth tile can extend an existing pung into an added kong. Draw a replacement after any kong, then discard. Added kongs can be robbed for a win. Concealed kongs cannot. Kongs require an available replacement. After a chow or pung, discard before declaring a concealed or added kong.
   • After a chow or pung, you cannot immediately discard the called tile type. A chow also forbids swapping the sequence for one at its other end. Concealed kongs preserve a closed hand. Other calls open it.
4. 4

   Riichi and furiten

   • A closed hand in tenpai may declare riichi by a legal discard if the player has at least 1,000 points and the wall has at least four tiles. Pay a 1,000-point deposit. After riichi, discard only the drawn tile, or claim a legal win. This preset forbids further kongs after riichi. Ippatsu ends on any chow, pung or kong, or on the declarer's next discard.
   • If any current winning tile type appears in your own discard history, discard furiten prevents ron but permits tsumo. Passing a legal ron causes temporary furiten until your next draw. Passing ron after riichi causes furiten for the rest of the deal. Furiten checks every winning tile type, not just the current discard.
5. 5

   Scoring and ending

   • Calculate ron/tsumo payments from yaku, han and fu. Standard yaku include closed tsumo, tanyao, value honors, pinfu, seven pairs, all pungs, three-color sequences, straight, half/full flush and yakuman. Kongs reveal more dora indicators. Only a riichi winner reveals ura-dora. Dealer multipliers apply, and the winner receives riichi deposits.
   • The discarder pays ron. Three opponents share tsumo according to dealer status. Multiple ron declarations use head bump: the nearest player after the discarder wins. On an exhaustive draw, noten players share a total 3,000-point payment to tenpai players. All tenpai or all noten means no transfer. This independent single-deal preset returns unclaimed deposits after a draw.