Ooyamaneko.net

A hand can end in three ways: by exhaustive draw (no-one declares a win after the discard after the last tile), by abortive draw or by one or more players declaring a win. Chombo results in a redeal and does not count as a hand.

The last tile in the wall can only be claimed for a win, not for a kong, pung or chow. In case a kong is declared at the second-to-last tile, the replacement tile becomes the last tile. It is not allowed to declare a concealed kong on the last tile.

An exhaustive draw occurs if no-one declares a win after the discard after the last tile. The 14 tiles of the dead wall are not used. After an exhaustive draw the noten players (a player who can’t or won’t show a tenpai hand) pays a penalty to tenpai (waiting) players (players who show a tenpai (waiting) hand). The total noten penalty amounts to 3000 points. E.g. if three players are tenpai, the noten player pays 1000 to each, whereas if only one player is tenpai he receives 1000 points from each of the noten players. A player is not considered tenpai if he is waiting only for a tile of which he already has 4. A player is still considered tenpai if all his waiting tiles are visible among the discards and declared sets. Players who have declared riichi are obliged to show their tenpai hands in case of an exhaustive draw. After an exhaustive draw, a counter is placed on the table at East’s right-hand side.

After an abortive draw no noten penalty is payed, and players who have declared riichi are not obliged to show their tenpai hands, except in case of four riichi declarations. After an abortive draw, a counter is placed on the table at East’s right-hand side. Abortive draw can occur in four ways:
• A player who after his first draw in the uninterrupted first set of turns has at least nine different terminals and honours may declare an abortive draw.
• No-one wins after the discard after the fourth kong, and the four kongs do not belong to the same player.
• All players discard the same wind in the first uninterrupted set of turns.
• All four players have declared riichi, and no-one declares a win on the discard on which the fourth player declares riichi. All players are obliged to show their tenpai hands.

In case of a drawn game (whether by exhaustive draw or abortive draw), any riichi bets stay on the table to be claimed by the next player who declares a win.

If a waiting player can form a mahjong hand using one of his previous discards, he is furiten and is not allowed to claim a win on a discard.
A player who is furiten can choose to change his hand to avoid being furiten (except if he has declared riichi).
A player who is furiten, can still win on a self-drawn tile.
A player who fails to claim a win on a discard that completes a mahjong hand, is temporarily furiten, even if the passed tile gives him no yaku, and he cannot claim a win on a discard in the current set of turns. If the set of turns is interrupted by claims for kong, pung or chow, the player is no longer temporarily furiten. The state of temporary furiten always ends when the player draws a tile, i.e. no player is ever considered furiten on a selfdrawn tile.

Furiten – example 1. If a waiting player can form a mahjong hand using one of his previous discards, he is furiten and is not allowed to claim a win on a discard, even if the hand completed with the previous discard is without a yaku.
Consider a player with the following hand:
  
The player has a three-sided wait for 3-6-9. The player is furiten if any of the three waiting tiles are among his discards.

Furiten – example 2. Consider a player with the following hand:
    
The player is waiting 1-4 circles. A discarded 7 circles does not make the player furiten. Only if one of the waiting tiles (1 or 4 circles) are among the discards is the player furiten.

Furiten – example 3. Consider a player with the following hand:
   
The player is waiting for three tiles: 4 and 7 circles and red dragon. If the player has discarded one of these tiles, he is furiten.

Severe offenses are punished by chombo, after which there is a re-deal of the current hand. If a win is declared at the same time as a chombo occurs, the chombo is voided.
The chombo penalty is the same size as a mangan payment: 4000 to East, 2000 to other players. If the offending player is East, 4000 is payed to each of the other players.
The following offences are subject to chombo penalty:
• invalidly declaring a win
• declaring riichi on a hand that is not waiting (determined only in case of a drawn game)
• making an invalid concealed kong after declaring riichi (determined only if the offender wins or in case of a drawn game)
• exposing more than five tiles from the wall, the dead wall, the player’s or opponents’ hands
• claiming a tile after the hand has been declared a dead hand

After a chombo riichi bets are returned to the players who declared riichi, and there is a re-deal. No counter is placed, and the dealer does not rotate.

Some irregularities that are not punished by chombo result instead in a dead hand. A player who has a dead hand is not allowed to declare a win, kong, pung or chow, and can never be considered tenpai.
The following irregularites result in a dead hand:
• too few or too many tiles on the hand
• exposing tiles from an opponent’s hand or from the dead wall
• making an invalid kong, pung or chow

Minor irregularites are generally not penalized. Please refer to Section 5 on Etiquette and tournament rules.