Furiten in riichi mahjong is a state in which a player has discarded a tile that would have otherwise completed his hand.
A player who is furiten cannot win on an opponent's discard, but can only win by self-drawing the needed tile. Furiten rule is the crux of riichi mahjong.
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.
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. The state of temporary furiten ends next time the player draws or claims a tile.
However, if the player has declared riichi he remains temporarily furiten until the end of the hand.
A player is never considered furiten on a self-drawn tile.
Furiten -- example #1:
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
The player is waiting 1-4 circles. A discarded 7 circles does not make the player furiten.
The player is furiten only if the discards contain one of the waiting tiles: 1 or 4 circles.
Furiten -- example 3:
Let's suppose that a player has the following hand:
The player is waiting for three tiles: 4 and 7 circles and red dragon. If another 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.
In a tournament the chombo penalty is 20000 points which are deducted from the players overall tournament score after the game is finished and after the uma is added to the players'
scores. Outside of the tournaments, the chombo penalty is a reverse 'mangan' payment: 4000 to East, 2000 to other players.
If the offending player is East, 4000 is paid to each of the other players.
The following offences are subject to chombo penalty:
Invalidly declaring a win and showing the tiles. The win can be invalid because the hand is not a valid winning hand or because the declaration was not valid.
Declaring riichi on a hand that is not waiting. This is determined only in case of a drawn game.
Making an invalid concealed kong after declaring riichi (determined only if the offender declares a win or in case of a drawn game).
Attempting to claim a tile after the hand has been declared a dead hand.
Play cannot continue due to a mistake of a player. E.g. too many tiles were revealed for the game to continue fairly.
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.
3.4.7 Dead hand
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 irregularities result in a dead hand:
Attempting to declare riichi on a open hand
Too few or too many tiles on the hand
Making an invalid kong, pung or chow.
3.4.9 When a win is declared
When a hand ends with one or more playes declaring a win, the hand(s) are scored. Only winners receive payment.
If there are more than one possibility for which way the winning tile finishes the hand, the highest-scoring possibility is always chosen.
A player winning on a self-draw, receives payment from the three opponents.
A player whose discard results in one or more winning declarations, pays the full value of each hand to the winner.
East receives more points for a win, but also pays more in case of an opponent's self-draw.
When East wins the hand (whether more players win or not), a counter is placed on the table at East's right-hand side.
A counter is placed on the table at East's right-hand side after a hand where East declared a win and after an exhaustive draw.
Each counter on the table increases the value of a winning hand by 300 points. In case of self-draw, the payment is shared, so each opponent pays 100 points for each counter to the winner, in addition to the standard payment for the hand.
All counters are removed after a hand where another player than East declared a win, and East did not.
3.4.11 Dealer rotation
After the end of a hand, it is determined whether East stays East or whether the privilege proceeds to the next player.
East stays East if he declares mahjong or if he is tenpai when there is an exhaustive draw.
If there are multiple winners, East stays East if he was one of the winners.
Otherwise, the deal rotates, and the player who was South now becomes East, while West becomes South, North becomes West and East becomes North.
3.5 Continuation of the game
When the dealer rotation is resolved, the tiles are shuffled face-down, and a new hand begins.
When the player who began the game as East, becomes East again after all opponents have had at least one hand as East, the South round begins.
When the player who began the game as East, becomes East again after all opponents have had at least one hand as East in the south round, the game ends.
3.6 End of the game
When the south round ends, and the game is over, the winner is the player with the most points. It is of no consequence how many individual hands were won, the total sum of points determines the winner. Ties may occur.
Any riichi bets remaining on the table are collected by the winner; the points are split in case of a tie.
Agari yame is not allowed. This is a rule that would allow East to end the game early if he wins the .nal hand and is leading the game.
3.6.1 Winner bonus
At the end of the game an extra bonus/penalty (uma) is applied to the scores. The two best ranked players receive a bonus from the two lowest ranking players in the game, according to this scheme: Winner receives 15,000 points, second ranked player receives 5,000 points, third ranked player is penalized with -5,000 points and the last player is penalized with -15,000 points.
If there is a tie, the points for the relevant places are split between the tied players. E.g. if two players are tied at the .rst position, each gets a bonus of 10,000 points.