Ooyamaneko.net

Only winning hands are scored.
All players at the table are responsible for ensuring that winning hands are scored correctly and to the maximum points. When there are several ways to score the hand, the highest-scoring possibility must always be chosen.
The score can be corrected as long the hand is still intact or if all players agree.

First find the number of han: add the number of han given by the yaku (at least one), the number of dora tiles, kan dora tiles, and in case of a riichi winning hand the number of ura dora tiles. This sum is the han value of the hand.

Then calculate the base value of the hand:
• For hands worth less than five han, count the number of minipoints (fu) and round it up to the next ten. (E.g. 32 minipoints are rounded up to 40). In case of a seven pairs hand, the hand is worth 25 minipoints and is not rounded up.
The minipoints are then doubled for each han, and doubled two more times, giving the base value of the hand. This base value is limited to 2,000 points.
A base value of 1920 points, being close to mangan, is rounded up to 2,000 points.
• For hands with five or more han, the minipoints are irrelevant. The base value is given in the following table:

Han	Name	Base value
5	Mangan	2000
6, 7	Haneman	3000
8, 9, 10	Baiman	4000
11 and more	Sanbaiman	6000

• For yakuman hands, the base value is 8000.
There is no counted yakuman: a hand worth 13 or more han but not having a yakuman yaku is only rewarded sanbaiman.

Thirdly, determine how much players have to pay:
• For wins on a self-draw, the base value is paid by all three opponents.
For East, however, the value is doubled one more time. East receives double payment, but also pays twice the amount of the base value when an opponent wins by self-draw.
• For wins on a discard, the discarding player must pay for all opponents, including East, i.e. four times the base value if the winner is not East, and three times the doubled base value if the winner is East.

Payments are rounded up to the next hundred.

To the hand value are added 100 points for each continuance counter for wins on a self-draw, and 300 points for wins on a discard.
In addition, the riichi bets on the table are collected by the winner.

If a player's score goes below zero, the game continues. The player will have a negative score and plays normally (he can declare riichi, he can pay the other players, ...).

When a player has two visible pungs and/or kongs of dragons and another player feeds him a third melded pung / kong of dragons, the feeding player is liable if the player wins with the Big Three Dragons yakuman.

When a player has three visible pungs and/or kongs of winds and another player feeds him a fourth melded pung / kong of winds, the feeding player is liable if the player wins with the Big Four Winds yakuman.

A pung / kong is visible if it is melded or if it is a concealed kong.

If the player wins by self-draw, the liable player must pay the full value of the hand, including all continuance counters points.
If the player wins by claiming a tile, the liable player shares the payment equally with the discarder of the winning tile. Only the discarder pays the continuance counters' points.
The feeding player is still liable even if the hand also qualifies for another yakuman.

There is no liability for feeding a Four Kongs or an After a Kong yaku.

	Fu
Winning	20
Seven pairs	25	No other minipoints are added.
Winning on a discard on a concealed hand	10
Winning by self-draw	2	Not counted in case of pinfu yaku.
Edge wait	2	Winning on the 3 or 7 tile of an 1-2-3 or 7-8-9 chow.
Closed wait	2	Winning on the central tile of a chow.
Pair wait	2	Winning on a tile completing a pair.
Open pinfu	2	Awarded when an open hand is worth no minipoints beside the 20 minipoints for winning.

	Middle tiles	Terminals and honours	Valuable honour	Double wind
Chow	0	0	-	-
Melded pung	2	4	4	4
Concealed pung	4	8	8	8
Melded kong	8	16	16	16
Concealed kong	16	32	32	32
Pair	0	0	2	4

If the winning tile finishes a pung, it counts as a concealed pung in case of self-draw, and it counts as a melded pung in case of winning on a discard.

The two minipoints for edge, closed or pair wait can be claimed even if the hand is waiting for other tiles. Edge wait is 1-2 waiting for 3 or 8-9 waiting for 7. Closed wait is waiting for the central tile of a chow. Pair wait is waiting to finish the pair.
In special cases like  , even though it is only possible to win on , no minipoints can be claimed since the tile finishes neither an edge wait, a closed wait nor a pair wait.

The winning player gets one han for each dora in his hand.
If several dora indicators point to the same tile, the dora is counted for each indicator.
For example, if the initial dora indicator is , and a kan dora indicator is also , and the winning player have a pung in his hand, then he has 6 dora, giving 6 han.

Active dora come from:
• The initial dora indicator.
• Kan dora indicators: i.e. dora indicators revealed for each kong, whether the kong were made by the winning player or by another player.
• Ura dora indicators: i.e. dora indicators beneath other active dora indicators; only if the winning player has declared riichi.

When a kong is declared, the kan dora indicator must be revealed before the player discards.
• If a player wins by robbing a kong, there is no kan dora indicator for the robbed kong. Indeed, the robbed kong was not completed. If the dora indicator was already revealed before the win is declared, the indicator is turned back face down.
• If a player wins on the replacement tile after a kong, the kan dora indicator is revealed.