Japanese Mahjong scoring rules

Japanese Mahjong scoring rules are used for Japanese Mahjong, a game for four players common in Japan. The rules were organized in the Taishō to Showa period as the game became popular.

The scoring system uses structural criteria as well as bonuses. Players start with 20,000 to 30,000 points. Scores are counted using sticks of 10,000 points, 5,000 points, 1,000 points and 100 points. A game often ends when all the points of a player are lost, which is a situation called hakoten,dobon,buttobi, etc.

There are two criteria in determining the winning points: han and fu, which correspond to a points table. Han is the unit for the value of yaku, which are particular patterns or conditions of a hand. Fu is the value of melds, waits and "going out".

The payment to the winner of a hand is calculated as follows:

In the case of a draw, points are transferred according to the nō-ten bappu rule. In the event of a penalty, such as claiming a win with an illegal hand, then points are transferred via the chombo rule.

The total number of han (飜) of all the kinds of yaku (役; winning hand) in the hand is summed up. Each dora (ドラ) increases the han value of a hand. Dora are not regarded as yaku, and no hand can be won without a yaku even if there are some dora tiles.

If there is more than one way to arrange the winning hand, the arrangement with the highest han is used. For example, a hand could be either ryanpeikou (二盃口) or chītoitsu (七対子), but since ryanpeikou is three han where chītoitsu is two han, ryanpeikou should prevail. Some yaku have their han value reduced by one if the hand is not closed.

If a hand has five han or more, it is always counted by mangan (満貫) as a unit and it is not necessary to calculate fu (符) or basic points.

Fu (符) is counted in the order below and then rounded up to the tens. There may be variations of rules for counting it.

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