Japanese mahjong scoring rules
Japanese mahjong features a very complex scoring system. Every mahjong hand has a value in terms of han and fu associated with them. From a scoring table, the combination of han and fu then corresponds to values indicated These values are derived using han and fu into the points equation.
By default, most games start players at 25,000 points, with the goal of scoring at least 30,000 to declare victory for the points leader. Point settings may be flexible to vary both the starting score and the goal score.
Scoring factors
Han
Han 「飜」 is the main portion of scoring, as each yaku is assigned a han number. Some may factor being open or closed; for others, this would not matter. Any dora in the winning hand provides one extra han each. In general, an increase of value by one han roughly doubles the number of points, until the cap of mangan.
Yakuman do not have a han value. If a winning hand satisfies at least one yakuman, han and fu are not counted for the hand. Points are awarded based on the yakuman value; and if multiple yakuman are allowed, then the yakuman values are multipled by the number of yakuman patterns in the hand. Finally, any hand that accumulates 13 or more han is counted for a kazoe yakuman.
Fu
Fu 「符」 (pronounced as foo) takes the hand composition into consideration in terms of tile melds, wait patterns and/or win method. Every hand begins with a default start value of 20 fu. To determine the final number of fu, the sources of fu are added up along with the base number and then rounded up to the nearest 10. Even a fu count of 32 gets rounded up to 40. One exception falls on the chii toitsu yaku, which is fixed to 25 fu by default. While fu may be counted for hands worth 5 han or greater, it may no longer be necessary to count fu for human memorization. Hands of this value become solely dependent on the han count, regardless of the fu count. All-in-all, counting fu is most relevant for hands worth 4 han or less.
Scoring procedure
Calculating basic points
To determine the point value of a hand, the following procedure is used:
- If the hand is a yakuman, then hand scores 8,000 basic points × number of yakuman.
- Otherwise, determine the hand's valid yaku.
- Count the han based on the yaku.
- Count any number of dora to the han count.
- If the han count is 5 or more, then counting fu is no longer necessary. Score the hand according to its han value on the scoring table.
- If the han count is 4 or less, then count fu.
- After determining the number of han and/or fu, refer to the scoring table.
For any who prefer to use the equation, basic points for 5 han or less are computed as:
Basic points = fu × 2(2 + han); limit of basic points = 2,000, for mangan and beyond.
Payment multipliers
After determining the basic points, multiply based on the status as dealer and no-dealer as well as the win by ron or tsumo.
- When a non-dealer wins by tsumo, the player earns 1 × basic points from the other non-dealers. The dealer in this case pays 2 × basic points.
- When a non-dealer wins by ron, the discarding player pays the winner 4 × basic points.
- When the dealer goes out by tsumo, the dealer scores 2 × basic points from all players.
- When the dealer goes out by ron, the dealer earns 6 × basic points from the responsible non-dealer.
Finally with the multipliers applied, a hand's point value is finally expressed as:
Points = Basic points x Payment multiplier; points rounded up to the nearest 100.
Scoring table
The points derived from the equation and the payment multipliers are arranged in a scoring table. Players have the option of knowing the point scores by either deriving from the equation or brute force memorization.
Honba
Honba is an added counter to the number of consecutive hands, that did not produce a winning hand and/or the dealer position repeats. For each honba count, every hand is worth a total of 300 extra points. Once a winning hand does occur, the honba count resets back down to zero. The event of chombo may or may not produce a increase in the honba count; the common practice does not.
Summary
- Determine Han
- Determine Fu
- Refer to the scoring table, or memorize the corresponding point values
- Factor in honba and riichi bets
End game score
At the end of the game, the raw points are used to calculate the end game score. These are the two or three digit +/- numbers used to reflect a player's score. Instead of 30,000 points, a player's score may actually be displayed as +40.0.
Aotenjou
Aotenjou 「青天井」 is the practice of scoring hands without any limit imposed. This practice is rarely used, because without scoring limits, hands can produce ridiculously high point values. Naturally, that is induced by the exponential function of the basic points equation.
External links
- Japanese mahjong scoring rules in Japanese Wikipedia