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. The combination of han and fu then corresponds to values indicated from the scoring table, and/or the two numbers of han and fu factor into an equation, by which the scoring table is derived.

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

Main article: List of yaku

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 provide one extra han each. In general, an increase of value by one han 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.

Fu

Fu 「符」 (pronounced as foo) takes the hand composition into consideration in terms of tile melds, wait patterns and/or win method. In addition, 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. One exception falls on the chii toitsu yaku, which is set to 25 fu by default.

Fu factors into the following elements:

Tile groups

For shuntsu (sequences), the fu count is 0. For koutsu (triplet) and kantsu (four-of-a-kind), the fu value depends on whether they are tanyaohai (simples) or jihai/routouhai (honor/terminals).

English	Romaji	Simples	Honor/Terminal
Open triplet	Minkou	2 fu	4 fu
Open kan	Minkan	8 fu	16 fu
Closed triplet	Ankou	4 fu	8 fu
Closed kan	Ankan	16 fu	32 fu

Waits

The different basic wait patterns count for fu as well. Other wait patterns not listed include nobetan and ryanmenten. Nobetan counts for a tanki; and ryanmenten counts for ryanmen. Other combination patterns factor fu the same as the basic patterns listed here. However, the fu counts only one time. For example, a combination of tanki and kanchan only generates 2 fu from one pattern but not for both.

As for shanpon, the fu generated with this pattern rests on the tile groupings themselves as indicated in the above table.

English	Romaji	Fu value
Open wait	Ryanmen	0 fu
Closed wait	Kanchan	2 fu
Edge wait	Penchan	2 fu
Pair wait	Tanki	2 fu

Winning condition

• Winning with a closed hand by ron, the hand is awarded 10 fu. These 10 fu are called menzen-kafu and do not count against the player for achieving pinfu.
• A win by tsumo with an open or closed hand is worth 2 fu.
• An exception to the fu for tsumo is a closed hand that satisfies all other criteria for pinfu. Such a hand does not score 2 fu for tsumo and instead gains the han for pinfu.
• An open hand won by ron without any fu from koutsu or the waiting pattern gains 2 fu. This makes all open hands ineligible for pinfu.

Scoring procedure

Calculating basic points

To determine the point value of a hand, the following procedure is used:

1. If the hand is a yakuman, then hand scores 8,000 basic points × number of yakuman.
2. Otherwise, determine the hand's valid yaku.
3. Count the han based on the yaku.
4. Count any number of dora to the han count.
5. 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.
6. If the han count is 4 or less, then count fu.
7. 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)}, using basic points = 2,000 if the former exceeds 2,000

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, rounded up to a full 100. The dealer in this case pays 2 × basic points, rounded up to a full 100.
• When a non-dealer wins by ron, the discarding player pays the winner 4 × basic points, rounded up.
• When the dealer goes out by tsumo, the dealer scores 2 × basic points from all players, rounded up.
• When the dealer goes out by ron, the dealer earns 6 × basic points from the responsible non-dealer, rounded up.

So finally, a hand's point value is finally expressed as:

Points = Basic points x Payment multiplier

Aotenjou

Main article: 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.

Honba

In the event of ryuukyoku or a dealer win, the honba or tsumibou count increases by 1 for the next hand. If someone wins a hand and East does not, the honba count resets back to zero.

This count increases hand values increases by a total of 300 per honba. For ron, the discarder pays the additional 300 points. For tsumo, everyone pays an additional 100 each. These extra points are added to the hand value after the capping as mangan, haneman, etc., so a non-dealer mangan tsumo with 2 honba costs 2,200 for a non-dealer and 4,200 for the dealer.

In the case of sekinin barai, the yakuman tsumo payment is borne entirely by the discarder of the ponned tile, who also has to pay 300 per honba. On a ron, the yakuman value is split between the discarder of the winning tile and the discarder of the earlier ponned tile. Most rules have the winning tile discarder pay for all honba.

End game score

Main article: Uma

At the end of the game, the raw points are used to calculate the end game score.

Scoring table

Main article: Score table memorization

The score table is generated using the Basic points and the Payment multipliers. Similar to a multiplication, the awarded points are arranged in accordance to Han and Fu values. With known Han and Fu values, the points can simply be read straight off the table.

Dealer

Han/Fu	20	25	30	40	50	60	70	80	90	100	110
1 han	-- --	-- --	500 1500	700 2000	800 2400	1000 2900	1200 3400	1300 3900	1500 4400	1600 4800	1800 5300
2 han	700 2000	-- 2400	1000 2900	1300 3900	1600 4800	2000 5800	2300 6800	2600 7700	2900 8700	3200 9600	3600 10600
3 han	1300 3900	1600 4800	2000 5800	2600 7700	3200 9600	3900 11600	4000 12000
4 han	2600 7700	3200 9600	3900 11600	4000 12000
Mangan (5 han)	4000 12000
Haneman (6,7 han)	6000 18000
Baiman (8,9,10 han)	8000 24000
Sanbaiman (11,12 han)	12000 36000
Yakuman (13+ han)	16000 48000

Nondealer

Han/Fu	20	25	30	40	50	60	70	80	90	100	110
1 han	-- --	-- --	300/500 1000	400/700 1300	400/800 1600	500/1000 2000	600/1200 2300	700/1300 2600	800/1500 2900	800/1600 3200	900/1800 3600
2 han	400/700 1300	-- 1600	500/1000 2000	700/1300 2600	800/1600 3200	1000/2000 3900	1200/2300 4500	1300/2600 5200	1500/2900 5800	1600/3200 6400	1800/3600 7100
3 han	700/1300 2600	800/1600 3200	1000/2000 3900	1300/2600 5200	1600/3200 6400	2000/3900 7700	2000/4000 8000
4 han	1300/2600 5200	1600/3200 6400	2000/3900 7700	2000/4000 8000
Mangan (5 han)	2000/4000 8000
Haneman (6,7 han)	3000/6000 12000
Baiman (8,9,10 han)	4000/8000 16000
Sanbaiman (11,12 han)	6000/12000 24000
Yakuman (13+ han)	8000/16000 32000

External links

Online hand scoring calculator