Japanese Mahjong yaku

In Japanese mahjong, yaku (Japanese: 役) is a specific combination of tiles that increases the value of the player's hand. In the Japanese version of the game, a player must have a minimum of one yaku in their hand in order to legally win. Each yaku has a specific han value: for each han a hand contains, the hand's point value increases exponentially.

(Note: this article uses only English and Japanese terms whenever possible. Terms like "chow," "pung," and "kong" are not used here, since Japanese players use different terms while playing mahjong.)

Overview

Yaku are somewhat similar to poker hands. They fit certain patterns based on the numbers or types of tiles included, as well as the relative value of those tiles. Furthermore, each yaku has a han value based on the probability of attaining the yaku. The more difficult the yaku is to achieve, the more it is worth.

Unlike poker, however, a hand can have more than one yaku, and their han values can be combined. In fact, it is a vital strategy in mahjong to try and aim for hands that have several yaku together in order to increase the player’s score.

There are three basic classes of yaku: menzen (closed hand only), kuisagari (literally: eat and decrease, where the han value decreases by one if the hand is open), and yaku where the han value is the same regardless of whether the hand is closed or open.

Most people new to Japanese mahjong—or mahjong in general—balk at the complexity of rules for valid hands. At first, there does not seem to be any underlying logic to them; they look like random collections of tile combinations that seem difficult to get. However, there is in fact an underlying logic to them, and in essence it is quite simple.

The basic concept of a yaku is that it fits one of three basic criteria:
* It contains a pattern of some kind
* It has a great deal of consistency, or
* It involves a great deal of luckThe rule of thumb: a yaku has a pattern, and the more difficult the pattern is to achieve, the more it is worth.

Different categories of yaku

All yaku can be divided into five basic categories, depending on the dominant feature. The features are: patterns based on sequences, patterns based on triplets and/or quads, consistency of the type and numbers of the tiles, lucky draws from the wall, and special criteria.

Basic terms

Here are a few important terms related to mahjong hands.

Open hand: a hand where the player has used another player's discarded tile to complete a sequence, triplet, or quad. It is called open because players who "call" on a discard must place the set of tiles face-up on the table for all to see.

Closed hand: a hand composed exclusively of tiles drawn from the wall.

Sequence: three numbered tiles of the same suit in sequential order. (Called "chow" in Chinese)

Triplet: three tiles of the same number in the same suit, or three identical honor tiles.

Quad: four tiles of the same number in the same suit, or four identical honor tiles.

Pair: two identical tiles.

List of yaku

The following is a list of all the yaku, their names in Japanese, as well as their han values and any special conditions related to them. They are listed here in groups according to the underlying patterns that define the yaku.

Special criteria

Ready hand

(Japanese: "rīchi" - 立直, リーチ): 1 han, closed hands only

If a player’s hand needs only one tile to win and the player has not claimed any tiles from other players to form groups, then they may declare ready. To do so, the player calls out “rīchi”, places a 1000-point stick on the table as a deposit, and discards their tile sideways.

From this point on, the player may not change the content of their hand. They must discard any tile that does not allow them to win. One exception: if the player has a triplet and they draw the fourth tile to complete a quad, they may declare a quad as long as it does not change the content of their hand.

For example, if a player has three 3 of dots and they are using it as a triplet, then they may make it into a quad if they draw the fourth 3. On the other hand, if two of the 3’s are being used as a pair and the third 3 is part of a sequence, declaring a quad would change the composition of the hand, and therefore would not be allowed.

Declaring ready is often used by players who wish to increase the value of their hand, as well as to make an otherwise invalid hand (i.e. a hand containing no yaku) into a valid one.

However, there are certain risks involved. First, if a player declares ready, the other players know that they are ready to go out, and thus tend to be more careful about what tiles to discard. Secondly, the hand is “locked in” once declared ready, and the players cannot change the composition to increase its value. Third, since the player must discard all non-winning tiles, it does not allow the player to keep tiles that other players may need to win, thus increasing the likelihood of “dealing in” to other players’ hands. Finally, if one player declares ready and another player wins, the player who declared ready must forfeit their 1000-point deposit to the winner.

Double-ready

(Japanese: "daburu rīchi" – ダブルリーチ, or "daburī" - ダブリー): 2 han, closed hands only

If a player can declare ready within the first round of a hand, they can call "daburu rīchi" to declare a double-ready for two han instead of one. All other conditions are the same as declaring a normal ready.

Seven pairs

(Japanese: "chītoitsu" – 七対子, or "chītoi" - 七対): 2 han, closed hands only

A hand composed of seven pairs is considered a valid hand in Japanese mahjong. It is one of only two hands that are an exception to the rule require winning hands to have four groups and one pair. It also has its own special rules for scoring.

Most Japanese play with the rule that all seven pairs must be unique. In other words, if a hand contains four red dragons and five other independent pairs, the four red dragons may not be split into two pairs to make a seven pairs hand.

Yaku based on patterns in sequences

No-points hand

(Japanese: "pinfu" – 平和): 1 han, closed hands only

This is a very common yaku, since it is rather easy to get. A no-points hand is just that—a hand that is worth no additional "fu"-points whatsoever. Specifically, the hand must have no triplets or quads, and must not contain any bonus tiles (i.e., dragons, player’s own wind, or wind of the round) for the pair.

Furthermore, the hand must be waiting for multiple tiles to go out. The reason for this is that, if the hand is in a closed, edge, or pair wait, it is worth points, thus violating the no-points condition.

Two identical sequences

(Japanese: "īpeikō" – 一盃口): 1 han, closed hands only

Two sequences of the same numbered tiles in the same suit.

Three colour straight

(Japanese: "sanshoku doujun" – 三色同順, or "sanshoku" - 三色): 2 han for closed hands, 1 han for open hands

Three sequences of the same numbers in all three suits.

Straight through

(Japanese: "ikkitsūkan" – 一気通貫, or "ittsū" - 一通): 2 han for closed hands, 1 han for open hands

Three sequences of the same suit numbered 1-2-3, 4-5-6, and 7-8-9. In other words, a single-suit straight from 1 to 9.

Two sets of identical sequences

(Japanese: "ryanpeikō" – 二盃口): 3 han, closed hands only

One pair of identical sequences in the same suit, and a second pair of matching sequences that do not match the first.

Yaku based on patterns in triplets and/or quads

There are only four yaku in this group. Any time it involves a triplet, a quad is also acceptable, though if it specifically involves quads, triplets do not count. Each yaku is worth two han, regardless of whether the hand is closed or open.

All triplet hand

(Japanese: "toitoihō" – 対々和, or "toitoi" - 対々): 2 han

The hand consists of all triplets or quads; no sequences.

Three concealed triplets

(Japanese: "san ankō" – 三暗刻): 2 han

Three sets of triplets or quads formed without calling on any other tiles. The fourth set can be an open triplet or quad, or a sequence.

Three colour triplets

(Japanese: "sanshoku doukō" – 三色同刻): 2 han

Three triplets consisting of the same numbers in all three suits.

Three quads

(Japanese: "san kantsu" – 三槓子): 2 han

Three quads in one hand. Can be open or closed.

Yaku based on the types of tiles in the hand

These yaku all have some type of pattern regarding either the suits or the numbers of the tiles. Except for the one-han combinations or the ones specifically involving dragons or special winds, they all lose one han if the hand is open.

All simples

(Japanese: "tanyaochū" – 断么九, or "tanyao" - 断么): 1 han

Every tile in the hand is a number tile between 2 and 8.

("Tanyaochū": literally "no 1's or 9's")

Special tiles

(Japanese: "yakuhai" – 役牌, or "huanpai" - 飜牌): 1 han per triplet or quad

Any triplet or quad that includes either a dragon, the player’s own wind, or the wind of the round. Note that in Japanese mahjong, there are only two winds per session: east and south, so west and north can not be winds of the round. If a wind is both the player’s own wind and the wind of the round, it is worth two han per group.

Terminal or honor in each set

(Japanese: "chantaiyao" – 全帯么, or "chanta" - チャンタ): 2 han for closed hands, 1 han for open hands

All triplets and pairs in the hand must be either 1’s or 9’s (terminals), or honor tiles (i.e., winds or dragons). For sequences, they must be either 1-2-3, or 7-8-9.

One suit plus honors

(Japanese: "hon'īsō" – 混一色, or "hon'itsu" - 混一): 3 han for closed hands, 2 han for open hands

The hand contains tiles from only a single suit, plus dragon or wind tiles.

Terminal in each set

(Japanese: "jun chantaiyao" – 純全帯么, or "junchan" - 純チャン): 3 han for closed hands, 2 han for open hands

The "jun" in "junchan" literally means "pure." As such, it's a pure terminal-based hand. All triplets and pairs in the hand must be either 1’s or 9’s (terminals). Sequences must be either 1-2-3 or 7-8-9.

All terminals and honors

(Japanese: "honrōtō toitoihō" [all triplets] – 混老頭対々和, or "honrō toitoi" - 混老 対々 / "honrōtō chītoitsu" [seven pairs] – 混老頭七対子, or "honrō chītoi" - 混老 七対): 4 han

There are only two possibilities for a hand that are all terminals and honors: either all triplets and quads, or seven pairs. For the all triplets variant, you may not add the all triplets yaku to this as it is already included in the han value. The same applies for seven pairs: it is only worth four han.

Little three dragons

(Japanese: "shōsangen" – 小三元): 4 han

Triplets or quads of two dragons, plus a pair of the third. You can't add two "special-tiles" yaku to this, as they are already included in this 4-han value.

Single suit hand

(Japanese: "chin'īsō" – 清一色, or "chin'itsu" - 清一): 6 han for closed hands, 5 han for open hands

All tiles in the hand are exclusively of one suit with no honor tiles.

Yaku based on luck

These yaku all relate to draws from the wall under special, lucky circumstances. They are all worth 1 han.

Self pick

(Japanese: "menzenchin tsumohō" – 門前清自摸和, or shortly "tsumo" - 自摸, ツモ): 1 han

If a player has a concealed hand and then draws the last tile from the wall to complete it, it adds one han to its value.

One-shot

(Japanese: "ippatsu" – 一発): 1 han, for hands declared ready only

If a player declares ready (calls rīchi) and then receives the winning tile within one round of play, it adds one han to the hand’s value. The tile can either be a discard from another player or drawn from the wall. One-shot no longer applies when any other player makes a meld.

Last tile from the wall

(Japanese: "haitei raoyue" – 海底撈月, or "haitei" - 海底): 1 han

If the last available tile from the wall (i.e., the last tile the players can draw before reaching the dead wall) completes a hand, the hand’s value increases by one han. This applies to either the person drawing the tile ("haitei tsumo"), or to a person claiming the tile after it is discarded ("hōtei raoyui" - 河底撈魚, or "hōtei" - 河底).

("Haitei raoyue": "to dip up the moon from the ocean bed", and "hōtei raoyui": "to dip up a fish from the riverbed")

Going out on a supplemental tile from the dead wall

(Japanese: "rinshan kaihō" – 嶺上開花, or "rinshan" - 嶺上): 1 han

When a player declares a quad, they must draw a supplemental tile from the dead wall to keep the number of tiles in the hand consistent. If that tile completes the hand, it adds one han to the hand’s value.

("Rinshan kaihō": "a flower blooms on a ridge")

One special point about this rule: if the player uses a discard to complete a quad, then completes their hand with a tile from the dead wall, the player who discarded the tile is responsible for paying the entire amount for the hand.

Robbing a quad to go out

(Japanese: "chankan" – 槍槓): 1 han

If a player has an open triplet and draws the fourth tile in the set to make a quad, they can add it to the triplet. However, if another player requires that tile to complete their hand, they can rob that tile from them. Doing so increases the hand’s value by 1 han.

For example, if player A has three 6’s of dots in an open triplet, and they draw the fourth 6, they can add it to the triplet for a quad. If player B has a 4-5 of dots sequence in their hand, and that is the only set left to complete in their hand, they can then rob that fourth 6 to win. Player A then has to pay the full value of player B’s hand.

Yakuman hands

In mahjong, there are a number of special hands that are so difficult to get that they are worth the limit in points just for having them. Just like the yaku, they all fit one of four criteria: patterns in sequences, patterns in triplets, consistency of tiles, or luck.

Some of these combinations may have different names in different countries. The names used here mostly come from American publications, which are based on Chinese translations.

Thirteen orphans

(Japanese: "kokushi musō" – 国士無双)

Along with seven pairs, this is the only hand that contradicts the requirement for a hand to have four sets and a pair. In a thirteen orphans hand, the player has one of each dragon tiles, one of each wind tiles, a 1 and a 9 (terminal) from each suit, plus any tile that matches anything else in the hand.

("Kokushi musō": "a peerless distinguished figure")

Nine gates

(Japanese: "chūren pōtō" – 九蓮宝燈): closed hands only

A hand composed of 1-1-1-2-3-4-5-6-7-8-9-9-9 of one suit, plus any other tile of the same suit.

Regardless of the value of the extra tile, this is always a standard mahjong hand of four sets and a pair, as shown in the animation.

Four concealed triplets

(Japanese: "sū ankō" - 四暗刻)

The hand has only triplets or quads, none of which are made from tiles taken from other players’ discards. If the hand has two pairs left when the hand is ready, then it can only qualify as a yakuman hand if the tile is drawn off the wall. In other words, the only way to win by using a discarded tile is if all four triplets (or quads) have already been completed and the player waits to complete the pair.

Big three dragons

(Japanese: "daisangen" – 大三元)

A triplet or quad of each type of dragon tile.

Little four winds and big four winds

(Japanese: "shōsūshī / daisūshī" – 小四喜 / 大四喜)

A hand consisting of all four wind tiles. Little four winds has three wind triplets or quads plus a pair of winds, while big four winds has triplets or quads of all four winds.

Four quads

(Japanese: "sū kantsu" – 四槓子)

Four quads in one hand. Can be open or closed. Note that in some rules, a round is a draw when four quads are made by two or more players, or when the fifth quad is made.

All green

(Japanese: "ryūīsō" – 緑一色)

A rather unusual hand. This hand contains only green dragons, plus the 2, 3, 4, 6, or 8 of bamboo. The reason for the limit of bamboo tiles is that the other tiles (1, 5, 7, and 9) have red paint on them, thereby not making them “all green.” Although this yakuman hand can include green dragons, it does not have to.

All honors

(Japanese: "tsūīsō" – 字一色)

A hand composed exclusively of wind and dragon tiles.

All terminals

(Japanese: "chinrōtō" – 清老頭)

A hand consisting solely of triplets or quads of 1’s and 9’s (terminals).

Heavenly hand

(Japanese: "tenhō" – 天和): Dealer only

If the 14 tiles that the dealer draws compose a complete hand, it automatically becomes a yakuman regardless of its contents. Note that, since the fourteenth tile is considered a drawn tile, coupled with the fact that it is a closed hand, the “minimum yaku requirement” is satisfied with the “self-pick” yaku.

Earthly hand

(Japanese: "chīhō" – 地和): Non-dealer only

If a non-dealer is dealt 13 tiles that are one tile away from a completed hand, and then draws the fourteenth tile from the wall to complete it on the first draw, it automatically becomes a yakuman hand, regardless of its contents. Again, because it’s a “self-pick” from a closed hand, it technically satisfies the “one yaku minimum” requirement.

See also

*Mahjong
*Japanese Mahjong scoring rules