Yaku (役) — Complete Reference
10.1 What Are Yaku?
A yaku (役) is a scoring pattern or condition that validates a winning hand. In riichi mahjong, a hand must have at least one yaku to be declared as a win. Having a complete tile pattern (4 mentsu + 1 pair) is not sufficient—without yaku, the hand is "yakuman-nashi" (no yaku) and cannot be declared. This yaku requirement is the central feature that distinguishes riichi mahjong from simpler mahjong variants and creates the game's strategic depth: you must not only build a complete hand, but build one that satisfies specific conditions.
Each yaku is worth a specific number of han (飜), which is the primary unit for determining hand value. Some yaku have different han values when the hand is open vs. closed. Some yaku are only valid when closed. The total han count of all applicable yaku, combined with dora, determines the hand's scoring tier.
10.2 Standard Yaku — 1 Han
Riichi (立直) — 1 han, closed only
Declared when a closed hand reaches tenpai. The player places a 1,000-point deposit and cannot change their hand. Enables ippatsu and ura dora. This is the most common yaku in the game. See Module 14 for full details.
Menzen Tsumo (門前清自摸和) — 1 han, closed only
Winning by self-draw (tsumo) with a closed hand. Any closed hand that wins by tsumo has this yaku automatically. Often paired with riichi for a quick 2-han win.
Tanyao (断幺九) — 1 han
All tiles in the hand are simples (2-8 of any suit). No terminals (1, 9) or honors. Under "kuitan ari" rules (most common), tanyao is valid even with an open hand. Under "kuitan nashi" rules, tanyao requires a closed hand.
Kuitan (喰い断): Whether open tanyao is allowed is one of the most common ruleset variations. Most online platforms (Tenhou, Mahjong Soul) default to kuitan ari (open tanyao allowed). Some tournament rulesets, particularly older Japanese professional league rules, use kuitan nashi. Always check.
Pinfu (平和) — 1 han, closed only
A hand composed entirely of sequences (no triplets), with a ryanmen (two-sided) wait, and a pair that is not a yakuhai tile (not round wind, not seat wind, not dragon). Pinfu essentially means "no fu from the hand structure." This is one of the most common and most efficient yaku because the hand structure requirement (all sequences, ryanmen wait) aligns perfectly with tile-efficient play.
Iipeiko (一盃口) — 1 han, closed only
Two identical sequences in the same suit (e.g., two copies of 2m-3m-4m). Must be concealed. Becomes ryanpeiko (二盃口, 3 han) if the hand has two sets of identical sequences.
Yakuhai (役牌) — 1 han per set
A triplet (or kan) of: any dragon tile (haku/hatsu/chun), the current round wind, or your current seat wind. Each qualifying set is 1 han. A double-wind set (tile matches both round and seat wind) counts as 2 han. Yakuhai is valid open or closed, making it the easiest yaku to achieve in an open hand.
Haitei / Houtei — 1 han each
Haitei raoyue (海底摸月): winning by tsumo on the very last drawable tile. Houtei raoyui (河底撈魚): winning by ron on the very last discard. These are situational and cannot be planned for reliably.
Rinshan Kaihou (嶺上開花) — 1 han
Winning on the replacement tile drawn after declaring a kan. See Module 26.
Chankan (搶槓) — 1 han
Winning by claiming a tile that another player uses for an added kan (shouminkan). Rare but notable.
Ippatsu (一発) — 1 han, closed only
Winning within the first go-around after declaring riichi, before any calls interrupt the sequence. Adds 1 han to the riichi hand. Cannot be aimed for deliberately—it is a bonus.
10.3 Standard Yaku — 2 Han
Double Riichi (ダブル立直) — 2 han, closed only
Declaring riichi on your very first discard, before any calls have been made in the hand. Rare but powerful. Replaces normal riichi (not cumulative—it is 2 han total, not 2+1).
Chanta (混全帯幺九) — 2 han (1 han open)
Every group and the pair contains at least one terminal or honor tile. Must have at least one sequence (otherwise it becomes honroutou). Requires a mix of suited terminals and honor tiles across all groups.
Ittsu / Ikkitsukan (一気通貫) — 2 han (1 han open)
A straight of 1-2-3, 4-5-6, 7-8-9 in the same suit. Three specific sequences forming a full 1-9 run.
San Shoku Doujun (三色同順) — 2 han (1 han open)
The same sequence in all three suits (e.g., 4-5-6 in manzu, pinzu, and souzu). A popular and satisfying yaku that requires coordinating across suits.
San Shoku Doukou (三色同刻) — 2 han
The same triplet number in all three suits (e.g., 444m, 444p, 444s). Rare because it requires three specific triplets.
Toitoi (対々和) — 2 han
All four groups are triplets (or kans). No sequences. Usually achieved with an open hand through multiple pon calls. Common in honor-heavy hands.
San Ankou (三暗刻) — 2 han
Three concealed triplets. The fourth group may be open or a sequence. Note: if the winning tile completes the third triplet by ron, that triplet is considered open (minkou), which disqualifies it. This edge case is a common source of mistakes.
Shou San Gen (小三元) — 2 han (+ yakuhai)
Two dragon triplets and a dragon pair. Since the two dragon triplets each provide yakuhai (1 han each), the total is effectively 4 han minimum (2 for shou san gen + 1 + 1 for the two yakuhai). A strong hand.
Honroutou (混老頭) — 2 han (+ toitoi)
Hand contains only terminals and honors. Since no sequences are possible with only terminals and honors, this always combines with toitoi (or chiitoitsu), making it effectively 4+ han.
Chiitoitsu (七対子) — 2 han, closed only, fixed 25 fu
Seven distinct pairs. Special hand structure (not 4+1). Always 25 fu regardless of composition.
10.4 Standard Yaku — 3+ Han
Honitsu (混一色) — 3 han (2 han open)
Hand uses only one suit plus honor tiles. A common "plan B" hand when your starting tiles cluster in one suit with some honors. The open version (2 han) is frequently used with yakuhai calls for quick hands.
Junchan (純全帯幺九) — 3 han (2 han open)
Like chanta, but with no honor tiles—every group and the pair must contain a terminal, but all tiles are suited. More restrictive and therefore higher value than chanta.
Ryanpeiko (二盃口) — 3 han, closed only
Two sets of identical sequences. Effectively the closed-hand version of "all sequences come in pairs."
Chinitsu (清一色) — 6 han (5 han open)
Hand uses only one suit—no honors, no other suits. The highest-value non-yakuman yaku. A chinitsu hand is often visually obvious from the discards (heavy discards in the other two suits), making it easy for opponents to read.
10.5 Yakuman (役満) — Limit Hands
Yakuman are extremely rare, extremely valuable hands worth the maximum base score of 32,000 points (non-dealer) or 48,000 (dealer). Standard yakuman include:
| Yakuman | Japanese | Description |
|---|---|---|
| Kokushi Musou | 国士無双 | One each of all 13 yaochuuhai + one duplicate |
| Suu Ankou | 四暗刻 | Four concealed triplets |
| Dai San Gen | 大三元 | Triplets of all three dragons |
| Shousuushii | 小四喜 | Three wind triplets + wind pair |
| Daisuushii | 大四喜 | All four wind triplets (double yakuman in some rules) |
| Tsuuiisou | 字一色 | Hand of only honor tiles |
| Ryuuiisou | 緑一色 | All green tiles (2s,3s,4s,6s,8s,hatsu) |
| Chinroutou | 清老頭 | Only terminal tiles (1s and 9s) |
| Chuurenpoutou | 九蓮宝燈 | 1-1-1-2-3-4-5-6-7-8-9-9-9 + any in same suit |
| Suu Kantsu | 四槓子 | Four kans |
| Tenhou/Chiihou | 天和/地和 | Dealer wins on initial deal / non-dealer on first draw |
QUIZ — Question 10.1
You have an open hand with: pon of hatsu (6z), chi of 4p-5p-6p, chi of 7s-8s-9s, and in hand: 2m 3m 4m 1z 1z. If 1z is not your seat wind or round wind, does this hand have yaku?
Answer: A. Hatsu (green dragon, 6z) is always a yakuhai regardless of seat/round wind. A triplet of hatsu gives 1 han, satisfying the minimum yaku requirement. The hand is open, which is fine—yakuhai works open or closed. Option C is wrong because the hand contains 1z (honor tile), disqualifying tanyao. Option D is wrong because you only need 1 han minimum.
10.6 Yaku Frequency in Real Games
Not all yaku occur with equal frequency. Data from Tenhou ranked games shows the following approximate distribution of yaku in winning hands (these percentages reflect how often each yaku appears in hands that actually win, not how often players attempt them):
| Yaku | Approximate Frequency | Notes |
|---|---|---|
| Riichi | ~40-45% of winning hands | Most common yaku by far |
| Tanyao | ~20-25% | Extremely common, especially with kuitan ari |
| Pinfu | ~18-22% | Common in efficient closed hands |
| Yakuhai | ~25-30% | Often the basis for open hands |
| Menzen Tsumo | ~15-20% | Accompanies all closed tsumo wins |
| Ippatsu | ~7-10% | ~15-20% of riichi hands win with ippatsu |
| Honitsu | ~4-6% | Less common but high-value |
| Chiitoi | ~3-5% | Niche but important alternative structure |
| Toitoi | ~2-4% | Usually open, triplet-based |
| Chinitsu | ~1-2% | Rare but devastating when completed |
| Yakuman (any) | ~0.03-0.05% | Roughly 1 in 2,000-3,000 hands |
These frequencies, derived from large-sample Tenhou data analyses shared by the Japanese mahjong statistics community, reveal that the vast majority of winning hands use basic yaku: riichi, tanyao, pinfu, and yakuhai account for the overwhelming majority. Exotic yaku like san ankou, ittsu, or san shoku appear much less frequently. This data supports the practical advice found in Fukuchi Makoto's (福地誠) beginner texts: master the common yaku first, because they constitute 90%+ of actual wins.
10.7 Yaku Compatibility — Which Yaku Combine?
Understanding which yaku can combine is important for maximizing hand value. Some key compatibility notes:
Pinfu + Tanyao: A very common and efficient 2-han combination. Requires: all sequences, all simples (2-8), ryanmen wait, non-yakuhai pair, closed hand. Adding riichi makes it 3 han (pinfu + tanyao + riichi), which with 30 fu scores 4,000 non-dealer ron — a solid, frequently achievable hand. This combination is so common that the Japanese shorthand "メンタンピン" (men-tan-pin, for menzen tsumo + tanyao + pinfu) refers to the classic 3-yaku closed tsumo hand.
Yakuhai + Honitsu: A common open-hand combination yielding 3+ han (1 yakuhai + 2 honitsu open). With additional yakuhai or dora, this easily reaches mangan. This is the standard "value open hand" plan discussed in Hirasawa Genki's (平澤元気) instructional content.
Incompatible combinations: Pinfu and toitoi can never combine (pinfu requires all sequences, toitoi requires all triplets). Tanyao and chanta are mutually exclusive (tanyao excludes terminals/honors, chanta requires them). Chiitoi and any mentsu-based yaku are incompatible (different hand structures). Knowing these exclusions prevents wasted effort pursuing impossible combinations.
QUIZ — Question 10.2
What is the most common yaku in winning hands on Tenhou, appearing in approximately 40-45% of all wins?
Answer: A. Riichi appears in approximately 40-45% of all winning hands. This is because riichi is available to ANY closed tenpai hand regardless of composition, making it the most universally applicable yaku. Tanyao and yakuhai are each in the 20-30% range, and pinfu at approximately 18-22%. The dominance of riichi in the yaku distribution is one of the reasons the riichi declaration is considered the defining mechanic of Japanese mahjong.
Source notes: Yaku definitions and han values follow standard Japanese riichi mahjong as codified by major organizations. Minor variations exist for some optional yakuman (paarenchan, open riichi, etc.), which are not listed here as they are not part of standard rules. Han values for open vs. closed yaku are universally agreed upon in standard rulesets.