Yaku variations
Different yaku may be subject to rule variations, such as altering the value or conditions of the yaku. A number of yaku are not included by default.
Chiitoitsu
Under most rulesets, chiitoitsu requires 7 unique pairs.
Some house rules may allow duplicate pairs (meaning 4-of-a-kind counts as 2 pairs), but this is not seen in standard play.
Double riichi
Score riichi as 2 han yaku instead of 1 han if called within the first uninterrupted go-around of a hand.
- Ari – Score double riichi as 2 han instead of 1 han.
- Nashi – Always score 1 han per riichi declaration.
Double yakuman
Score each of the listed patterns as a double yakuman.
- Nashi – All individual yakuman count as single yakuman.
- D – Daisuushii: Daisuushii counts as a double yakuman on its own.
- S – Suuankou tanki: Suuankou on a tanki wait counts as a double yakuman.
- K – Kokushi musou juusanmen machi : Kokushi with the thirteen-sided wait on the pair counts as a double yakuman.
- 9 – Junsei chuuren poutou: Chuuren with the nine-sided wait (tenpai with 1112345678999) counts as a double yakuman.
Haitei and houtei
- Ari – Both yaku are allowed.
- Nashi – Neither yaku is allowed.
Haitei and rinshan
Haitei normally requires a draw from the live wall, while kan draws from the dead wall. This rule, if ari, negates hatei's live wall requirement, allowing haitei and rinshan to score together.
- Ari – Allow this combination. Used in the 2012 EMA MCR.
- Nashi – Do not allow this combination. This is Japanese default.
Honitsu and Chinitsu
Score 1 more han for closed honitsu or chinitsu than open.
- Ari – Closed honitsu is scored 3 han and closed chinitsu is scored 6 han.
- Nashi – Honitsu is always scored 2 han and chinitsu is always scored 5 han, regardless of the hand state.
Ippatsu
Score an additional han for winning a riichi declaration within the next go-around.
- Ari – Score ippatsu as a 1-han yaku.
- Nashi – Don't score ippatsu.
Kazoe yakuman
Score a hand with 13 han or more as a yakuman.
- Ari – Score as a yakuman with 8,000 basic points.
- Nashi – Score as a sanbaiman with 6,000 basic points.
Kokushi and chankan
Allow a hand in tenpai for kokushi to ron an ankan through chankan.
- Ari – Allowed
- Nashi – Disallowed
Multiple yakuman
Allow yakuman to be combined.
- Ari – Yakuman can be combined.
- Nashi – Yakuman cannot be combined; score only one type of yakuman per hand.
Optional yaku
Many yaku are not included in the list of yaku, as they are not accepted as "standard yaku". House rules may include any amount of desired yaku. The following are particularly common examples; the optional yaku page contains more detailed rules and many more yaku.
Daisharin
Daisharin is an optional yaku, formed with a hand consisting of 22334455667788, all of the same suit. If disabled, such a hand would be worth at least 10 han.
Agari:
- Ari – Score this hand as a yakuman.
- Nashi – Score this hand normally.
For souzu and manzu, the hands are labeled as daichikurin and daisuurin, respectively.
Open riichi
Allow players to declare open riichi instead of a normal riichi. Open riichi is worth 2 han instead of the normal 1 han. The declarer must reveal the hand's waits, or the entire hand, at the same time as the declaration.
- Ari – Allow open riichi along with normal riichi.
- Wait shape – The declarer only needs to reveal 1, 4, 7, or 10 tiles if these completely describe the wait shape of the hand. The pair or pair wait must always be revealed.
- Nashi – Don't allow open riichi.
In a few rulesets, intentionally dealing into an open riichi will raise the hand up to a yakuman (penalizing the discarder).
Paarenchan
Score the eighth consecutive win of the same dealer as a yakuman.
- Ari - Yakuman scored.
- Nashi - Eighth hand scored normally.
Renhou
This is a yaku for winning on a discard before the winner's first turn in an uninterrupted go-around.
- YMan – Yakuman: Score this as a yakuman. No other yaku is necessary.
- M – Mangan: Score this as a mangan. No other yaku is necessary. If a regular count of the hand would give haneman or better, the normal scoring is used.
- Yaku – Renhou functions as a regular yaku, with an assigned han value. As a regular yaku, it is capable of combining with other yaku.
- Nashi – Renhou is not a yaku. The hand is scored normally, there must be at least one other yaku present for a valid win.
Pao
Pao is a penalty applied to players who allow others to guarantee certain types of yaku/yakuman.
Daisangen and daisuushii
Impose a liability payment on the player who has dealt the third pon/kanned dragon tile, or the fourth pon/kanned wind tile, if the caller wins with daisangen (big three dragons) or daisuushii (big four winds) later.
- Ari – Liable player pays full on tsumo, half on ron.
- Nashi – No liability for daisangen or daisuushii.
Suukantsu
Impose a liability payment on the player who has dealt the fourth kanned tile, if the caller wins with suukantsu (four kantsu) later.
- Ari – Liable player pays full on tsumo, half on ron.
- Nashi – No liability for suukantsu.
Daiminkan rinshan
Require that a player pay for a hand, as for a ron, when his or her discard is called for daiminkan and the caller wins a tsumo for rinshan kaihou on the replacement tile.
- Ari – Player dealing into daiminkan (or another kan called in the same turn) pays for the whole hand.
- Nashi – All players pay for the hand, as normal for a tsumo.
Pinfu tsumo
Allow pinfu to waive the 2 fu from tsumo, so that pinfu and menzen tsumo can be scored together.
- Ari - Pinfu and menzen tsumo can be scored together, for a base of 2 han 20 fu.
- Nashi - Pinfu cannot be scored if the hand wins by tsumo. An otherwise pinfu hand won with tsumo scores 1 han 30 fu.
Nagashi mangan
Score a mangan upon exhaustive draw for having discarding only yaochuuhai during the entire hand, with none of the yaochuuhai having been called by other players, and without having called any tiles oneself. If this is allowed, there are additional rules decisions necessary: Does it count as a win, or merely as replacement of the noten penalty? Are concealed kantsu allowed?
- Ari – Score nagashi mangan, but I don't know the details.
- Ari B – Score nagashi mangan as a replacement of the noten penalty, not as a fully-fledged win. I don't know what happens if you declare ankan, that will likely prevent nagashi mangan.
- Ari KW – Score nagashi mangan as a win (W), voiding noten riichi chombos and collecting riichi bets and honba payments. It is legal to declare a concealed kantsu (K) and still score nagashi mangan.
- Nashi – Don't allow nagashi mangan.
Rinshan fu
Award a hand winning with the rinshanpai (kan replacement tile) the usual 2 fu for winning with a self-drawn tile.
- 2 fu – Award the hand 2 fu for tsumo.
- Nashi – Don't count any fu for tsumo on the rinshanpai.
Ryanpeikou
Score 3 han for completing two iipeikou in a hand.
- Ari – Score ryanpeikou as a 3-han yaku.
- Nashi – Ryanpeikou is not used. In this case the hand will score two iipeikou for 2 han.
Ryuuiisou
A limit may be imposed on ryuuiisou to include or exclude hatsu.
- Incl – Include hatsu
- Req – Require hatsu
- Excl – Exclude hatsu
Tenhou and chiihou
Score a self-drawn win within a hand's first uninterrupted go-around as a yakuman.
- Aari – Score tenhou and chiihou as yakuman.
- Nashi – Score these wins as normal hands.