[[Image:YakuListed.png|thumb|right|300px|[http://tenhou.net/0/?log=2008121721gm-00c1-0000-fcadb0d7&tw=3&ts=5 Example hand], containing many yaku.]]
[[Image:YakuListed.png|thumb|right|300px|[http://tenhou.net/0/?log=2008121721gm-00c1-0000-fcadb0d7&tw=3&ts=5 Example hand], containing many yaku.]]
A '''[[yaku]]''' {{kana|役}} is a certain pattern in a mahjong hand that scores points, and a necessary condition for winning (analogous to hands in poker). A hand can score multiple yaku at once. Under standard rules, there are 26 different yaku and 11 [[yakuman]] (a special class of high-scoring yaku). In addition, one special case may be allowed in [[nagashi mangan]].
A '''[[yaku]]''' {{kana|役}} is a certain pattern that scores points, and a necessary condition for winning. They are analogous to hands in poker. In total, there are 26 yaku, 11 [[yakuman]] (a special class of high-scoring yaku), and 1 special case in [[nagashi mangan]].
'''In order to win any hand, the hand must have at least one yaku.''' Even if a hand has [[dora]], it cannot score without a yaku. Declaring a win without yaku can score a [[chombo]] penalty. Therefore, when learning the game, it is essential to learn the different types of yaku.
Each yaku is worth a specified amount of '''[[han]]''', where rarer yaku are generally worth more. A hand can score multiple yaku at once. When a hand is won, its han (from both yaku and dora) are added up, and the total han value is converted into points using a [[scoring table]].
Each yaku has a specified amount of '''[[han]]''' {{kana|飜}}, where rarer yaku are generally worth more han. Han can also be increased by acquiring dora, but dora do not count as yaku for the purposes of winning. A hand's total han value, counted from adding up yaku and dora, [[Scoring table|determines the points]] you'll get in the end.
'''In order to win any hand, the hand must have at least one yaku.''' Even if a hand has [[dora]], it cannot score without a yaku. Attempting to win without a yaku is subject to a [[chombo]] penalty, so it is important to learn the yaku, or at least the most common types.
The most important yaku to learn is [[riichi]]: it is the most common yaku and very easy to achieve. Any hand that isn't [[open]] may declare riichi when [[tenpai|about to win]]. A beginner may rely solely on riichi, though it is important to learn the other yaku too.
The most important yaku to learn is riichi: it is the most common yaku and very easy to achieve. Any hand that isn't open may declare riichi when about to win. A beginner may rely solely on riichi, though it is important to learn the other yaku too.
A yaku「役」 is a certain pattern that scores points, and a necessary condition for winning. They are analogous to hands in poker. In total, there are 26 yaku, 11 yakuman (a special class of high-scoring yaku), and 1 special case in nagashi mangan.
Each yaku is worth a specified amount of han, where rarer yaku are generally worth more. A hand can score multiple yaku at once. When a hand is won, its han (from both yaku and dora) are added up, and the total han value is converted into points using a scoring table.
In order to win any hand, the hand must have at least one yaku. Even if a hand has dora, it cannot score without a yaku. Attempting to win without a yaku is subject to a chombo penalty, so it is important to learn the yaku, or at least the most common types.
The most important yaku to learn is riichi: it is the most common yaku and very easy to achieve. Any hand that isn't open may declare riichi when about to win. A beginner may rely solely on riichi, though it is important to learn the other yaku too.
Any closed hand that reaches tenpai may declare "riichi" to score this yaku. Declaring riichi requires you to bet 1000 points, and announces you are in tenpai.
Have sequences of "123", "456", and "789", all of the same suit, appearing as "123456789". Simply having every tile from 1-9 is not enough; the hand must have those exact sequences.
Three closed triplets (and/or quads). Each of the three triplets must be formed without calling any tiles; a triplet completed by ron does not count as closed. The fourth group can be an open triplet or sequence.
Every tile is either a terminal or an honor tile. † This hand may be considered as 4 han, because it is impossible to score this hand without either chiitoitsu or toitoi.
Two triplets (and/or quads) of dragons, and a pair of the third dragon. † This hand may be considered as 4 han, because it is impossible to score this hand without two sets of yakuhai, from the two dragon triplets.
This hand has one of each of the 13 different terminal and honor tiles, plus one extra terminal or honor tile. Some rules may allow double yakuman for a 13-wait set.
A non-dealer has a winning hand by their first draw. In addition, no player can make tile calls before then.
Special case
This yaku does not specifically deal with a player's hand, but rather the player's discards. In addition, the hand may or may not be at tenpai upon scoring. The result of nagashi mangan modifies the case of ryuukyoku, where point exchanges equate to mangan.
The above list is generally considered as the "standard yaku", including the yakuman. However, the game offers an even larger array of tile patterns. Various house rules may opt to use some of these yaku on their own.
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Agari: 
Agari: 