Yaku

Yaku 「役」 are specific hand patterns or conditions needed in order to score a hand. In a sense, they are synonymous to "poker hands". Yet, unlike poker hands, yaku are worth specific "han values"; and various yaku may be combined together into one hand. basic mahjong knowledge involves learning the yaku, but it is not expected of new players to know them.

Most importantly, every hand must include at least one yaku, in order to count as a winning hand.

Han

Main article: Scoring

Each yaku is assigned han values. Most have static values, regardless of the hand being closed or open. However, some decrease in han value while being open. Furthermore, some also require hands to remain closed in order to count. For hands to maximize the total han value, different yaku may be combined into a single hand.

Open vs closed

Main article: Kuisagari

Various yaku are affected by the hand's state of being open or closed. After using the different tile calls, a yaku may be affected in terms of han value or even validity. Various yaku, and even yakuman, are restricted to be closed only. Others, they remain valid but their value is decreased by 1-han. As for the rest, it is irrelevant whether the hand is open or closed.

Yaku types

The different yaku focus on different types of patterns and circumstances.

Circumstantial

Two yaku specifically are based on the current state of tenpai, as well as particular actions of other players.

• Chankan - Calling kan with a winning tile.
• Houtei raoyui - Discarding an unsafe tile as the last discard, which happens to be a winning tile.

Luck based

• Ippatsu
• Haitei raoyue
• Rinshan kaihou

Sequential

• Chanta
• Iipeikou
• Ittsu
• Junchan
• Pinfu
• Ryanpeikou
• Sanshoku

Triplet

• Honroutou
• Sankantsu *
• Sanshoku doukou
• Shousangen
• Toitoi

Number based

• Honroutou
• Iipeikou
• Ittsu
• Junchan
• Ryanpeikou
• Sanshoku
• Sanshoku doukou

Honor based

• Shousangen
• Yakuhai

Special case

• Nagashi mangan

Yakuman

Main article: Yakuman

Yakuman is a special class of yaku, by which the pattern itself is awarded the maximum point limit for a single hand pattern.

Combining yaku

Main article: Yaku compatability

Different yaku may be implemented into a single hand. By doing so, the values applied to the different yaku also combine. In short, they stack. This aspect of the game is key towards developing larger scoring hands. With dora, the stacking effect becomes even greater.

External links

• 役_(麻雀)

Yaku in Japanese Wikipedia

• Yaku frequency among Tenhou.net players (Japanese)

Lists all the yaku occurrences in Tenhou.net by percentages and by room

• Yaku short list

Pointing out which yaku to learn first