Ooyamaneko.net

Several yaku require the hand to be closed. A closed hand can be won on a discard. If the discarded winning tile finishes a kōtsu, the kōtsu is considered melded when scoring the minipoints, but the hand as such is still closed.

The yaku are cumulative unless specified otherwise, so several yaku may be combined in the same hand.
Yakuman yaku are not cumulative.

Riichi — Riichi — [The hand must be closed]
Closed waiting hand declared at 1000 points stake.

The player must declare riichi by clearly saying "riichi", rotating the discarded tile sideways and paying 1000 points to the table by placing a stick by the discards.

If an opponent claims the rotated discard for winning, the riichi declaration is voided and the 1000 points are returned to the riichi declarer. If an opponent claims the rotated tile for a melded group, the riichi declarer must rotate his next discarded tile.
A player is not allowed to declare riichi if there are less than four tiles left in the wall.

A player who declared riichi can no longer change his hand. However, he may declare a concealed kantsu if he draws a tile matching a concealed kōtsu, if this does not change the waiting pattern and if the three tiles can only be interpreted as a kōtsu in the original riichi hand. (E.g. in case of three consecutive kōtsu in the same suit, no kantsu may be declared, since the tiles can be interpreted as three identical shuntsu).

It is permissible for a player who is furiten to declare riichi.

Ippatsu — Ippatsu — [The hand must be closed]
A player who declares Riichi will be rewarded for Ippatsu if he wins during the next uninterrupted set of rounds, including if he wins by self-draw on his next draw.
Calls for shuntsu, kōtsu or kantsu, including concealed kantsu declarations, interrupt the round, making Ippatsu invalid. Riichi declarations do not interrupt the round.

Double Riichi — Daburu riichi — [The hand must be closed]
A player who declares Riichi during the first un-interrupted set of turns will be rewarded for Double Riichi.
Calls for shuntsu, kōtsu, kantsu and concealed kantsu declarations interrupt the round, making later Double Riichi invalid. Riichi declarations do not interrupt the round.

Fully Concealed Hand — Menzen tsumo — [The hand must be closed]
Winning on a self-draw on a closed hand.

Pinfu — Pinfu — [The hand must be closed]
A pinfu hand is a hand worth no minipoints beside the 20 minipoints for winning and the 10 minipoints for winning on a discard on a closed hand. The 2 minipoints for winning by self-draw can be omitted to qualify as a pinfu hand in order to score the pinfu yaku.

The pinfu yaku is awarded for winning on a closed pinfu hand. I.e. a closed hand with four shuntsu and a pair that is neither dragons, nor seat wind, nor prevailing wind; the winning tile completing a shuntsu with a two-sided wait.

Pure Double Shuntsu — Ii peikō — [The hand must be closed]
Closed hand with two completely identical shuntsu, i.e. the same values in the same suit.

All Simples — Tanyao chū
Hand with no terminals and honours. The hand can be open or closed.

Yakuhai — Yakuhai
Kōtsu or kantsu of dragons, the player’s seat wind or the prevailing wind.
Multiple yakuhai combines.
If the player’s seat wind is the same than the prevailing wind, a kōtsu or kantsu of this wind scores yakuhai twice.

Robbing a Kantsu — Chan kan
Winning on a tile that an opponent adds to a melded kōtsu in order to make a kantsu. Since the kantsu is not declared successfully, no kan dora is revealed.
Counts as a win on a discard.
Robbing a Kantsu also applies when winning on Thirteen Orphans on a tile used by an opponent for making a concealed kantsu. A concealed kantsu can only be robbed in the case of Thirteen Orphans.

After a kantsu — Rinshan kaihō
Winning on a replacement tile after declaring a kantsu.
Counts as self-draw; the two minipoints for winning on self-draw are awarded.

Last Tile Draw — Haitei
Winning on self-draw on the last tile of the wall.
If the last tile of the wall is a replacement tile drown after a kantsu, only After a Kantsu will be scored. I.e. you can not score Last Tile Draw and After a Kantsu together.

Last Tile Claim — Hōtei
Winning by claiming the discard after the last tile of the wall.

Seven Pairs — Chii toitsu — [The hand must be closed]
Closed hand with seven different pairs. Two identical pairs are not allowed.
Seven Pairs always scores exactly 25 minipoints; extra minipoints for e.g. a pair of dragons is not awarded.

Pure Straight — Ikkitsukan / Itsu — [Worth only one han if the hand is open]
Hand with three consecutive shuntsu in the same suit.

Mixed Triple Shuntsu — San shoku dōjun — [Worth only one han if the hand is open]
Hand with three shuntsu of the same numerical sequence, one in each of the three suits.

Outside Hand — Chanta — [Worth only one han if the hand is open]
All groups contain terminals or honours, and the pair is terminals or honours.
The hand must contain at least one shuntsu.

All Kōtsu — Toitoi hō
Hand with four kōtsu and/or kantsu and a pair.

Triple Kōtsu — San shoku dōkō
Hand with three kōtsu and/or kantsu, one in each suit, of the same number.

Three Concealed Kōtsu — San ankō
Hand with three concealed kōtsu and/or kantsu.
Note that the entire hand is not required to be closed.

Three Kantsu — San kantsu
Hand with three kantsu.

All Terminals and Honours — Honrōtō
Hand containing only terminals and honours.
Add two yaku for All Kōtsu or Seven Pairs.
Does not combine with Outside Hand.

Little Three Dragons — Shō san gen
Hand with two kōtsu and/or kantsu of dragons and a pair of dragons.
Add the two yaku for the individual kōtsu / kantsu of dragons.

Twice Pure Double Shuntsu — Ryan peikō — [The hand must be closed]
Closed hand with four shuntsu which two and two form Pure Double Shuntsu.
Does not combine with Pure Double Shuntsu.

Half Flush — Honitsu — [Worth only two han if the hand is open]
Hand with tiles from only one of the three suits, in combination with honours.

Terminals in All groups — Junchan — [Worth only two han if the hand is open]
All groups contain terminals, and the pair is terminals.
The hand must contain at least one shuntsu.
Does not combine with Outside Hand.

Blessing of Man — Renhō — [The hand must be closed]
Winning on a discard in the very first un-interrupted set of turns, before the player has had his first turn.
Calls for shuntsu, kōtsu or kantsu, including concealed kantsu declarations, interrupt the round, making later Blessing of Man invalid. Riichi declarations do not interrupt the round.
Blessing of Man is cumulative with other yaku and dora.

Full Flush — Chinitsu — [Worth only five han if the hand is open]
Hand composed entirely of tiles from only one of the three suits, without any honours.
Does not combine with Half Flush.

Blessing of Heaven — Tenhō — [The hand must be closed]
East player winning on his initial dealt tiles.
Not valid if the player declares a concealed kantsu.

Blessing of Earth — Chihō — [The hand must be closed]
Winning on self-draw in the very first un-interrupted set of turns.
Calls for shuntsu, kōtsu or kantsu, including concealed kantsu declarations, interrupt the round, making later Blessing of Earth invalid. Riichi declarations do not interrupt the round.

Thirteen Orphans — Kokushi musō — [The hand must be closed]
Closed hand with one of each of the thirteen different terminal and honour tiles, plus one extra terminal or honour tile. The hand can be completed on any tile; it does not need to be waiting on thirteen different tiles.

Nine Gates — Chūren pōtō — [The hand must be closed]
Closed hand consisting of the tiles 1112345678999 in the same suit plus any one extra tile in the same suit. The hand can be completed on any tile; it does not need to be waiting on nine different tiles.

Four Concealed Kōtsu — Sū ankō
Hand having four concealed kōtsu and/or kantsu.
I.e. a closed hand with four concealed kōtsu, completed by self-draw or by claiming a tile to complete the pair.

Four Kantsu — Sū kantsu
Hand with four kantsu.

All Green — Ryū iisō
Hand composed entirely of green tiles. Green tiles are: green dragon and 2, 3, 4, 6 and 8 of bamboo. The hand is not required to include the green dragon.

All Terminals — Chinrōtō
Hand composed entirely of terminal tiles.

All Honours — Tsu iisō
Hand composed entirely of honour tiles.

Big Three Dragons — Daisangen
Hand with three kōtsu and/or kantsu of dragons.
A player feeding the last kōtsu or kantsu may be subject to liability payment.

Little Four Winds — Shōsūshi
Hand with three kōtsu and/or kantsu of winds and a pair of winds.

Big Four Winds — Daisūshi
Hand with four kōtsu and/or kantsu of winds.
A player feeding the last kōtsu or kantsu may be subject to liability payment.