Gamehelpriichimahjong

Goal of a hand

The game is played with a set of 136 tiles based on Chinese characters and symbols. Each player begins by receiving 13 tiles. In turn players draw in the wall until they complete a legal hand using the 14th drawn tile to form four melds and a pair but need a yaku to officially win the hand. A player can also win with 2 other kinds of hands. The dead wall is composed of 14 tiles, 4 only available to compensate Kong and 10 bonus tiles (Dora).

Tiles

Tiles are split in 3 suits with tiles numbered 1 to 9 and honors

Simples are the tiles numbered 2 to 8 in each suit

Terminals are the numbered 1 and 9 in each suit

Honors are divided into Winds and dragons

Play order

The dealer (East) plays first then play order is counterclockwise with the 2nd player being South, 3rd West and last player North

Calls

Most calls open the players' hand, they are

Chi: Can only be called from the player just before them in turn order, completes a 3 tile sequence

Pon: Can be called from any player, completes a triplet

Kan: There are three kinds of quads (called by Kan): An open quad called directly much like a pon, a Pon converted into a kan, and a closed kan which comes entirely from their hand (latter does not open hand). In all cases, a replacement tile (the rinshan) is drawn from the dead wall and a new dora is revealed.

Dora (bonus tiles)

The dora indicators are part of the 14 tile dead wall, and 1 is revealed at the start of each round. The tile 1 rank over the indicator in the same suit then becomes dora. 9 wraps back to 1, if indicator is a wind, it goes ESWN, wrapping back just like player order. For dragons it goes by Japanese alphabetical order (chun (Red), haku (White), hatsu (Green)), wrapping back.

Riichi

Just as the name of the game implies, a player can call riichi if they haven't done any calls, with the exception of a closed kan, and their hand is ready (tenpai). Riichi costs 1000 points.

Winning a hand

To win a hand, a player's 13 hand tiles and the tile they draw or any discard must form a hand of 4 melds of 3 tiles and a pair, and have a yaku. The 2 different compositions of the hands are yakus themselves.

Tsumo: Winning by drawing the tile needed to complete the player's hand Ron: Winning off a discard of somebody else, or robbing a kan

In both cases if a non-dealer wins, honba is reset to 0, if dealer wins, 1 honba is added (literally a repeat).

Furiten

If any of the tiles a player discarded would complete his/her hand, this hand becomes furiten (sacred discard). If this happens the concerned player can only win by tsumo. Note that skipping a ron gives temporary furiten, except if skipping a ron while in riichi where the player can't ron anymore, then player is forced to tsumo.

Value calculation

Once a hand wins, it's time to calculate the points of that player.

Each yaku gives the corresponding number of han, and fu is then calculated

A win is a base 20 fu to which these bonuses add up if condition applies:

Closed ron:10

Tsumo: 2 (pinfu excluded)

Fu given for hand itself:

Sequence: Nothing

Same tile meld:

Open triplet of simples:2

Open triplet of terminals:4

Closed meld: double

Quad: multiply by 4

If the pair would be yakuhai, that's 2 points, 4 in case of a double wind yakuhai pair.

If wait is on a pair 2 extra fu.

Then if result doesn't end by 0, it is rounded always up to the next 10

Base value calculation then follows with this formula:

Base value=fu*2^(han+2)

If a non dealer wins by tsumo, dealer pays 2 times the base value, others pay the value itself If non-dealer by ron: All the payments for a total of 4 times fall upon the discarding player itself. Dealer tsumo: The other players pay 2 times the value Dealer ron: All the payments for a total of 6 times fall upon the discarding player itself.

The actual payment to the winner gets rounded up to a unit of 100

1 to 4 han: calculated, but if clear that 3 han 70 fu or 4 han 40 fu then skip to next value, because it goes over the 2000 limit. 5 han: mangan, fixed base value of 2000 (not calculated) 6+ han: haneman, 3000 base 8+ han: baiman, 4000 base 11+ han: sanbaiman (lit. triple mangan), 6000 base 13+ han: Natural limit (kazoe), 8000 base value Limit hand (Yakuman): Same as 13+ han but multiple limits can stack

The winner also takes all riichi sticks that are unclaimed and on the table, and gets 100 points per player (300 from discarding player if ron) for each honba

Draw hands (ryuukyoku)

A draw occurs in the following cases and a honba (repeat counter, 100 point stick) is added:

If the wall has only 14 tiles left, a player can't kan that tile and must either call tsumo or discard. Likewise after the discard the other players get a last chance to call ron. Pon and chi are not valid on the last tile. If no win is declared then it goes into a draw.

Then depending on the tenpai players:

1 tenpai: Player gets 1000 from each player 2 tenpai: Each player gets 1500 from the non-tenpai (noten) players 3 tenpai: The tenpai players each get 1000 from the last player All noten or 4 tenpai: No exchange Note that if a player discards all terminals and doesn't get called, then a nagashi (usually mangan) payment overwrites these. Multiple nagashis work in a similar way to 1 player getting nagashi.

Abortive draws (before the end of a hand) (tochuu)

Those draws start a new hand immediately without payments and no wind change is made

Called in the first turn without calls

=====Nine different terminals and honors aka Nine terminal draw (kyuushu (kyuuhai))

As the name implies, starting hand has 9 or more different terminals and honors. This draw is optional.

Four winds draw (suufon renda(lit. four wind repeat))

In the first turn, all 4 players discard the same round wind, they "repeat" the wind

Any turn into the hand

=====Four quads (Suukaikan)

This case only applies if multiple players have called kans, if only 1 player called all 4 kans, the player can go for a 4 kan win and hand is not aborted. In case of an open kan a final discard is required to pass (can still be ronned) before the draw is declared

=====Four riichis (Suucha riichi (lit. 4 player riichi))

All 4 players call riichi and the 4th riichi passes, 4th riichi can be ronned on.

Triple ron (sanchahou)

All 3 other players call ron on the same tile from a player.

Yakus

Based on the situation of the win (1 han for most of them)

Riichi

Player has called riichi and won the hand. In this case, they get access to ura doras, a second set of dora tiles under the regular dora indicators.

Double reach (daburii)

Same as riichi but called on first turn before any other calls are made (1 more han than a regular riichi, therefore, double the riichi han count)

One-shot (ippatsu)

Winning on the turn a player called riichi/daburii as long as no other calls are made (so no riichi makes ippatsu not count)

Robbing a kan (chankan)

A player can rob a kan if it has been promoted from a triple (with the exception of a certain limit hand (yakuman))

Dead Wall draw (rinshan kaihou)

If the tile a player draws after calling any kan completes their hand, this yaku is awarded.

====Closed hand Tsumo (aka fully closed hand)((menzen) Tsumo)

Tsumo on a closed hand, all 14 tiles are closed in that case (closed kan is still considered closed do qualifies even though 2 tiles have their value revealed.

Last tile win

On draw (Haitei (raoyui))

Win on the last drawn tile from the wall

=====On discard(Houtei (raoyue))

Win on the last tile that would be discarded this hand

Based on hand composition

All of these amounts considered closed hand value, kuisagari means lose 1 han if open

A kan also counts as a triplet

1 han

No-points hand (Pinfu)

The hand is closed, composed entirely of runs and has it's pair already made for a 2 or 3 tile open wait, the player is not waiting on a pair with similar conditions. In this case the hand gives no fu itself.

2 identical sequences (iipei(kou))

1 set of 2 identical sequences, hand must be closed for this to count

All simples (Tanyao)

Hand is composed entirely of simples (2 to 8 in any suits) (kuitan open)

Dragon triplet (yakuhai)

A triplet of dragons (haku (white), hatsu (green), chun (red)). Note that 2 triplets stack for 2 han.

Seat/round wind (Bakaze/jikaze/kazehai)

A wind triplet fitting the round's wind or a player's seat wind. In the case it fits both, that's 2 han stack for double (wind) (dabuton, dabunan, dabusha)

2 han

Seven pairs (chiitoitsu)

The hand is composed of 7 pairs. Closed by definition, bc no pair calls exist, non-standard composition hand. gives fixed 25 fu. Not to be confused with 2 sets of identical sequences (when 2 sets of 3 pairs follow each other), which score differently.

All triplets (toitoi(tsu))

Hand is composed of 4 triplets and a pair, no value loss if open

Three color straight (sanshoku (doujun))

The same run in all 3 suits. This hand is subject to kuisagari (-1 han if open)

=====Three color triplets (sanshoku doukou, sandoukou)

Similar to three color straight, but this time with triplets. No value loss for opening.

Full straight (iittsuu, ikkitsukan)

The hand is composed of 123456789 in a single suit. Note that since mahjong uses only 3 tile runs, there must be 123, 456 and 789 sequences for this to count. Kuisagari applies.

Half Outside hand (Chanta(iyaochuu))

A hand composed of melds with terminals and honors. Note that a run must be present otherwise it turns into All Terminals and Honors. Subject to kuisagari

All Terminals and Honors (Honrou(tou))

Like half outside but with all triplets. Note that in this case hand is at least mangan because All triplets also apply. No value loss.

Little Three Dragons (shousangen)

A triplet of 2 of the 3 dragons + a pair of the third. This hand also gets the 2 han for the 2 dragon triplets. No value loss.

Three concealed triplets (sanan(kou))

Three triplets directly in a player's hand which you haven't called, and are not part of a run themselves. No value loss.

Three quads (sankantsu)

Three quads, any work but if closed can combine with three concealed. No value loss.

3 han

Twice Double Pure Sequence (ryanpei(kou))

2 sets of identical sequences, hand must be closed. Not to be confused with 7 pairs, since highest value must always be counted.

Half Flush (honitsu)

All tiles are in a single suit and honors are present. Kuisagari applies (-1 han if open)

True Outside Hand (junchan(taiyaoo))

Like half outside, but without honors. If hand is composed of triplets, it becomes all terminals, a limit hand. Kuisagari applies(-1 han if open)

6 han

Full flush (chinitsu)

Like half flush but without honors. Like Half Flush, kuisagari applies (-1 han if open)

Limit hand

Heavenly hand (Tenhou)

Dealer has a full hand with its initial tiles

Earthly Hand (Chihou)

Same as Tenhou, but non-dealer and no calls made

Big Three Dragons (daisangen)

A triplet of all 3 Dragons

Four Quads (suukantsu)

Four quads, any count. If those 4 kans are closed, this can stack with 4 concealed triplets and in this case is also pair wait for a possible triple limit.

All Green (Ryuuiisou)

Hand is composed of tiles that are entirely green (hence the name). Those are: 23468 of bamboo and the green Dragon. Not necessarily all triplets, can have a 234 run.

All honors (tsuuisou)

Hand composed entirely of honors. This hand can be 7 pairs because 7 different honors exist.

All terminals (chinroutou)

Hand composed entirely of terminals. Only available in all triplets because 6 different terminals

Thirteen orphans (kokushi (musou))

1 of each terminal and honor and a copy of one of them. If the pair is there, it's a single. (Can rob a closed kan, only case where a player can do that).

If the pair is waiting to be completed, it's a double (true or the best 13-wait kokushi).

Four concealed triplets (suuankou)

Single version: Hand is fully closed and is composed of all triplets.

Double version (suutan, suuankou tanki): 4 triplets are already in a player's hand and they are waiting for a single tile, can be ronned off of.

Nine gates (chuuren (poutou))

A hand which is composed of 1112345678999 and a copy of any tile on the same suit, Nine Gates come from the fact that hand can be completed with 9 tiles and form a valid hand. Must be closed.

Single version: A player either has all 1s or 9s of a suit in the deck or they have a pair of another number while still having the rest to get the corresponding hand, in this case single wait.

Double version (true or 9 wait nine gates): A player's hand is 1112345678999 giving you the full 9 tile wait.