User:Hordes
Riichi Mahjong Primer
This article will attempt to describe how to play riichi mahjong (Japanese Mahjong) online in a simple and concise way. The set-up instructions will be omitted for this guide.
Game overview
Riichi mahjong is a 4-player tile-based board game with a heavy focus on luck. The goal of the game is to collect the most points.
You gain points by assembling winning hands. Winning hands that meet specific criteria score more points.
Each game is sorted into multiple rounds. For every round, only one player can win. A round ends when a player wins, when the tiles run out, or in certain specific conditions.
Turns
At the start of each round, each player is dealt 13 tiles. The East player always starts the first turn, followed by South, West, and North (in that order).
During your turn:
- Draw 1 tile.
- If this tile can complete a winning hand, you may declare a win by self-draw ("Tsumo").
- You may declare a quad ("kan") if conditions allow and if you want.
- You may declare "riichi" if conditions allow and if you want.
- Discard 1 tile.
After you discard, your turn is over. Other players may call the discarded tile if they can and want to. If the discarded tile is not called, the next player starts their turn.
Tiles
There are 36 types of tiles, and 4 of each type, for a total of 136 tiles. They can be grouped into two major categories:
Number Tiles. Each "suit" of numbered tile has tiles from 1-9. They can be used to form sequences, triplets, and pairs.
- Manzu (Characters) -
- These tiles are labelled in the Chinese characters (equivalent to the Japanese kanji) for 1-9. In online play, you'll often have the option to add 1-9 labels in the corner of the tile.
- Pinzu (Dots, Circles) -
- The number of circles is the number of the tile.
- Souzu (Bamboo, Bams, Sticks) -
- The 1-sou is a bird. The other tiles are green lines, the number of lines is the number of the tile.
Honor Tiles. Each honor tiles has a different character on it. They can be used to form triplets and pairs, but not sequences.
- Dragons
- With dragon tiles, it is not important to know the meaning of the characters are. Thus, they can be referred to as "White", "Green", and "Red" respectively.
- Winds
- These tiles are labelled in the Chinese characters for the winds. In order, they are East, South, West, North. Knowing the wind tiles *is* important. Like the character tiles, the winds can be labelled N S W E in the top right corner if the website allows.
Winning Hands
A winning hand needs to meet two conditions:
- A winning shape. With two exceptions, winning hands are comprised of 4 "sets" + 1 "pair".
- A "yaku". Yaku are conditions that increase your hand's point value. In essence, a hand cannot win with 0 points, therefore a hand cannot win without any yaku.
- (Note: a hand may gain value via "dora" tiles, but if the hand has no value other than dora, it cannot win.)
Both these conditions will be described below.
Winning Shape
First, let's explain what "sets" and "pairs" are.
Sets
Sets, also called "melds", "groups", or "mentsu", are groups of 3-4 tiles of a specific type.
1. Sequences - sequences are three number tiles in sequential order, and of the same suit.
| Closed | Open |
|---|---|
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Sequences may not "wrap around" from 9 to 1, so sequences of 891 or 912 are not allowed. Honor tiles cannot be used in sequences.
2. Triplets - triplets are three copies of the same tile. Any tile can be used in a triplet.
| Closed | Open |
|---|---|
 |
 
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 |
 
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Pairs
Pairs are two copies of the same tile, similar to a triplet.
| Pair |
|---|
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Winning Shape
As mentioned above, with a few exceptions, a winning shape is comprised of 4 sets + 1 pair, for a total of 14 tiles.
Example hand:
4 sets:
- 2 sequences () + )
- 2 triplets () + )
1 pair: ()
However, you can only hold up to 13 tiles at a time. Therefore, you need to get hand that's 1 tile away from winning ("tenpai"), then either win by drawing a needed tile, or claiming it from another player's discard.
Ready Hand (Tenpai)
A ready hand, or a hand in "tenpai", is a hand that is one tile away from winning. Identifying ready hands is important, since a ready hand is required to win.
Ready hand #1 - 3 complete sets + 1 incomplete set + 1 pair:
3 sets:
- 1 sequence ())
- 2 triplets () + )
1 pair: ()
1 incomplete set ()
This hand waits to complete the incomplete set of 56-pin. It may win off of:
- , forming a complete sequence, or
- , forming a complete sequence.
Ready hand #2 - 4 complete sets + 1 tile waiting to be paired:
4 sets:
- 2 sequences () + )
- 2 triplets () + )
1 tile waiting to be paired: ()
It may win off , to complete a pair.
Ready hands may be interpreted in different ways, allowing the hand to win off multiple different types of tiles. For example:
This hand may win off either 
or , to complete a pair.
The section of the hand may be viewed as either ( sequence + tile waiting to be paired) or ( sequence + tile waiting to be paired). Therefore, it can win off either the 4 or the 7.
To Win
When another player discards a tile you can win with, call "ron". You may not declare ron if you are in furiten (see below for details).
When you draw the tile you can win with, call "tsumo".
Yaku
Yaku are specific criteria that gain you points. For example, All Triplets requires all 4 sets to be triplets.To repeat, a hand cannot win with 0 points, therefore a hand must have at least 1 yaku.
A hand can technically gain points with dora tiles. But if a hand has only dora tiles, and no yaku, it still can't win.
The simplest yaku is riichi. So long as you have not called an opponent's discarded tile (you haven't pressed "chii", "pon", and haven't pressed "kan" when it's not your turn), you may declare riichi when you have a ready hand.
More yaku will be covered later in the guide.
Furiten
When you are in furiten, you cannot win off other players' discards. You can still win by self-draw, however.
The most common way to enter furiten is when you previously discarded a tile that you can now complete a winning shape with. For example:
Waiting for: 
, , or
Say you discarded the in the past. You cannot win off any tile because you could've won with the 2-pin. If an opponent discards , you cannot win. You did not discard the , but you discarded a tile you could've won with - therefore, you cannot win with any tile.
It does not matter if the discarded tile wouldn't give any yaku. If you could've completed a winning shape with the tile, you are in furiten.
While furiten may be an annoying mechanic, it helps players defend against others. Because of the furiten rule, any tile another player discarded is 100% safe against that specific player.
Tile Calls
Chii - The call to complete a sequence. First, you need 2 tiles that can complete a sequence. Then, the player right before you (the player to your left) must discard a tile that completes the squence. You may only call chii to the player to your left.
Pon - The call to complete a triplet. You must have 2+ tiles of the same type, then any opponent needs to discard another tile of that type. You may call pon from any player's discard.
After calling chii or pon, you discard a tile immediately, and it becomes the next player's turn. Therefore, when calling pon, you may skip other players' turns.
Usually, you are unable to "swap call" - you cannot discard a tile that would complete the set you just called. For example, if you had call 4-sou with a 23-sou semi-sequence, you cannot discard a 1. If you pon a 5-man, you cannot discard another 5-man.
Kan - Kan is the call to complete a quad. It is complicated - new players don't need to worry about it. For the studious, there are three types of kan.
- Open kan - You have 3 tiles of the same type, then any opponent needs to discard another tile of that type. Works like pon does.
- Closed kan - You have 3 tiles of the same type, then draw the 4th one.
- Added kan - You previously called pon and draw the 4th tile of the same type.
Despite having 4 tiles, a kan is treated as a single set. Whenever you call kan, you draw a new tile, and your hand size increases by 1. Therefore, after 1 kan call, a ready hand will be 14 tiles, and a winning hand will be 15 tiles.
Calling kan will also reveal a new dora indicator. This may increase the value of anyone's hand, not just your own.
Wind Rotations
At the start of the game, players are assigned East/South/West/North randomly.
When the East player wins, the player's seat winds remain the same for the next round. When nobody wins and the East player has a ready hand, the seats also remains the same.
When a non-East player wins, the winds rotate in reverse player order. The East player becomes North. South becomes East. West becomes South. North becomes West.
Game Wind
The game itself has a wind, too. The game starts in the East wind.
After each player has been the East seat once, the game's wind changes. Like player order, the game's wind goes from East -> South -> West -> North.
Because the player seats do not change when the East player wins, whenever the East player does win, the game is extended by one round.
Game Length
A "hanchan" (half game; South game) is the most common length in riichi mahjong. After the South wind ends (8 game rounds minimum), the game ends.
However:
- If a player falls below 0 points, usually the game ends right then and there.
- If no player has reached the "target score" (usually 30,000 points), then the game continues to the West round. After the West round, the game may end (depending on the website) even if the target score is not yet.
Other Game Mechanics
Dealers
The dealer is always the player in the East seat. In online clients, the game is set up automatically, so the dealer does not set up the game. However, being dealer grants various bonuses:
- Dealers gain roughly x1.5 points for every hand they get.
- As mentioned: when a dealer wins, or when the round ends and the dealer has a ready hand, the winds do not change. A dealer can theoretically win forever until a player is bankrupt.
However, when another opponent wins by self-draw ("tsumo"), the dealer pays twice as much as the non-dealers.
Dora
At the start of each round, a dora indicator is revealed. The tile after the revealed dora indicator is the dora tile. For every dora tile in your hand, you gain 1 han.
For example, if is the dora indicator, is the dora. Having in your hand will increase your hand's value.
- Number tiles: , where indicator means is the dora.
- Dragons: -> -> ->
- Winds: -> -> -> -> (the same as the player order)