Riichi Mahjong Primer

This article will attempt to describe how to play riichi mahjong (Japanese Mahjong) online in a clear and concise way. For the sake of brevity, any instructions related to setting up the game are omitted for this guide.

This page is split into two sections:

Game rules - How turns work, what the tiles are, how to win hands
Basic/Intermediate strategy - Introducing the strategy around the game

1. Explaining Game Rules

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 hands. A hand ends when a player wins, when the tiles run out, or in certain special conditions.

The gameplay of riichi mahjong is largely similar to other Asia-originated variants of mahjong. If you know Hong Kong or Singaporean mahjong, for instance, riichi mahjong will not be hard to learn.

Compared to American Mahjong, "what you do in each turn" is roughly the same, but the types of winning hands are completely different.
Compared to mahjong solitaire ("single player mahjong"; the game where you match tiles with each other), the gameplay as a whole is completely different; only the tiles are the same.

Turns

A game of mahjong is organized by hands and turns. At the beginning of each hand, you start with 13 tiles. Every turn, you draw a tile, then discard a tile.

During your turn, you can (in order):

Draw 1 tile.
If this tile can complete a winning hand, you may declare a win by self-draw ("Tsumo").
You may declare special actions (kan / 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.

After a player wins, the hand ends. After 70 draws, the hand also ends. When the hand ends, tiles are shuffled and a new hand starts.

Players go in counter-clockwise order (East player -> South player -> West player -> North player).

Tiles

There are 36 unique types of tiles, and 4 of each type, for a total of 136 tiles. They can be grouped into two major categories:

Number Tiles. There are three suits of number tiles, where each suit has tiles from 1-9. Number tiles 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 of this suit is a bird. The other tiles are green lines, the number of lines is the number of the tile.

Honor Tiles. Each honor tile 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 4 cardinal directions. In order, they are East, South, West, North. Knowing the direction of the wind tiles *is* important. Like the character tiles, the winds can be labelled E S W N in the top right corner if the website allows.

Winning hands

In order to win, a hand needs to match BOTH of these two conditions:

1. It needs to have a winning shape. The most common winning shape is "4 groups of three + 1 pair". (This is 14 tiles long by default. However, you can only hold 13 tiles at a time. This means you need to get a 13-tile "ready hand", then obtain the 14th tile.)
2. It needs at least 1 yaku. Yaku are equivalent to points. You can't win with no points, so you can't win with no yaku. You need at least 1 point to win.

Both of these conditions will be covered in the following sections.

Winning shape

A winning shape is "4 groups of three + 1 pair", with a few special exceptions that beginners do not need to know about.

Groups of three

"Groups" (also called "melds") include sequences and triplets.

Sequences: Sequences are three number tiles in sequential order, and of the same suit.

Closed		Open

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.

Triplets: Triplets are three copies of the same tile. Any tile can be used in a triplet.

Closed		Open

Pairs

Pairs are two copies of the same tile, similar to a triplet.

Pair

Example winning hand

An example of a winning hand:

This hand has:

4 groups - 2 sequences ( ) + ), 2 triplets ( ) + )

1 pair ( )

Ready hand

A winning hand is 14 tiles long, but you can only hold up to 13 tiles. This means you must get a 13 tile "ready hand" (tenpai), then obtain the last tile by drawing it or another player's discard.

Ready hand #1 - 3 complete groups + 1 incomplete set + 1 pair:

Waiting for:

3 groups - 1 sequence ( )), 2 triplets ( ) + )

1 pair ( )

1 incomplete group ( )

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 groups + 1 tile waiting to be paired:

Waiting for:

4 sets - 2 sequences ( ) + ), 2 triplets ( ) + )

1 tile waiting to be paired: ( )

It may win off , to complete a pair.

Yaku

In addition to having a winning shape, you need at least 1 yaku to win. There are 26 distinct yaku. As a new player, only three of these yaku are "must-knows". These are the three most common yaku in the game.

Riichi

You may declare riichi when BOTH of these conditions are met:

The hand is closed - it has not declared chii, pon, or a kan.
You'd have a ready hand once discarding a tile.

Riichi also requires a bet of 1000 points (given to the next player who wins a hand), prevents you from changing your hand, and announces to others that you have a ready hand. However, riichi is extremely powerful. Riichi is 1 han yaku on its own, and gives chance to score random bonuses (ippatsu and ura dora). Due to these random bonuses, riichi is worth 1.5 han on average.

Tanyao

Tanyao ("All Simples") is scored if the hand has no 1's, 9's, or honors. In other words, it only has tiles numbered 2-8. It does not matter if your hand is open or closed.

The above hand scores tanyao since it does not have a 1, 9, or honor tile.

Yakuhai

Yakuhai ("Value tiles") are scored by having ANY of the following:

A triplet of any dragon tile ( , , )
A triplet of a wind tile that matches your seat wind. For example, if you're the West seat, a triplet of the West wind tile is yakuhai.
A triplet of a wind tile that matches the round wind. For example, if it's the East round, a triplet of the East wind tile is yakuhai.

(It doesn't matter what the rest of the hand is, so long as it's the "4 groups + 1 pair" winning shape. A hand can score multiple yakuhai at once. If a wind tile is both the seat and round wind, it is worth 2x yakuhai, for 2 han.)

Why these three yaku are so important

Whether your hand is open or closed, you can rely on riichi, tanyao, or yakuhai:

Closed hands: All closed hands have the option to declare riichi.
Open hands: Even in the highest levels of play, over 90% of open hands have either tanyao or yakuhai.

Closed hands can 100% rely on riichi, and open hands can 90% rely on tanyao/yakuhai, so knowing these three yaku has the greatest returns.

Riichi mahjong is heavily centered around "cheap and fast" yaku. This is because of dora (bonus tiles), which can add lots of value for even the cheapest hands. Therefore, many expensive hands are formed around stacking riichi + dora, rather than going for yaku.

Tile Calls

Chii and pon are tile calls. They allow you to steal tiles from other players' discards, but cause your hand to be open (preventing riichi).

Chii: The call to complete a sequence. Chii may be called when you have 2 tiles that could form a sequence, then your leftward opponent discards a tile to complete the sequence. To restate, chii may only be called from the player to your left.
Pon: The call to complete a triplet. Pon may be called when you have a pair, and any opponent discards a tile. Pon can take tiles from anyone, so it can skip some players' turns.

Remember that you need at least 1 yaku to win (and that open hands can't use riichi to gain that yaku).

Furiten

When you are in furiten, you are completely unable to win off other players' discards. You can still win by self-draw, however, if you have at least 1 yaku.

The most common cause of furiten is when you have previously discarded a tile that your hand could now win with. Example:

Waiting for: , , or

Say you discarded the . You are in furiten, meaning you cannot win off any tile because you could've won with the discarded 2. If an opponent discards , you cannot win, even though you never discarded that tile.

It does not matter which tile "caused" the furiten. If you are in furiten, you cannot win off any tile.
It does not matter if you couldn't win off the discarded tile due to a lack of yaku. If a tile could complete the "4 group + 1 pair" shape, it triggers furiten, even if you couldn't actually win with said tile.

Dora

Dora are bonus tiles. Every dora in hand is worth +1 han. However, you still need at least 1 yaku to win, no matter how many dora you have.

At the start of each round, a dora indicator is revealed. The tile after the revealed dora indicator is the dora tile itself.

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)

For each kan a player makes, a new dora indicator is revealed. If the new dora indicator is the same as another, then the specified tile is worth aother han.

Remember: A hand cannot win with no yaku, even if it has dora. A hand needs 1 yaku to win.

Uradora

If you declare riichi and win, the uradora are revealed. 1 uradora indicator is revealed for each regular dora indicator. Uradora indicators work like dora indicators (the tile after the indicator is the dora tile).

There is no way to know uradora before winning, so yradora are essentially random bonuses for winning with riichi. In general, ~30% of winning riichi hands contain at least 1 uradora.

Red Fives

In most modern riichi mahjong websites, red fives are used. There is one red five in each suit (a red 5 of characters, a red 5 of bamboo, a red 5 in dots).

Having the red five in your hand is worth extra points, just like a dora tile. Unlike dora, having the red five in your hand gives you value. (I.e. a red five in your hand does not make a 6 more valuable.)

If a red five is the dora/uradora indicator, nothing special happens; the 6 of that suit is still a regular dora as usual.

Rounds & Hands

The game is organized into rounds and hands.

Hands: Hands start when tiles are dealt, and ends once someone wins. After the end of each hand, if no repeat occurs, the player seats are rotated counter-clockwise.
Rounds: Each game starts in the East round. A round ends once players rotate seats 4 times, meaning East round lasts from East 1-4.

When starting a mahjong game, you have the choice between "East Round only" (tonpuusen) or "South Round" (hanchan). East Round games last for 1 round; South Round games last for 2 rounds.

Dealer

The player in the East seat is known as the dealer, who gets special benefits:

Dealer hands are worth about +50% points.
If a dealer wins, or has a ready hand at exhaustive draw, they repeat the hand (renchan). (A repeat means they get to extend the entire game by +1 hand, while retaining the dealer seat.)

When does the game end?

The game itself ends under these two scenarios:

A player falls below 0 points.
It is the end of East 4 (East Round only) / South 4 (South Round (hanchan)), no dealer repeat occurs, and at least one player is at/above the target score.
- If nobody hits the target score, a maximum of 1 wind round of overtime occurs. If a player reaches the target score, the game immediately ends. If a round passes and nobody hits the target score, the game also ends.

Keep in mind that, every time the dealer wins, the game is extended by 1 hand.

Why can't I win?

There are three main reasons why you cannot win a hand:

Not a winning shape: A hand needs 4 groups + 1 pair to win (with a few exceptions).

No yaku: A hand with 0 points cannot win. Therefore, a hand cannot win without a yaku. Even with dora, you still need at least 1 yaku.

Furiten: When you have discarded a tile that your hand can now win with, you enter furiten. When furiten, you cannot win by ron (i.e. cannot win by another player's discard). You can still win by drawing your own tile, assuming you have a yaku.
- When you are in furiten, you cannot ron off any tile, regardless of which tile "caused" furiten.
- Furiten doesn't care if you couldn't win due to not having yaku. If you've discarded a tile that could complete a "winning shape", you're in furiten.

User:Hordes/Riichi Mahjong Primer - Shorter

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