Riichi

Riichi

Type	Yaku
Kanji	立直 or リーチ
English	Ready hand
Value	1 han (closed only)
Speed	Varies
Difficulty	At discretion

Riichi 「立直」 or 「リーチ」 is the most common yaku in the game. Any closed hand that reaches tenpai can declare "riichi", gaining this yaku. It occurs in ≥40% of winning hands across various platforms and professional settings.

Declaring riichi is not mandatory. Players may decline to declare riichi, keeping the hand's tenpai status hidden - this is a tactic known as damaten. Various factors should be considered before calling riichi, such as current point standing and available tiles.

Rules

Riichi may be declared when:

• The hand is closed - no chii, pon, or open kan has been made.
• The hand is tenpai - it is one tile away from winning.
• The player must have at least 1,000 points (unless the player is allowed to go into negative points).
• There must be at least 4 tiles left in the live wall. In other words, the player must be able to draw at least one more tile in an uninterrupted set of turns.

To declare riichi, a player announces riichi and discards a tile facing sideways in the discard pile. This is done to indicate when riichi was called. If that tile is claimed by another player for an open meld, then the next discard is turned sideways as a replacement.

Unless the first sideways discard is claimed for a win immediately, the riichi announcer now places a bet of 1,000 points on the table. This bet is collected by the next player to win a hand. Specific rules will differ on what happens if multiple players win, or what happens if the game ends before any player claims the bet.

After a riichi declaration, the hand remains locked and unchangeable. In this state, the player is simply waiting for a winning tile to appear, either by draw or discard. However, there is a notable exception: a riichi player may declare kan in certain circumstances.

In addition to the 1 han from riichi itself, you can score further han through ippatsu and ura dora.

Kan

Main article: Kan#Kan during riichi

It is possible to declare a closed kan after declaring riichi. When this is legal will depend on the ruleset; improper calls may be subject to chombo. Even if the kan is legal, you can choose to not call it.

There are two major rule variations on kan legality:

• Kan is allowed unless one of the to-be-kanned tiles could be interpreted as a sequence or pair if a given winning tile is obtained. E.g. you cannot kan the 2/3/4 with 222333444 in hand, since it could be interpreted as three 234 sequences (the kan would prevent the hand from being interpreted as sequences).
• Kan is allowed unless the kan would change the hand's waits. This means a 222333444 could be kanned, unless it would affect the final wait.
  • In addition, the kan must include a newly drawn tile, so you cannot kan a '5' in 555567 after drawing the 8.

See Kan during riichi for more details.

Furiten

Main article: Furiten

During riichi, a player may be furiten. In this case, the riichi is considered to be a furiten riichi.

In addition, riichi hands are subject to a special type of furiten. After calling riichi, a player may decline to call on a winning tile. However, if a win is declined, then the riichi hand is subject to furiten for the remainder of the round. Thus, all tiles discarded after the riichi declaration (as indicated by the sideways tile) are considered to be guaranteed safe tiles. While it is advised to declare a win on the first opportunity, some plays may require a player not to do so under very specific circumstances. Of course, such play requires caution.

Suucha riichi

Main article: Tochuu ryuukyoku

Suucha riichi (4 player riichi) is an abortive draw that occurs when four players have declared riichi. After the fourth riichi declarer discards a tile, if that tile is not called for a win, the hand ends.

Noten riichi

In real life play, a player may declare riichi without tenpai - this would be a noten riichi 「ノーテンリーチ」, which is highly ill-advised. If the hand results in ryuukyoku, then it is required to reveal the hand. The hand would naturally show noten, which is illegal, and thus subject to a chombo penalty. Likewise, an incorrectly called win would also be subject to chombo. This dubious situation can be escaped if another player wins, another player commits a chombo, or if an abortive draw occurs. Of course, most mahjong software will prevent players from declaring a riichi without tenpai.

Scoring

Two yaku are specifically associated with riichi: ippatsu and double riichi. In addition, ura dora may be scored for any winning riichi hand.

Ippatsu

Main article: Ippatsu

Ippatsu 「一発」 is a separate yaku, but it is dependent on riichi. If, after declaring riichi, the hand wins before the declarer's next discard, then the hand scores ippatsu. Any tile calls, including a player's own closed kan, will invalidate ippatsu.

Uradora

The benefits of uradora. [1]

Main article: Dora

When a riichi declarer wins, the tiles underneath the dora and kan dora indicators are flipped over. These flipped ura dora indicators reveal the ura dora, which, like regular dora, may increase the hands value.

Double riichi

Main article: Double riichi

Double riichi 「ダブルリーチ」 is a special case for riichi. If riichi is declared on the first turn, before the player's discard, then double riichi applies. In addition, no tile calls may have been made before riichi is called. As the name implies, double riichi is worth 2 han instead of 1 han, as a bonus for the initial timing. Due to the added han, and because tenpai is reached on turn 1, a double riichi hand has a huge advantage over others.

Open riichi

Open riichi 「オープン立直」 is an optional yaku which is a modified version of riichi. The mechanics are identical to a normal riichi, except that you must reveal either your entire hand or its tile waits (depending on ruleset). In exchange, an open riichi is worth 1 extra han. Open riichi makes it trivial for other players to defend against your hand, so in general, the intent is to win by self-draw.

As a further optional rule, yakuman may be awarded if any player intentionally plays into the open riichi. If a player unintentionally deals in, i.e. if a riichi player deals into an open riichi, the yakuman is not scored.

Many official organizations and tournaments do not implement any form of open riichi; it is more or less reserved for casual or gambling game settings.

Compatibility

Main article: Yaku compatibility

^ Ippatsu requires riichi to be of any use.

RCH

DRI

IPP

SMO

TAN

PFU

IPK

ITT

YAK

SDJ

SDO

TOI

SNA

SNK

CHA

JUN

RPK

SSG

HRO

HON

CHN

CHI

RIN

HAI

HOU

CHK

RCH

DRI

Riichi can be declared with any closed hand, so riichi is compatible with all other yaku (except double riichi, which is essentially the same yaku).

Once again, the prospect for rinshan kaihou to work with riichi depends on if you can kan during riichi. When playing with real tiles, a player must be aware of whether a kan is legal.

Strategy

Main article: Riichi strategy

Calling riichi is optional, so players should make various considerations before using riichi. This will often depend on the discarded tiles, how early or late in the hand, the hand's value, and the strength of the hand's wait. If possible, a player may opt not to use riichi at all and instead employ the strategy of damaten.

Oikake riichi

A riichi after another player's riichi is known as an oikake riichi 「追いかけリーチ」 ("chasing riichi"). The first player to declare riichi has an inherent advantage, due to being able to win first and possibly intimidating the other players. An oikake riichi, on the other hand, has a better chance to ippatsu ron on the first riichi declarer (since a player in riichi can't defend). If nobody deals in immediately, both players will engage in a "riichi duel".

Karaten riichi

Main article: Karaten

Riichi can be called even if every possible winning tile is rendered unavailable. A hand in this state is rendered as karaten. Such calls may be made by mistake, or intentionally invoked to cause players to defend.

External links

• 立直

Riichi in Japanese Wikipedia

• Yaku, Hai!: Riichi (& Ippatsu & Daburu Riichi)

Osamuko article on riichi.