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'''Riichi''' {{kana|立直}} or {{kana|リーチ}} is the most commonly used [[List of yaku|yaku]] in the game. This yaku may apply to any closed hand and [[Naki|may be declared]] upon achieving [[tenpai]]. Due to its common usage, various specific game scenarios must be considered when using riichi, or facing [[defense|opponents who have called riichi]].
'''Riichi''' {{kana|立直}} or {{kana|リーチ}} is the most common [[List of yaku|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.


Unlike other yaku, the call for riichi operates at a player's discretion and is certainly not mandatory. Players may simply opt not to call riichi and retain the secrecy of a hand's tenpai status, using a tactic known as [[damaten]]. The decision for using riichi rests on some factors, primarily on need.  Current point standings often factor towards a riichi call, especially when falling behind in points.  On the other hand, point leaders may tend to be conservative to limit opportunities for other players [[ron|to score hands directly]].
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 ==
== 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 [[Scoring variations#Tobi|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.


When a player has a closed tenpai hand, the player may declare riichi.  Doing so gains the hand 1 han.  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.
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. Of course, a player must also have 1,000 points to begin with, assuming that a [[Rule_variations#Scoring|game ends with negative scores]].  Specific rulesets may handle differently what happens to the bet on a multiple win.
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, a notable exception may involve calls for [[kan]].
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 [[#Kan|certain circumstances]].


It is not allowed to declare riichi when less than four tiles remain in the wall. The player must be able to draw one more tile in an uninterrupted set of turns.  For any hand, the absolute last chance to call riichi is when the player has a chance to score riichi, [[haitei]], [[ippatsu]], and [[mentsumo]].
In addition to the 1 han from riichi itself, you can score further han through [[#Ippatsu|ippatsu]] and [[#Uradora|ura dora]].


===Noten riichi===
=== Kan ===
 
{{main|Kan#Kan during riichi}}
A player may actually declare riichi with a [[Tenpai|noten hand]].  This is a '''noten riichi''' {{kana|ノテン立直}}.  This type of play is highly not advisable.  If and when the hand results in [[ryuukyoku]], then it is required of the player to reveal the hand to show tenpai.  The noten riichi would naturally show noten; and it is subject to [[chombo]].  Likewise, chombo is applied if a win is called, as the hand's winning status would be verified only to reveal an invalid hand.  Of course, computer based play is usually programmed to prevent players from making such a riichi declaration.
 
=== Kan during riichi ===
{{main|Kan}}
 
When a riichi declarer holds three identical tiles and draws the fourth after the riichi announcement, he may form an [[Kan|ankan]] from these tiles instead of discarding the fourth. The hand composition and the possible winning tiles may not change: It is not allowed to declare kan if, for some possible winning tile, any of the three identical tiles may be interpreted as part of a shuntsu or part of the pair.
 
'''Example 1:'''
:{{#mjt:3444m778899s333z}} Illegal kan: {{#mjt:4m}} Legal kan: {{#mjt:3z}}.


It is not allowed to kan the fours. The manzu tiles may either be interpreted as a 3-4 [[Ryanmen|ryanmen]] wait and a 4-4 pair, or as a 4-man ankou with a 3-man [[tanki]] wait. A kan call would alter the wait just for a 3-man tanki.  For a legal kan declaration, the three identical tiles would have to be an ankou in any interpretation. Had the player drawn a west wind, he would have been allowed to kan it.
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.


'''Example 2:'''
There are two major rule variations on kan legality:
:{{#mjt:111m222333p5678s}} Legal kan: {{#mjt:1m}} {{#mjt:2p}} or {{#mjt:3p}}.
* 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.


In this example, none of the waits are affected by any of the kan possibilities.  The waiting tiles are completely unrelated to any of the existing triplets in this hand.  Therefore, it is acceptable to call kan during riichi here.
See [[Kan#Kan during riichi|Kan during riichi]] for more details.


=== Furiten ===
=== Furiten ===
{{main|Furiten}}
{{main|Furiten}}


During riichi, a player may be furiten. In this case, the riichi is considered to be a '''furiten riichi'''.  Likewise, after calling riichi, a player may decline the option to call on a winning tile, whether it be by self-draw or [[ron|by discard]].  However, if a win is declined, then the riichi declared hand is subject to furiten for the remainder of the hand.  Thus, all tiles discarded after the riichi declaration, as indicated by the discarded sideways tile, are considered to be guaranteed [[genbutsu|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.
During riichi, a player may be furiten. In this case, the riichi is considered to be a '''furiten riichi'''.


=== Ura dora ===
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 [[genbutsu|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.
[[Image:Uradora.png|250px|right|thumb|The benefits of uradora. [http://tenhou.net/0/?log=2014070812gm-0009-7447-daa26980&tw=3&ts=9]]]
{{main|Dora}}


When a riichi declarer wins, he may flip the tiles underneath the [[dora]] and kan dora indicators. These flipped ''ura dora indicators'' may increase the value of his hand.
=== Suucha riichi ===
{{main|Tochuu ryuukyoku}}


=== Tochuu ryuukoku ===
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.


{{main|Tochuu ryuukoku}}
===Noten riichi===


Tochuu ryuukoku, or abortive draw, is in effect when suucha riichi occurs. In this case, three riichis have been called; and a fourth one is called in place. If the discarded tile is not claimed for a win, then the hand ends.
In real life play, a player may declare riichi without tenpai - this would be a '''noten riichi''' {{kana|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.


=== Open riichi ===
== Scoring ==
'''Open riichi''' {{kana|オープン立直}} is an optional yaku, which is a modified version to riichi itself.  The principle works exactly in the same way as the original riichi.  However, there is an added bonus of 1-han attached, which is earned by revealing either the hand or the tile waits.  This naturally eases everyone else's ability to defend against the riichi.  As a further optional rule, yakuman may be awarded if any player actually [[ron|plays into]] the open riichi.  This is more or less a harsh penalty for playing into a revealed hand.  Many official organizations and tournaments do not implement open riichi.  It is more or less reserved for casual game or gambling setting.


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


=== Ippatsu ===
=== Ippatsu ===
{{main|Ippatsu}}
{{main|Ippatsu}}


'''Ippatsu''' {{kana|一発}} is a separate yaku but is very dependent on riichi. Riichi is required to score ippatsu, as the yaku is defined as a riichi winning before the declarer's next discard. [[Naki|Tile calls]], including [[kan]], are able to nullify ippatsu by denying it.
'''Ippatsu''' {{kana|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 [[Naki|tile calls]], including a player's own closed [[kan]], will invalidate ippatsu.
 
=== Uradora ===
[[Image:Uradora.png|250px|right|thumb|The benefits of uradora. [http://tenhou.net/0/?log=2014070812gm-0009-7447-daa26980&tw=3&ts=9]]]
{{main|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 ===
=== Double riichi ===
{{main|Double riichi}}
{{main|Double riichi}}


'''Double riichi''' {{kana|ダブルリーチ}} is a special case for riichi, where the player declares riichi on the first turn. No tile call may have interrupted the turn order before the declaration, where applicable.  For the [[dealer]], double riichi can never be interrupted. As the name implies, this yaku is worth 2 han instead of 1 han, as a bonus for the initial timing. With the added han value, a call for double riichi has a huge advantage over the other players in conjunction with the immediate speed and value compared to conventional riichi calls.
'''Double riichi''' {{kana|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''' {{kana|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 [[wait]]s (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 [[ron|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 ==
== Compatibility ==
{{main|Yaku compatibility}}
{{main|Yaku compatibility}}


{{yakuheader}}
{{Yaku compatibility table|RCH,DRI}}
| RCH ||bgcolor="000000"| ||bgcolor="000000"|  || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}}
|-
| DRI ||bgcolor="000000"| ||bgcolor="000000"|  || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}}
|}


Given the rules, riichi is compatible with all other yaku.  Likewise, riichi and double riichi cannot be combined as they are essentially the same yaku.  It just happens that double riichi is a specific instance of riichi.  Per rule and definition, it is impossible to attain ippatsu without riichi.
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 is dependent on the legality of the [[Riichi#Kan_during_riichi|kan call during riichi]]. With computer interfaces, this rule may be enforced by disabling a player's ability to call the kan during this situation.  However, with actual tiles, a player must be aware of this legality.  Otherwise, chombo may be enforced instead.
Once again, the prospect for [[rinshan kaihou]] to work with riichi depends on if you can [[Kan#Kan during riichi|kan during riichi]]. When playing with real tiles, a player must be aware of whether a kan is legal.


== Strategy ==
== Strategy ==
{{main|Riichi strategy}}
{{main|Riichi strategy}}


Calling riichi is an optional play.  Therefore, players often have to make various considerations, when it comes to using riichi. Often, this depends on the discarded tiles, how early or late in the hand, the hand value, and/or the player's hand composition. If possible, a player may opt not to use riichi at all and instead employ the strategy of [[damaten]].
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''' {{kana|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|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==
==External links==
{{jpwiki|立直}}
{{jpwiki|立直}}
* [http://osamuko.com/yaku-hai-riichi/ Yaku, Hai!: Riichi (& Ippatsu & Daburu Riichi)]
: [http://osamuko.com/ Osamuko] article on riichi.


[[Category:Yaku]]
[[Category:Yaku]]
[[Category:Game rules]]
[[Category:Game rules]]


{{Navbox strategy}}
{{Navbox yaku}}

Latest revision as of 01:51, 4 November 2024

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

Riichi in Japanese Wikipedia
Osamuko article on riichi.
Closed only Yaku - 1 han
Yaku - 1 han
Yaku - 2 han
Yaku - 3 han
Yaku - 6 han
Yakuman
Special
Optional
Topics
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