Japanese Mahjong Wiki

Riichi: Difference between revisions

Page Discussion

Riichi (view source)

Revision as of 21:00, 24 March 2024

3,091 bytes removed ,  24 March
m
→‎Open riichi: clarify: the yakuman rule is unrelated to "most professional games don't allow open riichi"
VisualWikitext
m (→‎Open riichi: clarify: the yakuman rule is unrelated to "most professional games don't allow open riichi")
(47 intermediate revisions by 7 users not shown)
Line 14: Line 14:
}}
}}


'''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 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, occurring in ≥40% of winning wands across various platforms and professional settings. Any closed hand that is in [[tenpai]] can choose to declare riichi, gaining this yaku.


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 game scenarios 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.
* If the [[Rule_variations#Scoring|game ends when a player has a negative score]], the player must have at least 1,000 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 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]].  Of course, computer based play is usually programmed to prevent players from making such a riichi declaration.
Kan during riichi is a discretionary play. Players must take note of the hand composition to determine whether the kan is allowable or not. If the call alters the hand's waiting pattern or alters the hand's composition, kan is not allowed. Improper calls are subject to chombo if detected.


=== Kan during riichi ===
=== Furiten ===
{{main|Kan}}
{{main|Furiten}}


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


Example 1:
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.
:{{#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.
=== Suucha riichi ===
{{main|Tochuu ryuukyoku}}


Example 2:
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.
:{{#mjt:111m222333p5678s}} Legal kan: {{#mjt:1m}} {{#mjt:2p}} or {{#mjt:3p}}.


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.
===Noten riichi===


=== Furiten ===
In real life play, a player may declare riichi without tenpai - this would be a '''noten riichi''' {{kana|ノテン立直}}, 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 computer based play will prevent players from declaring a riichi without tenpai.
{{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.
== Scoring ==


=== Ura dora ===
Two yaku are specifically associated with riichi: '''ippatsu''' and '''double riichi'''. In addition, '''ura dora''' may be scored for any winning riichi hand.
[[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.
=== Ippatsu ===
{{main|Ippatsu}}


=== Tochuu ryuukoku ===
'''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.


{{main|Tochuu ryuukoku}}
=== 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}}


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.
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.


== Riichi based yaku ==
=== Double riichi ===
Two yaku are specifically associated with riichi: '''ippatsu''' and '''double riichi'''.
{{main|Double riichi}}


=== Ippatsu ===
'''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.
{{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.
=== 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. 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.


=== Double riichi ===
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.
{{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.
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}}
|-
| IPP || {{yes}} || {{yes}} ||bgcolor="000000"|  || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{no}} || {{yes}} || {{no}} || {{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.
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.
Line 92: Line 90:
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 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.


== Strategy ==
=== Double riichi ===
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]].
Double riichi has the same compatibility as riichi, except for [[chankan]]. This is because, for a regular hand, chankan may only be formed from an [[Kan#Shouminkan|added kan]], which itself requires a call for [[pon]] to happen first.
   
* If the pon call happens before the riichi call, then double riichi is negated.
* If the pon call happens after the riichi call, then the double riichi player must have declined their winning tile, invoking [[furiten]]. Chankan can only be won from [[ron]], so furiten prevents chankan entirely.


=== Advantages ===
An exception is the yakuman [[kokushi musou]]. Depending on [[Kokushi_musou#Chankan_rule_variation|rule variation]], kokushi may be won off a [[ankan|closed kan]], which does not require a previous pon call. Therefore, in order to win with double riichi + chankan, it must also have kokushi. Since this would be a yakuman hand, the yaku of "chankan" is never actually scored.


* Any closed hand becomes eligible for winning by ron.
== Strategy ==
* Riichi is an automatic yaku and is eligible to count for 1 additional han (after a win).
{{main|Riichi strategy}}
* Access to the [[dora|ura-dora]] (after a win).
* Kans formed by any player provide two extra dora indicators for the riichi declarer instead of one.
* Other players are recommended to defend against riichi calls, if possible or needed.  Otherwise, players run the risk of falling to that hand.
 
=== Disadvantages ===
 
* It is less likely for opponents to deal in.
* By rule, the hand is locked.  Therefore, it is impossible to change the composition of the hand in order to get a better wait or an improved score.
* Likewise, a player can no longer defend and instead wait for a winning tile.
* Other players still have the option to develop their hands and potentially "snipe" the hand.  [http://tenhou.net/0/?log=2012111209gm-0009-7447-x33034e7e5279&tw=2&ts=4 Example].
* It is highly recommended to declare the win on the first instance of a winning tile, even if the tile is a [[yasume]] or a lower scoring tile (based on yaku).  Otherwise, the hand is subject to [[furiten]].  A riichi call disables a person's ability to be [[targeting|selective]] of points from particular players (if need be).
 
=== Miscellaneous considerations ===


Once again, riichi is a discretionary play.  In fact, in all instances of considering and calling riichi, risk is involved.  Therefore, various factors must be considered before employing using riichi.  At the same time, many plays involving riichi are highly recommended.  Employing riichi is a matter of the current game state.  Now, here are some questions to consider:
Calling riichi is an optional play.  Therefore, players often have to make various considerations when it comes to using riichi.  Often, this will depend 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]].
 
<!-- Feel free to provide answers with a preceding : below each question -->
<!-- Likewise, feel free to add some questions for consideration -->
* '''What game round is it?'''
* '''Is the lead currently held?'''
* '''Overall, what is the current point standing?'''
::[http://tenhou.net/0/?log=2014092217gm-0089-0000-3fd71626&tw=3&ts=8 Answer 1]
::Point standing have great influence over whether to call riichi or not.  In this example, it was completely unnecessary.
* '''Is it necessary to improve the hand by calling riichi?'''
* '''Would [[damaten]] be sufficient?'''
::[http://tenhou.net/0/?log=2014081313gm-0089-0000-16dea257&tw=1 Answer]
::For the first two hands, riichi was not called as the hands were valued enough without the riichi call.  A call for riichi in either example produces minimal gain for the risk of riichi.
* '''Can the hand be improved by drawing particular tiles?'''
* '''How many tiles are available for winning?'''
* '''Is it safe to discard the extra tile, to call riichi?'''
* '''Did anyone else call riichi previously?'''
* '''How many tile draws are left?'''
* '''Does the hand require riichi to end the game, while in the preferred position (1st - 3rd)?'''
::[http://tenhou.net/0/?log=2014081513gm-0089-0000-aba022ec&tw=3 Answer]
::Riichi was called here, as the hand is able to end the game by sending a player into negative.  Yet, the position of 2nd is retained.


=== Oikake riichi ===
=== Oikake riichi ===
For any given hand, more than one player may call riichi.  Subsequent riichi calls after the first is called '''oikake riichi''' {{kana|追いかけリーチ}}, or "chasing riichi". Oikake has one distinct advantage of an ippatsu ron chance against any previous riichi hands before taking a draw.  After all, defense is no longer a factor to those hands, as they are committed to discarding non-winning tiles.  The hands are essentially engaged in a "riichi duel" provided that they have different waiting tiles. Under many rulesets, the hand aborts in the event for all players to have declared riichi via [[suucha riichi]].


'''Oikake riichi''' {{kana|追いかけリーチ}} is a declared riichi, after another player had already declared riichi.  In this state, two or even three players have simultaneously declared riichi; and thus, the game becomes a contest between two or three tenpai hands.  In this state, any riichi declarer is liable of playing into another's riichi call.  At the time same, this type of riichi is often utilized because at least one player is not able to defend.  With multiple riichis occurring simultaneously, the players end up in a "riichi duel".
=== Karaten riichi ===
 
Riichi may actually be called if all waiting tiles are rendered unavailable.  A hand in this state is rendered as [[karaten]].  In this state, the hand is not winnable as the number of available winning tiles is zero.  Such calls may be made by mistake, or intentionally invoked to cause players to defend.
The process of four active riichi hands is not possible due to ''[[Tochuu ryuukoku|suucha riichi]]'', or four called riichi.  In this case, the hand ends if the fourth riichi discard is not a winning tile for any of the previous three.


==External links==
==External links==
{{jpwiki|立直}}
{{jpwiki|立直}}
* [http://justanotherjapanesemahjongblog.blogspot.com/p/riichi-theory.html Theories on Riichi]
* [http://osamuko.com/yaku-hai-riichi/ Yaku, Hai!: Riichi (& Ippatsu & Daburu Riichi)]
: [http://osamuko.com/ Osamuko] article on riichi.


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


{{Navbox yaku}}
{{Navbox yaku}}
{{Navbox strategy}}
Hordes
1,727

edits

Retrieved from "https://riichi.wiki/Special:MobileDiff/11840...24337"