Chankan: Difference between revisions

Chankan
Type	Yaku
Kanji	搶槓
English	Robbing a kan
Value	1 han
Speed	Dependent
Difficulty	Very hard

VisualWikitext

Latest revision as of 20:51, 28 March 2024

Chankan 「搶槓」 is a standard yaku dependent on an opponent's kan. When an opponent calls to upgrade a minkou (triple called via pon) to a shominkan (added kan), a player in tenpai for that tile may call ron, gaining the yaku of chankan.

Development

Chankan example, where the player declared ron on 1-pin and all four are shown as a kan.

Known in English as "robbing a kan", chankan occurs when a player is in tenpai for a tile used to upgrade a pon into an added kan. Any tenpai hand works for chankan, even if the hand is otherwise yakuless. The other two types of kan cannot normally be used for this yaku.

In almost all cases, players cannot ron off an ankan (closed kan). The notable exception is with a kokushi tenpai hand. For kokushi, the last tile needed for the yakuman may be won from an opponent's ankan. However, in some rules, kokushi cannot win in this way.
It is impossible to ron off an daiminkan (open kan). When a tile is discarded, it can either be used for ron, or it can be used to complete the kan. Ron takes precedence over kan, so the player wins before the kan is made. If the ron call is skipped, you cannot retroactively ron after the kan is made.

In other words, an opponent must call pon before your hand wins, then draw the fourth copy of that tile, then call the added kan. An opponent must have all four copies of a tile in their hand to call added kan. Therefore, chankan becomes impossible if you are holding any copy of that tile (because then the opponent cannot gain that tile for their kan).

Chankan interrupts the call for kan before it starts. This means that kandora are not revealed after chankan, and chankan denies the opponent's rinshan draw.

Machi

Main article: Machi

As mentioned above, in order to obtain chankan, it is impossible to have a copy of the given winning tile in your hand. Therefore, waits involving shanpon or tanki are impossible. If you hold a tile in your hand, the opponent cannot make an added kan, making it impossible to chankan with that tile.

So, when it comes to machi (wait patterns), only three basic types can be used: penchan, kanchan, and ryanmen. These are all waits to complete a sequence.

In the case for kokushi musou, the hand is tenpai for kokushi with one of the 13-tile types already paired, and it is waiting for the last tile type for completion. Depending on the rules, kokushi may or may not be allowed to win from a closed kan.

Furiten

Chankan can only happen when a player calls pon. Therefore, there is at least one player who will be in furiten for chankan, and that is the player who was used to complete the original pon call.

Limitation

When a player is in tenpai for suukantsu, some rule variations allow invoking a fifth kan to cause a draw. If a fifth kan is allowed in this way, chankan may not apply - the game ends before a chankan can happen.

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
CHK

Excluding kokushi musou, chankan requires at least one sequence, because waits to complete a pair (tanki) or triplet (shanpon) would be impossible. This excludes toitoi, chiitoitsu, and honroutou. Ryanpeikou is also not allowed, due to the tile requirement. A ryanpeikou tenpai would require at least one copy of the winning tile, which prevents the other players from calling kan.

As for rinshan, haitei, houtei, and mentsumo, it is physically impossible to combine any of these four with chankan. Rinshan, mentsumo, and haitei require a win by self draw, while chankan is always won with ron. In the case of houtei, a player is not allowed to call kan if there are no tiles left in the live wall, so a chankan cannot be the last discard.

Ippatsu

The ippatsu yaku is normally interrupted by a kan call. To call chankan, the opposing player had already called for kan. However, ippatsu is still not interrupted because the whole kan process has not been completed. The entire kan process includes the kan call itself, plus the rinshan draw and the discard afterwards. The chankan win occurs in the middle of that process. So, it is allowable to score both ippatsu and chankan at the same time.

Double Riichi

Chankan requires an added kan, which itself requires a pon. This invalidates double riichi for any regular hand:

If a pon is made before the riichi call, 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. Since chankan can only be won off ron, furiten makes this yaku impossible.

However, an exception exists with kokushi musou. Depending on rule variation, kokushi may be won off a 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, neither double riichi or chankan would actually be scored.

Kokushi musou variation

If the rules allow, a special case for kokushi musou exists. When a kokushi hand is in tenpai, it may win if an opponent calls a closed kan for the tile you are winning for. Thus, ron may be declared, invoking this special rule. This is the only case where a tile may be taken from an closed kan.

However, this particular rule may be subject to variation, which may or may not allow this play to occur.

External links

搶槓

Chankan in Japanese Wikipedia

@@ Line 7: / Line 7: @@
 |difficulty  = Very hard
 |yakuCombine = All standard yaku, except [[mentsumo|tsumo]], [[rinshan kaihou|rinshan]], [[haitei]], and [[houtei]]
-|gameExample = * [http://tenhou.net/0/?log=2012110214gm-0009-7447-908b0b9a&tw=0&ts=6 Chankan nomi]
+|gameExample = * [http://tenhou.net/0/?log=2012112813gm-0009-7447-af4e435f&tw=2&ts=8 Chankan with] [[Ippatsu]]
-* [http://tenhou.net/0/?log=2012112813gm-0009-7447-af4e435f&tw=1&ts=8 Chankan with] [[Ippatsu]]
+* [http://tenhou.net/0/?log=2014032411gm-0089-0000-893e2d65&tw=1&ts=9 Chankan declined]
+* [http://tenhou.net/0/?log=2015032605gm-0089-0000-70f97ed2&tw=0 Chankan baiman]
 }}
-'''Chankan''' (搶槓) is a standard yaku.  It is dependent on the usage of [[kan]], where a player may declare ron while a player calls to upgrade a [[koutsu|minkou]] to a [[Kan#Shominkan|shominkan]].  In other words, if a player is tenpai for a tile used for an "added kan", then the player may declare a win on that tile.  In most cases you are not allowed to call ron on an [[Kan#Ankan|ankan]]. The exception to this is when you are in [[kokushi]] [[tenpai]] and another player's ankan is your wait.
+'''Chankan''' {{kana|搶槓}} is a standard yaku dependent on an opponent's [[kan]]. When an opponent calls to upgrade a [[koutsu|minkou]] (triple called via [[pon]]) to a [[Kan#Shominkan|shominkan]] (added kan), a player in tenpai for that tile may call ron, gaining the yaku of chankan.
-==Hand pattern==
+==Development==
-[[image:Chankan.png|250px|thumb|Chankan example, where the player declared ron on {{#mjt:1p}} and all four are shown as a kan.]]
+[[image:Chankan.png|250px|thumb|[http://tenhou.net/0/?log=2012112813gm-0009-7447-af4e435f&tw=2&ts=8 Chankan example], where the player declared ron on 1-pin and all four are shown as a kan.]]
+Known in English as "robbing a kan", chankan occurs when a player is in [[tenpai]] for a tile used to upgrade a [[pon]] into an added [[kan]]. Any tenpai hand works for chankan, even if the hand is otherwise yakuless. The other two types of kan cannot normally be used for this yaku.
-Alternatively, this yaku may be referred to as "robbing a kan".
+*In almost all cases, players cannot ron off an [[ankan]] (closed kan). The notable exception is with a [[kokushi]] [[tenpai]] hand. For kokushi, the last tile needed for the yakuman may be won from an opponent's ankan. However, in [[Rule_variations#Kokushi_and_chankan|some rules]], kokushi cannot win in this way.
+*It is impossible to ron off an [[Kan#Daiminkan|daiminkan]] (open kan). When a tile is discarded, it can either be used for ron, or it can be used to complete the kan. Ron takes precedence over kan, so the player wins before the kan is made. If the ron call is skipped, you cannot retroactively ron after the kan is made.
-==Machi==
+In other words, an opponent must call [[pon]] before your hand wins, then draw the fourth copy of that tile, then call the added kan. An opponent must have all four copies of a tile in their hand to call added kan. Therefore, chankan becomes impossible if you are holding any copy of that tile (because then the opponent cannot gain that tile for their kan).
+Chankan interrupts the call for kan before it starts. This means that [[kandora]] are not revealed after chankan, and chankan denies the opponent's [[rinshan]] draw.
+===Machi===
 {{main|Machi}}
+As mentioned above, in order to obtain chankan, it is impossible to have a copy of the given winning tile in your hand. Therefore, waits involving [[shanpon]] or [[tanki]] are impossible. If you hold a tile in your hand, the opponent cannot make an added kan, making it impossible to chankan with that tile.
+So, when it comes to [[machi]] (wait patterns), only three basic types can be used: [[penchan]], [[kanchan]], and [[ryanmen]]. These are all waits to complete a [[shuntsu|sequence]].
+In the case for [[kokushi musou]], the hand is tenpai for kokushi with one of the 13-tile types already paired, and it is waiting for the last tile type for completion. Depending on the rules, kokushi may or may not be allowed to win from a closed kan.
+===Furiten===
+Chankan can only happen when a player calls pon. Therefore, there is at least one player who will be in [[furiten]] for chankan, and that is the player who was used to complete the original pon call.
+===Limitation===
+When a player is in tenpai for [[suukantsu]], some [[rule variations]] allow invoking a fifth kan to cause a draw. If a fifth kan is allowed in this way, chankan may not apply - the game ends before a chankan can happen.
+== Compatibility ==
+{{main|Yaku compatibility}}
+{{Yaku compatibility table|CHK}}
-As defined, chankan can only be achieved when a [[minkou]] (open triplet) is upgraded to a ''shouminkan''.  In other words, another player had called pon earlier and then drew the 4th tile, to be called kan with.  If a player is tenpai for that tile, then the player may declare ron.
+Excluding kokushi musou, chankan requires at least one sequence, because waits to complete a pair (tanki) or triplet (shanpon) would be impossible. This excludes [[toitoi]], [[chiitoitsu]], and [[honroutou]]. [[Ryanpeikou]] is also not allowed, due to the tile requirement. A ryanpeikou tenpai would require at least one copy of the winning tile, which prevents the other players from calling kan.
-So, when it comes to [[machi]] (wait patterns), only three basic types can be used for chankan: [[penchan]], [[kanchan]], and [[ryanmen]].  Some patterns that utilize any of these three may also apply.  This is simply due to the number of tiles remaining (just one), for every minkou.
+As for [[rinshan]], [[haitei]], [[houtei]], and [[mentsumo]], it is physically impossible to combine any of these four with chankan. Rinshan, mentsumo, and haitei require a win by self draw, while chankan is always won with ron. In the case of houtei, a player is not allowed to call kan if there are no tiles left in the live wall, so a chankan cannot be the last discard.
-In the case for [[kokushi musou]], the hand is tenpai for kokushi with one of the 13-tile types already paired; and it is waiting for the last tile type for completion.  An exception to kan calls involving [[ankan]] (closed kan) is made.
+=== Ippatsu ===
+The [[ippatsu]] yaku is normally interrupted by a kan call. To call chankan, the opposing player had already called for kan.  However, ippatsu is still not interrupted because the whole kan process has not been completed.  The entire kan process includes the kan call itself, plus the rinshan draw and the discard afterwards.  The chankan win occurs in the middle of that process.  So, it is allowable to score both ippatsu and chankan at the same time.
-== Compatability ==
+=== Double Riichi ===
-{{main|Yaku compatability}}
+Chankan requires an added kan, which itself requires a pon. This invalidates double riichi for any regular hand:
-{{yakuheader}}
+* If a pon is made before the riichi call, double riichi is negated.
-| CHK || {{yes}} || {{yes}} || {{yes}} || {{no}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{no}} || {{yes}} || {{yes}} || {{yes}} || {{yes}} || {{no}} || {{yes}} || {{no}} || {{yes}} || {{yes}} || {{no}} || {{no}} || {{no}} || {{no}} || bgcolor="000000"|
+* If the pon call happens after the riichi call, then the double riichi player must have declined their winning tile, invoking [[furiten]]. Since chankan can only be won off ron, furiten makes this yaku impossible.
-|}
-Essentially, chankan combines that utilizes the [[machi|tile waits]] of either [[ryanmen]] or [[kanchan]].  That excludes [[toitoi]], [[chiitoitsu]], and [[honroutou]].  These three require the tile waits of either [[shanpon]] or [[tanki]]; and so, the fourth tile to invoke kan is used in another player's hand.  As for [[ryanpeikou]], this hand may use ryanmen for completion.  However, the tile requirement for ryanpeikou is already in the hand.  Otherwise, chankan invoked with a ryanpeikou tenpai hand would only count for [[iipeikou]].
+However, an exception exists with [[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, neither double riichi or chankan would actually be scored.
-As for [[rinshan]], [[haitei]], [[houtei]], and [[mentsumo]], it is physicially impossible to combine any of these four with chankan.  In the case for rinshan, the possibility to combine with chankan is outright impossible, as rinshan is defined by winning from the dead wall tile draw.  In the case of haitei and houtei, a player cannot call kan, when the dead wall cannot be maintained at 14-tiles.  This case occurs, at the last allowable tile draw of the hand.
+== Kokushi musou variation ==
+[[Image:Kokushi deny.png|thumb|right|250px|Case where a [[kan|closed kan]] was declared during a [http://tenhou.net/0/?log=2018041311gm-000b-7447-e286a4e6&tw=2&ts=6 kokushi tenpai].]]
+If the rules allow, a special case for [[kokushi musou]] exists. When a kokushi hand is in tenpai, it may win if an opponent calls a closed kan for the tile you are winning for. Thus, ron may be declared, invoking this special rule. This is the only case where a tile may be taken from an closed kan.
-=== Kokushi musou ===
+However, this particular rule may be [[Yaku_variations#Kokushi_and_chankan|subject to variation]], which may or may not allow this play to occur.
-[[Image:Kokushi Denied.png|thumb|right|250px|Case where a [[kan|closed kan]] was declared during a [http://tenhou.net/0/?log=2013121107gm-0019-0000-b01e54cd&tw=1&ts=7 kokushi tenpai].]]
-Chankan may work with [[kokushi musou]], especially when a player upgrades a [[minkou]] to a [[kan|shouminkan]] (added kan to an open pon).  Furthermore, a kokushi tenpai hand may be awarded a win if another player calls an [[kan|ankan]] (closed kan) with that particular winning tile.  Thus, ron may be declared in that instance.  This is the only case where a tile may be taken from an closed kan.  However, this particular rule may be subject to variation, which may or may not allow the play to occur.
 ==External links==