Kan: Difference between revisions

'''Kan''' {{kana|カン}} is a special [[naki|tile call]]. This call forms a [[mentsu|tile grouping]] of four identical tiles, called '''kantsu''' {{kana|槓子}}. Just like all tile calls, it is optional.

While it appears as a four-of-a-kind, the tiles used for the kantsu actually function as a [[koutsu|three-of-a-kind]] plus one extra tile. Therefore, the set counts towards the [[Yaku#Triplet|triplet-based yaku]], such as [[toitoi]] and [[sanankou]]. After declaring kan, the player is required to take an extra tile draw from the [[dead wall]]. This drawn tile is called the '''[[rinshanpai]]''', or '''dead wall draw'''.  After the kan call and player's discard, then another [[dora|dora indicator]] is revealed.

The main benefits of kan are the revealed kan dora, a draw from the dead wall, and somewhat increased [[fu]] count. However, any of your opponents can also benefit from kan dora, so kan is inherently risky. Therefore, you should [[kan strategy|assess the situation]] before you make a kan.

Like the other tile calls, kan is also a tile call. However, it comes with special properties and rules. These rules apply when a player possesses or gains possession of four of the same tile; and then the player makes the kan call.

# The four identical tiles are shown and are set aside, like an open call. Together, the four tiles now count as one [[Mentsu|tile group]].

A special case may involve the yaku, [[chankan]]. If the kan call involves a shouminkan and the added tile is a winning tile for another player, then chankan may be applied upon the declaration of another player's winning hand. In this case, the hand ends before the player even gets to draw the extra tile from the dead wall. Thus, the process of calling kan gets interrupted in favor of another player's winning hand.

The call for kan reveals additional dora in the form of [[dora|kandora]]. The timing of this reveal is variable, depending on [[Dora variations|the rule set and/or game platform]].   

*The simplest rule is to immediately reveal dora after kan. This rule would place to kan reveal right after step 2.

*Many platforms distinguish between open and closed kans. In these rules, closed kans will reveal the kan dora immediately. Open kans will only reveal kan dora after discarding, or after making another kan (i.e. after either step 6 or 7).  

 

Regarding the timing of the kandora, players will need to consult organizational, tournament, and/or local rules.

*Closed triplet with the fourth tile type discarded (Daminkan; open kan)

*Open triplet with the fourth tile type drawn (Shouminkan; added kan)

*All four tile types drawn (Ankan; closed kan)

Some rules invoke [[Sekinin barai#Sekinin barai for rinshan kaihou|sekinin barai]] on a player discarding into the daiminkan.

Also known as a "closed kan", a player may draw all four of a tile type.  Unlike the other two kan types, '''ankan''' {{kana|暗槓}} keeps the hand closed, unless the hand has been opened previously.  Thus, even with an ankan call, the player may still have the option of declaring [[riichi]] even with such a kan call, calling kan during riichi barring restrictions, and/or winning the hand via [[mentsumo]].

Like a shominkan, an ankan may be declared during the player's turn.  As such, the player holds all four tiles. The same restrictions as for the shominkan apply.  An ankan may not be subject to chankan, except against a [[kokushi]] [[tenpai]], if the rules allow.

If in possession with the proper tiles, a player may call kan more than once consecutively.  Theoretically, up to 4 kan calls can be made in one turn.

As for kan dora, this once again depends on the ruleset.

*If a kan dora would be immediately revealed, such as for closed kan, the kan dora is revealed on making the kan.

*If a kan dora would be delayed, such as for an open kan or added kan, a kan dora is revealed after a discard or after the next subsequent kan call.

 

In the case of the above example, two added kans were called sequentially, but only one kan dora indicator was shown upon winning the hand.

A player may be allowed to call a closed kan during riichi, depending on the hand's composition.

 

Under most professional rulesets, a player is not allowed to call kan if it would change the hand's possible winning tiles, or if it would change any possible interpretation of the hand. If, for any winning tile, any of the three identical tiles can be interpreted as part of a [[shuntsu|sequence]] or part of the pair, the kan is not allowed.

Under some rulesets, such as in [[tenhou.net]] and [[Mahjong Soul]], an alternative is used: so long as a kan does not change the hand's possible winning tiles, the kan is allowed. (I.e., changing the hand interpretation is allowed.)

Of course, even if a kan is allowed, players may choose to decline a kan call. While a player can benefit from kan dora (and kan uradora), so will their opponents.

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. Overall, the hand waits for 2-5-3 man. A kan call would invalidate the 3-4 ryanmen, turning the hand into just a 3-man tanki. Thus, it is forbidden. It is allowed to kan the west winds, since they would be considered an ankou no matter which tile is won.

:{{#mjt:3335666p111456s}} Potentially illegal kan: {{#mjt:3p}} Illegal kan: {{#mjt:6p}}  

 

A kan on the 3p would not change the waits. However, if the hand was won with 4p, the hand could be interpreted as:

In this case, the 3p does not form a [[koutsu|triplet]], but rather a pair and a part of a sequence. A kan on the 3p would remove this potential interpretation of the hand, and therefore may be forbidden (depending on ruleset).

:{{#mjt:222333444p23m11z}} Potentially illegal kan: {{#mjt:2p}} {{#mjt:3p}} or {{#mjt:4p}}

In this case, a kan call on any of the pinzus would leave only the three triplets interpretation possible. Thus, any of these kan would be deemed illegal after riichi (depending on ruleset).

This is an "abortive draw" regarding kan calls.  From the dead wall, only four tiles can be used for the extra draw, or '''rinshanpai'''.  The remaining tiles from the dead wall are used as dora indicators, or they are tile replacements from the regular wall.  Neither of these two tile type can be used in play.  As a result, the limit of kan calls for a hand session is set to four.  After the fourth kan call, the [[hanchan|kyoku]] (hand session) ends after the [[rinshan]] draw and subsequent discard.   

However, an exception is made for players with [[suukantsu]] tenpai.  After the fourth kan call, the game continues, giving the player a chance to score the yakuman. Under many rulesets, the other players are not allowed to call a fifth kan to invoke the abortive draw. Some [[rule variations]] may allow a fifth kan to immediately end the game in a draw, though.<ref>https://youtu.be/eds4GAKPlOc?t=5m7s</ref> If this rule variation is used, the fifth-kan draw happens before [[chankan]] and [[rinshan]] can happen.

The nature of [[dora|kan dora]] makes the call for kan inherently risky.  With this in mind, some quick assessment is needed before making such a call.