Keishiki tenpai: Difference between revisions

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'''Keishiki tenpai''' {{kana|形式聴牌}}, or '''shaped tenpai''', is otherwise known as a [[tenpai]] hand with no [[yaku]]. Some cases of tenpai also involve waiting for a so-called fifth tile, which is nonexistent.  Strategically, players often push for late tenpai hands regardless of yaku state for [[ryuukyoku]] to gain small points rather than lose them.
'''Keishiki tenpai''' {{kana|形式聴牌}}, also known as '''keitan''' or '''shaped tenpai''', is a [[tenpai]] hand with no [[yaku]]. Such a hand cannot win normally, but can still gain points from the tenpai settlements at an [[exhaustive draw]]. It can also win if it gains a conditional yaku (those being [[haitei]], [[houtei]], [[rinshan]], [[chankan]], or [[menzen tsumo]]), but the former four are rare, and menzen tsumo requires a closed hand.


==Abiguity==
==Strategy==
[[Image:Keishiki ankan.png|right|thumb|250px|Tenpai applied to an ankan case.]]
Usually, players do not aim for keikshiki tenpai until late into a hand, the third row of discards at the earliest.
The term is often confused with the "fifth tile" case.  Here, a hand waiting for a fourth tile that is simply hidden, discarded, or used by someone else remains a valid tenpai in all circumstances. A hand may contain a 1-2 [[Penchan|penchan]] and a previously declared [[Kan|kan]] of 3-3-3-3 in the same suit.  This renders the threes unavailable as winning tiles. Because of the prevalence of '''keishiki tenpai''', it is assumed that if the rule is different, it would be announced what qualifies as tenpai or not. As a precaution, it is almost always mentioned.


'''Example:'''<br>
While the point gain/loss from tenpai is relatively small, it can still matter, especially in close point races. There is also a small chance that [[haitei]] or [[houtei]] can allow a win. Therefore, if pushing for keitan is safe, then do so. However, players must be wary of other players already in tenpai, so [[defense]] considerations are important. It is better to lose points via noten than to deal into a big hand.
{{#mjt:12m444p678s1180z33m0z}}  Waiting for: {{#mjt:3m}}
 
===Quirks===
* On Ron2, there has been an instance of a person being able to call riichi with a gutshot wait shape for a 6-pin when they have made a closed kan of 6-pin already. The hand was considered noten, but did not trigger a chombo penalty (mainly due to programming assuming no one could do something that could be viewed as faulty). This conforms to the usual '''keishiki tenpai''' interpretation that the hand was not in a valid tenpai shape when it came to scoring a drawn hand, but not okay for determining if a player was legally allowed to declare [[riichi]].
* On Tenhou, there have been reports of a hand containing 12s44466688p with a kan of 3s, scored as in tenpai. This does not conform to the usual '''keishiki tenpai standard'''. Tenhou staff have confirmed that there was a decision to simplify interpreting if a hand was tenpai due to programming constraints. All hands that conform to '''keishiki tenpai''' are valid, as well as a few (such as the current case) that may not be.
 
==Strategy==
Players do not necessarily aim for keishiki tenpai until late into the hand.  Usually, consideration for such action begins on the third row of discards.  Ryuukyoku imposes point gains or losses. Even if minimal, players may find themselves motivated to be on the positive end of the exchange rather than the negative.  Plus, tenpai at ryuukyoku also provides a chance for either [[haitei]] or [[houtei]] to outright win the hand. Finally, players opting for this push for tenpai must also be wary of players already in tenpai, making [[defense]] considerations to be noted. With that said, it is preferable to lose points via noten rather than dealing into larger hands.


==Rule variation==
==Rule variation==
Some house rules factor keishiki tenpai into ryuukyoku, where hands even in tenpai may not receive tenpai payment.  Instead, the points for noten are deducted just because the hand lacks a yaku. However, this practice is generally uncommon.
Some house rules do not allow a keishiki tenpai to receive tenpai payment; the hand is treated as noten due to lacking a yaku. However, this practice is generally uncommon.


== External links ==
== External links ==
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[[Category:Game rules]]
[[Category:Game rules]]
[[Category:Terminology]]
[[Category:Terminology]]
{{jpwiki|形式聴牌}}

Latest revision as of 11:35, 19 August 2024

Keishiki tenpai 「形式聴牌」, also known as keitan or shaped tenpai, is a tenpai hand with no yaku. Such a hand cannot win normally, but can still gain points from the tenpai settlements at an exhaustive draw. It can also win if it gains a conditional yaku (those being haitei, houtei, rinshan, chankan, or menzen tsumo), but the former four are rare, and menzen tsumo requires a closed hand.

Strategy

Usually, players do not aim for keikshiki tenpai until late into a hand, the third row of discards at the earliest.

While the point gain/loss from tenpai is relatively small, it can still matter, especially in close point races. There is also a small chance that haitei or houtei can allow a win. Therefore, if pushing for keitan is safe, then do so. However, players must be wary of other players already in tenpai, so defense considerations are important. It is better to lose points via noten than to deal into a big hand.

Rule variation

Some house rules do not allow a keishiki tenpai to receive tenpai payment; the hand is treated as noten due to lacking a yaku. However, this practice is generally uncommon.

External links

Keishiki tenpai in Japanese Wikipedia
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