Tenhou and chiihou: Difference between revisions

Tenhou and chiihou
Type	Yakuman
Kanji	天和; 地和
English	Heavenly hand; Earthly hand
Value	Yakuman
Speed	Instant
Difficulty	Luck

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Latest revision as of 01:07, 10 August 2024

Tenhou 「天和」 is a yakuman obtained by the dealer completing the hand on the first tile draw. In other words, the hand wins before the first tile discard. Any combination of 14 tiles that can win can score tenhou. Declaring kan (or kita in sanma) will invalidate the yakuman.

Chiihou 「地和」 is similar to tenhou, except it is won by non-dealers winning on the first draw. In addition, any tile call made by any player will invalidate chiihou. By definition, both yakuman can only win by tsumo; ron is not allowed.

Formation

Tenhou and chiihou are entirely dependent on luck. The player only needs to recognize a complete hand and declare it. Failure to do so may result in a lost opportunity to score this rare yakuman.

One pitfall is to declare riichi, not recognizing that you had a winning hand.^[1] This is likely due to the temptation of calling double riichi before verifying the completeness of the hand. This puts the hand into furiten immediately for calling riichi on a winning tile. Therefore, it is necessary to check the hand before making such a dubious riichi call.

Value

Tenhou applies to dealer seats only, so therefore, it is always 48,000 points unless combined with another yakuman. Likewise, chiihou applies to non-dealers valued at 32,000 points. Both must be won via tsumo.

Renhou

Main article: Renhou

A related optional yaku is renhou. Assuming this yaku is used: if a player wins via ron before their first draw, and before any calls, then this yaku(man) is scored. Depending on rule variation, it may score as a mangan (or other value), not a yakuman.

Probability

A randomly drawn hand of 14 tiles has about a one in 330,000 (~0.0003%) chance of being a valid mahjong hand and thus qualifying for tenhou or chiihou.^[2] Based on a Monte Carlo simulation of one hundred billion (100,000,000,000) such randomly drawn hands, the distribution of outcomes is as follows:

Outcome	Occurences
Not a winning hand	99,999,696,816
Tenhou in standard form	267,813
Tenhou in chiitoitsu form	35,351
Tenhou with suuankou	43
Tenhou with kokushi musou	20
Tenhou with daisangen	1
Tenhou with chuuren poutou	1

References

External links

天和

Tenhou in Japanese Wikipedia

地和

Chiihou in Japanese Wikipedia

【天和】世界初！生放送対局にて炸裂！【役満】 (YouTube)

Tenhou scored at an RMU event.

天和国士無双十三面待ち

Tenhou combined with kokushi musou in the "Battle of Asura" mode of Mahjong Soul which allows players to exchange tiles before the hand starts. In this case, the game counts kokushi musou as the 13-way wait variant, combining with tenhou for a triple yakuman—144,000 points.

[1] ttp://www.osamuko.com/delicious-riichi-button-must-click-it/

[2] ttp://www10.plala.or.jp/rascalhp/mjmath.htm

[1]

[2]

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 * [http://tenhou.net/0/?log=2014031008gm-0029-0000-95234e4a&tw=2&ts=4 Sitting north]
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-'''Tenhou''' {{kana|天和}} is a [[List of yaku#Yakuman|yakuman]], which is attained by the dealer completing the hand on the first tile draw.  In this case, no tile has been discarded; and the hand is already declared a winner, before any other action had taken place.  By far, this is the fastest instance by which a player can win a hand.  The only [[naki|tile call]] that can interrupt this yakuman is a [[kan]] call made by the dealer.  Naturally, this would be a very dubious play on the dealer's part.
+'''Tenhou''' {{kana|天和}} is a [[List of yaku#Yakuman|yakuman]] obtained by the dealer completing the hand on the first tile draw. In other words, the hand wins before the first tile discard. Any combination of 14 tiles that can win can score tenhou. Declaring [[kan]] (or [[kita]] in [[sanma]]) will invalidate the yakuman.
-'''Chiihou''' {{kana|地和}} follows the same premise as tenhou, where the dealt hand is already tenpai and the initial tile draw results in a win.  The initial hand may use any pattern, as long as 13 tiles constitute a [[tenpai]] hand, and the 14th tile is the winning tile.  Unlike tenhou, chiihou applies to the non-dealers.  It can also be denied by any tile call made prior to the first draw.
+'''Chiihou''' {{kana|地和}} is similar to tenhou, except it is won by non-dealers winning on the first draw. In addition, any [[tile call]] made by any player will invalidate chiihou. By definition, both yakuman can only win by tsumo; [[ron]] is not allowed.
-Under normal circumstances for both yakuman, luck and recognition are the only factors contributing towards the hands' completion.  By definition, either yakuman are scored by tsumo, or drawing the winning tile.  It is impossible for either to win by [[ron|discard]].
 ==Formation==
-For both tenhou and chiihou hands, no action is required from the player, other than recognition of a complete hand with the 14 dealt tiles and the declaration of a winning hand.  Failure to do so may result in a lost opportunity to score this rare yakuman.
+Tenhou and chiihou are entirely dependent on luck. The player only needs to recognize a complete hand and declare it. Failure to do so may result in a lost opportunity to score this rare yakuman.
-Yet, unlike tenhou, chiihou may be interrupted by [[naki|tile]] calls prior to the tile draw; and hence the opportunity to score this yakuman.  If tile calls did occur prior to the draw, then the hand is limited to a [[mentsumo]] plus any other applied yaku and/or dora.
+One pitfall is to declare [[riichi]], not recognizing that you had a winning hand.<ref>http://www.osamuko.com/delicious-riichi-button-must-click-it/</ref>  This is likely due to the temptation of calling [[double riichi]] before verifying the completeness of the hand.  This puts the hand into [[furiten]] immediately for calling riichi on a winning tile.  Therefore, it is necessary to check the hand before making such a dubious riichi call.
-To even have the opportunity for either yakuman, it all rests on pure luck.  Player actions have no bearing on the composition of the [[start hand]].
+==Value==
+Tenhou applies to dealer seats only, so therefore, it is always 48,000 points unless combined with [[Multiple_yakuman|another yakuman]].  Likewise, chiihou applies to non-dealers valued at 32,000 points.  Both must be won via [[tsumo]].
-=== Double riichi furiten ===
-One pitfall of tenhou and chiihou may be the accidental call for [[riichi]] due to the failure of recognition.<ref>http://www.osamuko.com/delicious-riichi-button-must-click-it/</ref>  This is likely due to the temptation of calling [[double riichi]], before verifying the completeness of the hand.  This puts the hand into [[furiten]] immediately for calling riichi on a winning tile.  Therefore, it is necessary to check the hand before making such a dubious riichi call.
-==Value==
+==Renhou==
-Tenhou applies to dealer seats only, so therefore, it is always 48,000 points unless combined with [[Multiple_yakuman|another yakuman]].  Once again, chiihou applies to non-dealers valued at 32,000 points.  Both must be won via [[tsumo]].  The [[ron]] variety would be called [[renhou]], which has variable values and applications.
+{{Main|Renhou}}
+A related [[optional yaku]] is '''renhou'''. Assuming this yaku is used: if a player wins via ron before their first draw, and before any calls, then this yaku(man) is scored. Depending on rule variation, it may score as a [[mangan]] (or other value), not a yakuman.
 ==Probability==