Toitoihou: Difference between revisions

Toitoihou
Type	Yaku
Kanji	対々和; 対々
English	All triplets
Value	2 han
Speed	Medium
Difficulty	Easy

VisualWikitext

Latest revision as of 05:06, 23 November 2024

Toitoihou 「対々和」, often shortened to toitoi 「対々」, is a yaku scored when all four tile groups are triplets (and/or kans), giving it the English name of "All Triplets".

Tile pattern

Agari:

or

Agari:

or

Closed toitoi

Ron:

or

If this hand wins by tsumo, then it counts for the suuankou yakuman. Otherwise, it's a toitoi mixed with sanankou.

Formation

As the name implies, this yaku requires koutsu. Usually, this yaku is called open due to the ability for pon to claim discarded tiles from any player, giving this yaku the nickname of "pon palace". This yaku does not reduce in value once opened.

Viability

Naturally, this yaku is reasonable to go for with many triplets and/or pairs. However, toitoi often looks easier than it actually is. There are only 2 tiles that can convert a pair into a triplet;^[1] there are 8 tiles that can convert a ryanmen into a sequence. While pon can turn pairs into triplets, the tiles needed to pon may not be discarded. The 2 tiles could be in the dead wall, or used in an opponent's hand.

Pairs made out of middle tiles (tiles from 3-7) are particularly hard to pon, because middle tiles are generally more likely to be kept in an opponent's hand. When there are multiple pairs made out of middle tiles, this yaku becomes slower to complete. In addition, a hand with many pairs can also form chiitoitsu.

If the hand can score another yaku, such as tanyao or yakuhai, toitoi becomes more viable. Say you had a tanyao hand with the potential for toitoi. If a sequence forms, you can go for a normal tanyao win. If you get lucky, and many triplets form, you can score toitoi as a bonus.

Versus chiitoitsu

Some (rough) rules of thumb between toitoi and chiitoitsu are:

With 4 pairs and one turns into a sequence or triplet, it is often best to go for the regular hand structure. This may or may not be toitoi. Exception: if the hand is entirely disconnected except for the single sequence/group, then go chiitoitsu.
With 5 pairs, chiitoitsu is preferred.
- With 4 pairs + 1 triplet, keep your options open for both chiitoitsu and toitoi. With 4 pairs, 1 triplet, and 2 lone tiles, the hand can turn into chiitoi by drawing one of the lone tiles (discarding the triplet), or toitoi by pon. In this scenario, if you can pon one of the pairs, do so and aim for toitoi.
With 4-5 pairs, and one of the pairs cannot be turned into a triplet, because both remaining tiles of the pair are visible, then favor chiitoitsu over toitoi.

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
TOI

Toitoi is incompatible with any yaku requiring a sequence, meaning pinfu, iipeikou, ittsu, sanshoku doujun, ryanpeikou, and chankan (since it can only win on a sequence wait). It also cannot be combined with chiitoitsu, since it doesn't use mentsu.

Toitoi with mentsumo and junchan actually form yakuman, as suuankou and chinroutou respectively. Toitoi with chanta forms honroutou instead.

Notes

↑ 4 copies of each tile, -2 in hand, leaving 2 left in the wall to pon

External links

対々

Toitoihou in Japanese Wikipedia

[1] 4 copies of each tile, -2 in hand, leaving 2 left in the wall to pon

[1]

@@ Line 27: / Line 27: @@
 Naturally, this yaku is reasonable to go for with many triplets and/or pairs. However, toitoi often looks easier than it actually is. There are only 2 tiles that can convert a pair into a triplet;<ref>4 copies of each tile, -2 in hand, leaving 2 left in the wall to pon</ref> there are 8 tiles that can convert a [[ryanmen]] into a sequence. While pon can turn pairs into triplets, the tiles needed to pon may not be discarded. The 2 tiles could be in the [[dead wall]], or used in an opponent's hand.
 Pairs made out of middle tiles (tiles from 3-7) are particularly hard to pon, because middle tiles are generally more likely to be kept in an opponent's hand. When there are multiple pairs made out of middle tiles, this yaku becomes slower to complete. In addition, a hand with many pairs can also form [[chiitoitsu]].
-Some (rough) rules of thumb between toitoi and chitoitsu are:
+If the hand can score another yaku, such as [[tanyao]] or [[yakuhai]], toitoi becomes more viable. Say you had a tanyao hand with the potential for toitoi. If a sequence forms, you can go for a normal tanyao win. If you get lucky, and many triplets form, you can score toitoi as a bonus.
+=== Versus chiitoitsu ===
+Some (rough) rules of thumb between toitoi and chiitoitsu are:
 *With 4 pairs and one turns into a sequence or triplet, it is often best to go for the regular hand structure. This may or may not be toitoi. Exception: if the hand is entirely disconnected except for the single sequence/group, then go chiitoitsu.
-*With 5 pairs, chiitoitsu is preferred. Keeping the option for toitoi is fine (e.g. 4 pairs, 1 triplet, 2 lone tiles. The hand can turn into chiitoi if you discard the triplet, can toitoi if you pon) so long as the pairs are reasonable to pon.
+* With 5 pairs, chiitoitsu is preferred.
-*With 4-5 pairs, and one of the pairs cannot be turned into a triplet, because both remaining tiles of the pair are [[Kabe#Visible TIles|visible]], then favor chiitoitsu over toitoi.
+** With 4 pairs + 1 triplet, keep your options open for both chiitoitsu and toitoi. With 4 pairs, 1 triplet, and 2 lone tiles, the hand can turn into chiitoi by drawing one of the lone tiles (discarding the triplet), or toitoi by pon. In this scenario, if you can pon one of the pairs, do so and aim for toitoi.
+* With 4-5 pairs, and one of the pairs cannot be turned into a triplet, because both remaining tiles of the pair are [[Kabe#Visible Tiles|visible]], then favor chiitoitsu over toitoi.
 == Compatibility ==