Toitoihou
| Type | Yaku |
|---|---|
| Kanji |
対々和 対々 |
| English | All triplets |
| Value | 2 han |
| Speed | Medium |
| Difficulty | Easy |
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;[n 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 (none are triplets), keep the options open for chiitoitsu or the regular hand structure. At only 4 pairs and no triplets, toitoi can be done if every pair is easy to pon or if there is a another yaku to "fall back" upon, otherwise wait for a 5th pair or a triplet to form.
- With 4 pairs and one turns into a sequence or triplet, it can be best to go for the regular hand structure. This may or may not be toitoi. If the hand is poor (e.g., mostly 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 reach chiitoi tenpai by drawing one of the lone tiles (discarding the triplet), or toitoi 1-shanten by pon. In this scenario, if you can pon one of the pairs and the rest of the pairs are possible to pon, 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
^ 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 |  |
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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
- Toitoihou in Japanese Wikipedia
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