Chiitoitsu

Chiitoitsu

Type	Yaku
Kanji	七対子
English	Seven pairs
Value	2 han (Closed only)
Speed	Medium
Difficulty	Medium

Chiitoitsu, also known as chiitoi or niconico, is one of the standard yaku hands. This hand consists of seven pairs, where no two pairs may be identical. In other words, every pair must be distinct. This hand is one of the two exceptions of the "four melds and one pair" rule of forming a hand, where the other exception is the kokushi musou. This hand is closed only.

Tile diagram

Winning tile:

Value

By default, this hand is always given 25 fu. In addition, a chiitoitsu tenpai always uses a tanki machi (wait). Normally, that wait pattern is awarded 2 fu but not in this case. Finally, the 25 fu number is not rounded up to 30 fu. In turn, the scoring table produces an independent set of point exchanges applied to chiitoitsu hands. Although, the 25 fu column is equivalent to 50 fu numbers.

High scoring chiitoitsu hands are possible without dora. The highest possible involves riichi, ippatsu, tsumo, tanyao, and chinitsu. Add the 2 han for chitoitsu, this combination brings the hand to a whopping 12 han. Then add haitei or houtei, then such a hand becomes a kazoe yakuman.

Formation

Given the number of pairs in this hand, it is often tempting to call pon with matching discards to the pairs. However, it is generally noted that toitoi is actually a slower developing hand in this instance. This is especially the case, when the potential chiitoitsu hand sits at iishanten; and it may actually be recommended to let the hand develop into a chiitoitsu tenpai.

Nevertheless, transition to other yaku may actually be favorable, if the hand develops at least one ankou. In this case, players may find themselves looking to develop a toitoi hand, sanankou, or even suuankou. Whatever the case may be, this consideration does take some discretion, particularly when taking into account the number of tiles available, current point standing, and/or number of tile draws remaining.