Kuitan

Kuitan

Kuitan (喰い断) refers to the allowance of tanyao (all simples) as a scoring hand when achieved through open melds. The term literally translates to “eating/using simples” and represents a fundamental rule variation in mahjong that significantly impacts hand-building strategy and scoring potential.

How Kuitan plays out at the table

In standard mahjong, tanyao requires a hand composed entirely of numbered tiles from 2 to 8 (bamboo, characters, and dots), excluding all honor tiles (winds and dragons) and terminal tiles (1s and 9s). Traditionally, some rulesets restricted tanyao to closed hands only, hands where all melds were concealed and the winning tile came from the wall or the discard of another player without calling it.

Kuitan eliminates this restriction, allowing players to score tanyao even when they have called one or more open melds (chow, pung, or kong) during play. This opens significantly more possibilities for completing tanyao hands, as players can actively pursue and declare melds from other players’ discards rather than waiting passively for a closed hand.

The distinction between kuitan-allowed and kuitan-forbidden rules creates two major mahjong rule frameworks:

Ari-ari mahjong (有有, literally “has-has”) permits kuitan and represents the more permissive ruleset. This is the standard in many regions, particularly in online mahjong and casual play. Under ari-ari rules, tanyao becomes a more accessible and frequently scored hand.

Nashi-nashi mahjong (無し無し, literally “no-no”) forbids kuitan, requiring tanyao to be achieved only through closed hands. Tanyao is still worth 1 han either way; nashi-nashi simply makes the open version illegal, so an opened all-simples hand can end up with no yaku at all.

Strategic Impact

The kuitan rule significantly influences hand selection and discarding strategy. In ari-ari games, players pursuing tanyao can aggressively call tiles from discards, increasing their speed and reliability in completing the hand. In nashi-nashi games, tanyao players must exercise restraint and avoid calling melds, accepting slower completion times in exchange for the hand’s validity.

The practical consequence shows up before the first call: in nashi-nashi, a player planning tanyao must commit to staying closed from the start, because a single chii or pon strands the hand without a yaku unless it can pivot to something else. That single rule toggles the whole risk calculus of early calls.

Kuitan in practice

A player holds an all-simples hand with two called melds: a chii of 2-3-4 bamboo, a pon of 5-5-5 characters, plus 6-7-8 dots, a pair of 3-dots, and a 5-6 of dots waiting on 4 or 7 of dots.

• Under kuitan rules (ari-ari): the hand is a legal open tanyao. Win on the 4 or 7 of dots by ron or tsumo and it scores tanyao (1 han) plus any dora.

• Under kuitan-forbidden rules (nashi-nashi): the same hand is yaku-less. The two calls already opened it, tanyao no longer counts, and unless the hand can produce some other yaku it cannot legally win at all. The calls cannot be taken back, so the mistake was made at the moment of the first chii.