Tenpai

Tenpai is a term used in mahjong to describe the state of a hand that is one tile away from winning. In a standard hand, which consists of four melds (pungs or chows) and one pair, a tenpai hand can be completed with a single draw or discard that provides an agari tile, allowing a win.

The term originates from Japanese riichi mahjong, where tenpai (天牌) literally means a ready hand. It is used across most mahjong variants to indicate that a hand is poised to win on the next appropriate tile, whether the winning hand is the conventional four melds plus a pair or a special hand such as Seven Pairs.

Tenpai is determined by examining potential winning tiles and the hand’s structure. The wait for the final tile is described by several shapes, including ryūmen (ryanmen) a two-sided wait for two possible tiles, kanchan a middle wait, penchan an edge wait, and tanki a wait for a pair. The efficiency of a tenpai hand often depends on these waits and on tile safety during discards.

Shanten is a related concept that measures how far a hand is from tenpai. A hand in tenpai has shanten zero, while larger shanten numbers indicate greater distance from readiness. Players use shanten calculations to guide discards and draws, aiming to reduce distance to tenpai.

In play, reaching tenpai is a central strategic objective. Players weigh which tiles to keep or discard to maximize the chance of completing a hand, all while considering opponents’ potential waits. In riichi mahjong, a player in tenpai may declare riichi, wagering points to indicate readiness and potentially increase payout if the hand wins.