What to Discard: Choosing Your Wait — Good Shapes vs. Bad Shapes

If tile efficiency is about closing the DISTANCE to tenpai, wait selection is about WHICH tenpai you take. Two hands can both be tenpai, yet one wins far more often — because the shape of the wait decides your winning rate. The discard with the highest tile acceptance does not always lead to the best-shaped wait. This article covers good versus bad shapes, and how to weigh a wait's live tiles, its room to improve, and its value.

Good shapes vs. bad shapes — the wait decides your win rate

Waits split broadly into good shapes (wide acceptance) and bad shapes (narrow). The common ones — in parentheses, the kinds of winning tile and the maximum number of them:

• Two-sided wait (ryanmen): e.g. 4-5 waits on 3 and 6 = 2 kinds, up to 8 tiles. The basic good shape.
• Three-sided wait (sanmenchan): e.g. 2-3-4-5-6 waits on 1, 4 and 7 = 3 kinds (with the pair already complete elsewhere). Wider than a ryanmen.
• Nobetan (stretched pair wait): e.g. 4-5-6-7 waits on 4 and 7 — two single-tile waits, a fairly good two-point wait.
• Closed wait (kanchan): e.g. 4-6 waits only on 5 = 1 kind, up to 4 tiles (bad shape).
• Edge wait (penchan): e.g. 8-9 waits only on 7 = 1 kind, up to 4 tiles (bad shape).
• Single/pair wait (tanki): 1 kind, up to 3 tiles (you already hold one copy). A dual-pair wait (shanpon) is 2 kinds but only 2 of each = up to 4 tiles.

Count your live tiles — the shape's name vs. how many are left

Good and bad shapes are a starting guide, not the final word — what really matters is how many of the winning tiles are still live. Even a ryanmen is weak if you hold some of its tiles yourself or several sit in the discards; a kanchan with all four of its tile live can win more often. Count what you can see — your hand, the discards, and called tiles — and subtract it to get the tiles you can actually draw. The shape is the default value; the live count is the real number.

Aim for a good-shape tenpai — balancing acceptance and shape (at 1-shanten)

At 1-shanten, the discard with the most tile acceptance sometimes only reaches a bad-shape tenpai. Accepting slightly fewer tiles in exchange for a higher chance of a GOOD-shape (two-sided) tenpai often wins more in the end — a widely cited guideline is that one acceptance tile toward a good shape is worth roughly two toward a bad one. Hands that keep the option to upgrade a bad shape into a ryanmen are especially valuable. Build on pure efficiency (see the companion article), then look ahead to what KIND of tenpai each discard produces.

Tegawari — don't always snap off a bad-shape tenpai

When you reach tenpai on a bad shape (kanchan, penchan, tanki), you can sometimes decline to lock it in — stay damaten (concealed, no riichi) and wait for a tile that upgrades the wait or the value. This is tegawari, a shape or value change: if drawing a certain tile turns your kanchan into a ryanmen, it can be worth not taking the immediate tenpai. The trade-off is falling a turn behind. Tegawari pays off when there are many improving tiles, the value gain is large, and it is still early; in the late game, or against a fast opponent, just take the bad-shape tenpai and get ready.

Shape and value together — pinfu needs a two-sided wait

The wait shape also drives your score. The pinfu yaku REQUIRES a two-sided (ryanmen) wait — it does not score with a kanchan, penchan, tanki, or shanpon wait. So choosing the good shape can directly hand you a yaku, and the points that come with it. Likewise, a wait that keeps tanyao or your dora, or that lets a riichi pick up ippatsu and ura-dora, raises value. Wait selection pays off on both win rate and points: when a discard offers both a wide wait and a bigger hand, that is usually the one to play.

How to practice

Build the efficiency base first. On TsumeDojo each what-to-discard problem shows the accepted tiles and the count after you answer, so you can practice seeing exactly what each discard takes in. Once acceptance comes easily, push one step further and ask of each discard: what kind of wait does this lead to, how many of those tiles are live, and is there a way to improve the shape? That habit is what grows your wait-selection sense.