Not every ready hand is equal: its structure decides how wide the wait is (how many tiles win). Know your type and you know how strong your hand is — and how to read an opponent who's ready.
Two-sided waitopen wait
Two consecutive tiles (e.g. 3-4 of Characters) — either neighbor (2 or 5) completes the run. Waits on two tiles; the best partial shape.
Closed waitmiddle wait
Two tiles with a one-tile gap (e.g. 3 and 5) — only the middle tile (4) completes the run. Waits on one tile; narrower than two-sided.
Edge waitedge wait
At the very edge of a run: 1-2 can only wait for 3, and 8-9 only for 7 — the other neighbor doesn't exist.
Single waitpair wait
Four melds done and only the pair missing — hold one lone tile and wait for its copy. Flexible but only one tile.
Dual-pair waitshanpon
Two pairs in hand — any tile matching either pair upgrades it into a triplet. Waits on two tiles, both hard for opponents to hold back.
Multi-waits: wider is better
When a hand decomposes in several ways, the waits stack into a multi-wait of three or more tiles. The classic shape: 2-3-4-5-6-7-8 of one suit waits on 1, 4 and 7 — three ways. Multi-waits not only win more often, they're nearly impossible to defend against — the direction to aim for as you improve.