Chow

A chow is a meld of three sequential tiles in the same numbered suit. The lowest tile can be 1-7 (so 7-8-9 is the highest valid chow). Chows cannot span suits (4m-5m-6m is valid; 4m-5p-6s is not) and cannot use honor tiles. To call chow on another player's discard, the discarder must be to your immediate left. Sichuan mahjong allows in-hand chows but disallows the chi call (you can't claim a chow from a discard) — All Pungs is a scoring bonus, not a structural requirement.