Chii is the only meld call restricted to the player on your left (the kamicha): it claims their discard to form a run (shuntsu) of three consecutive tiles in one suit, for example 3-4-5 of pin. Only numbered tiles (man, pin, sou) can be called this way, never honors, which cannot make a sequence. The completed group is then laid face-up, with one tile rotated to show where the call came from.
After chii, reveal the two matching tiles and then discard. Under Tenhou rules, pon or daiminkan takes priority over chii when several calls target the same tile. WRC 2025 gives priority to the first clearly announced group call; when announcements are simultaneous, pon or daiminkan takes priority over chii. Kuikae, including discarding the same tile or the opposite end of the called run, is forbidden.
Calling chii opens the hand, removing riichi, menzen tsumo, pinfu and uradora. Before calling, identify an open yaku already present or still reachable, then compare speed gained with value, flexibility and safe tiles lost.