Benefits of calling
A call completes a set immediately and can skip opponents' turns. Late in a hand or with a valuable honour pung, calling is often correct.
Costs of calling
Calls reveal your plan, reduce flexibility and, in many systems, reduce value. In riichi you lose the option to declare riichi and lose closed-hand yaku such as pinfu and menzen tsumo.
A simple test
Ask: after this call, does my hand still have a way to score? Does the call make me meaningfully faster? If both answers are yes, call. If not, wait.
Style differences
Hong Kong rewards calling for valuable pungs; riichi rewards caution; American play requires calls only for exposures that fit the card, and never for concealed hands.
