Play these hands with me - playing in a suit contract

Play these hands in a suit contract: when to ruff, when to draw trump.

[@paulbernadini431]

Thanks!

[@andrewwebb4635]

Very interesting as usual! But why does East discard the Cl K in hand 5, please? I assume it’s a signal of some sort but don’t understand it. He doesn’t know yet that south only has a single club.