If hearts are 4–3, you can easily make a grand slam by winning the first trick and ruffing a heart, but because this is IMPs you must prepare for a 5–2 heart break, maybe even a 6–1, perish the thought.
The mandatory play at trick one is to duck the first trick (you’ll see why soon enough), win the likely spade return, cash one high club, and then the ♥A K. Now let’s consider the critical distributions of the East–West hands to see why this is the best line of play.
1. West has two clubs and one heart. West ruffs the second heart, but can’t put East in to lead a trump, so you can ruff a heart and get rid of your remaining heart on a diamond.
2. West has two clubs and two hearts. West ruffs the third heart, but can’t put East in to lead a trump, so you can ruff your remaining heart.
3. West has one club and two hearts. Cashing one club first allows you to ruff a heart and make an overtrick. Even if you failed to cash one high club first, you still make your contract. After West ruffs the third heart, and can’t put East in, you can ruff your remaining heart.
Now the East hand (the one you don’t want to be short in hearts):
1. East has two clubs and one heart. If East ruffs the second heart, and can’t put partner in to lead a trump, you make the contract as you can ruff a third heart, etc. If, however, East refuses to ruff the second heart, you will eventually lose two heart tricks. Down one. Tip: Sign up East as a future partner.
2. East has two clubs and two hearts. Forget it, you can’t make the contract.
3. East has one club and two hearts. You make an overtrick. Had you not cashed a high club early, you still make your contract because East can’t put West in to lead a second trump after overruffing dummy on the third round of hearts.
Clearly the key play is to duck the first spade. Cashing one high club is also best.