If trumps are 3-2, you will make 10 tricks in comfort by ruffing the second heart, drawing trumps and playing on clubs. You will make five trumps, four clubs and two diamonds.
However, if trumps are 4-1, this plan is fraught with danger. Indeed, you will fail on this layout:
West’s plan is to play a forcing game in an effort to shorten your holding. If he can end with more trumps than you, he may be able to develop an extra defensive trick.
Suppose you ruff the opening lead and cash the top two trumps, bringing to light the 4-1 break.
When you play on clubs, East will win and play another heart. As you have to ruff this, you will be down to the bare queen of trumps with West still holding two trumps and you can do no better than play on clubs.
If West ruffs a club you would ruff the next heart in dummy, return to the diamond ace and draw West’s last trump. In this problem he will throw diamonds instead and you will fail because he will ruff the ♦K and lead a fourth heart, forcing dummy to ruff. Now the only way off dummy is with a diamond, and West can ruff that too.
You do no better to cash your diamond winners before playing clubs. West ruffs a club and another heart sees you stranded in dummy and forced to concede a second club ruff to West.
The way to make the contract is to play on clubs after just one round of trumps. This succeeds whether trumps are 4-1 or 3-2. When East takes the ♣A and leads a third heart, you must ruff and then continue to play clubs.
