After North opens 1NT, a Disneyland sequence lands you (South) in 7♥. West leads the ♦K. Plan the play. Hearts are 3–2.
In 7♥, you start with 12 winners with many chances for a 13th.
Ruff the opening lead (you don’t want to commit to a black-suit discard at this point), and draw trumps, discarding a spade from dummy. Cross to the ♣A, ruff a diamond, return to the ♣K, and assuming the queen hasn’t appeared (your 13th trick), discard a club on the ♦A and ruff a club. Assuming clubs were not 3–3 and dummy’s fourth club has not set up (your 13th trick), you are still quite a bit alive.
All hands have been reduced to four cards. You have K–x of spades in dummy along with a low club and a low diamond. In your hand are four spades. If either defender started with four spades and four or more clubs, that defender has been squeezed and either the club is high or the spades will run. If either defender started with four spades and six diamonds, that defender has been squeezed and either dummy’s diamond is high or the spades will run. In addition, you make the contract if spades were 3–3.
Incidentally, the play would be the same if dummy’s club were A–K–10–4, though you could afford to lead the ♣J the first time you led the suit to coax a cover even though you are not planning to finesse.
West leads the ♠9. Plan the play
It is way too big a play to duck the opening lead in 7NT. If hearts break 3–2 or if the♥J is singleton, you have 14 top tricks. Therefore, you need a Plan B to cater to 4–1 hearts. Here it is:
Win the ♠A, cross to the ♥A in case the jack drops, but if it doesn’t, no more hearts! Cash the ♦K Q and the ♣A K Q (hoping clubs break or the jack drops) and then cross to the ♠K. If the clubs are good, play the ♦A and the ♣10 squeezing either player who happens to have four hearts and the ♠Q.
If the ♣10 is not good and hearts are 4–1, you are still alive if either defender started with four hearts, the guarded ♠Q and four clubs to the jack. Let’s say it is East, who is more likely to hold the ♠Q than West (based on the opening lead). This is the five-card end position:
On the ♦A, East is squeezed in three suits. Say he releases a club, postponing the agony for another trick. On the now-established ♣10, East must discard the ♠Q. South now takes the last three tricks with the ♠J and ♥K Q.