After your slightly pushy jump to 2♠, your partner had had an easy raise to game. West starts with the ♥K, which you win with the ace. At trick two, you run the ♠9 to East’s king. East exits with the ♦9. How will you get to 10 tricks on this deal?
Declarer was surprised and disappointed when the spade finesse lost to East’s king. After some thought, declarer decided that East was very unlikely to hold any of the unseen high cards, so he rose with the ♦K and led a club to the jack and queen. After cashing the ♣A, declarer ruffed the ♣8 with the ♠J, West discarding a heart. Declarer led a trump to dummy’s 10, then cashed the queen of trumps. Declarer paused to consider the situation. West had started with three trumps, five hearts and two clubs, so he had an original 3=5=3=2 shape. As West had discarded a heart on the third round of clubs, he must have three hearts and two diamonds remaining.
So declarer advanced the ♠A and threw a heart from his hand. West threw a heart – a diamond seemed pointless – and was then put on play when declarer exited with a heart. After cashing his remaining winner in hearts, West was forced to exit with the ♦10. This was run to declarer’s jack for the game-going trick. Notice that if declarer had won the diamond shift on the table, he would no longer have been able to make his contract. Simply put, there would not have been sufficient entries to draw trumps, ruff a club and cash the ace of trumps. Of course, if he had made the technically inferior move of leading a low trump at trick two, he would not have faced this difficulty on the diamond return at trick three The full deal: