The ace of clubs lead held the first trick and West made the obvious shift to the jack of diamonds — low, low, ace. South ruffed a club, cashed the ace and king of hearts to discard a diamond, and ruffed a heart in his hand. Declarer led his last club and ruffed it in dummy as West discarded his remaining heart. Dummy’s last heart was ruffed by South with the king of spades as West declined to over-ruff, shedding a diamond instead. South had started this line of play, eliminating both hearts and clubs from his hand and the dummy, in the hope that East held the singleton ace of spades and could be end-played with that card.
Declarer led a low trump from his hand and saw West rise with the ace and lead another spade as East discarded clubs on both tricks. South had been paying close attention and he realized that his contract was now a sure thing. East had shown up with seven clubs, four hearts, and no spades. That left him with two diamonds, only one of which was remaining.
Declarer left the last trump outstanding and confidently led a low diamond toward dummy’s queen. Should West have the king of diamonds, dummy’s queen would be the tenth trick. Should East have that card, it would now be singleton, and he would have to give a ruff-sluff, taking care of the remaining diamond loser. Well done!