After the first two tricks, declarer knew what was going on: East had switched to a singleton heart and was hoping to put East in with a diamond to the queen so as to get a heart ruff.
Declarer had three certain losers (two diamonds and a trump), so he could not afford to suffer a heart ruff. Declarer observed that there was no chance that East would have defended this way with a singleton in spades. He also saw that he needed East to have the ace of trumps – otherwise East would always get a heart ruff.
Declarer knew that his only chance to make 10 tricks was to cut the transportation link in diamonds between the defensive hands. So, after playing low from hand on the heart shift and taking the ♥J with the king, declarer led dummy’s ♣2 to his ace and continued with the ♣Q to dummy’s king. He then advanced the ♣10 from dummy and was relieved to see East’s ♣J appear.
As planned, declarer threw the ♦10 from his hand. East felt that the chance of getting a heart ruff had likely disappeared, but he played the ♦8 next. Declarer ruffed this with the ♠9, then played the ♠K. East took his ace of trumps and returned a trump. Declarer now claimed 10 tricks: five trumps, three hearts and two clubs. The full deal:
