After a pass by West, North opened One Club and East chose a good moment for an unorthodox pre-empt of Three Spades. This forced South to take a guess at Four Hearts and all passed.
West led the eight of spades and East, after winning with the ten, followed with the ace and king. Declarer ruffed the third round successfully with the jack of hearts, crossed to dummy with the ace of diamonds, and led a trump.
Convinced that he had found South's weakness,
East went in with the ace of hearts and played a fourth round of spades.
This did not worry declarer unduly for, after he had trumped in hand, it did not matter whether West over-ruffed or not - there was still a trump in dummy.
In either case, East's queen appeared on the second round of hearts and it was all over. Suppose that East had not gone in with his ace of trumps on the first round of the suit but had contributed the queen? South wins and leads a trump to dummy's eight and East's ace.
Now a fourth round of spades does promote a second trump trick for the defence.Reuse content