West led the ace then five of spades to dummy’s queen. Declarer was very happy with her contract until, that is, West showed out on the second round of trumps.
Although declarer does not have another heart in dummy to lead to pick up East’s trumps, it may still be possible to make the contract via a trump coup.
Though dummy’s diamonds are all winners, it is ruffing diamonds that is the key to success on this deal.To succeed, it is necessary for declarer to reduce her trump length to match that of the opponent to be couped. After winning the second spade in dummy, declarer plays ace and king of hearts, getting the bad news.
The ace and king of diamonds are followed by a diamond ruff, a club to the ace, and a second diamond ruff.
Having shortened her trumps sufficiently, declarer now plays a club to the king and leads winning diamonds through East, trapping the jack of hearts.
Do you see the importance of shortening declarer’s trumps to the same length as East’s?
If, in the ending, South had three trumps to East’s two, she would have to ruff at trick eleven and would no longer be in the correct hand to trap the opposing heart holding at trick twelve.