NS had a simple auction to 3NT on the hand shown. Since there was no use of Stayman, West inferred that a major suit lead would be best and led the 10H from his longer major. Declarer was happy to take what he saw as a free finesse in hearts, and played the jack from dummy. When East covered with the queen, the contract could no longer be made, no matter what declarer did next.
Let’s see how the play went. Declarer ducked the queen of hearts, won the next heart and knocked out the ace of clubs. After West won that, he knocked out declarer’s last heart stopper. All would have been well if East had held the ace of diamonds. However, as West had started with both minor- suit aces, declarer lost three hearts and two aces for one down.
So what should declarer have done? It is clear to plan for three club tricks, two diamond tricks and two in each major to provide nine tricks. The key is to avoid losing three hearts and two aces while setting up the minor suit winners.
Declarer should have played low from dummy at trick one and won the king of hearts in hand. Following the plan for nine tricks, declarer should attack clubs. If East holds the ace of clubs, he will not be able to continue hearts profitably, since he would be leading into dummy’s ace- jack tenace giving declarer three stoppers and only two losers even if the hearts are 5- 2. As the cards lie, West will win with the ace of clubs and lead another heart. Only now should declarer finesse the jack of hearts which loses to the queen. This does not matter now because East began with only two hearts and cannot continue the suit. If East began with three hearts, the suit would be 4- 3 and there would not be a third heart loser. The best East can do is to shift to a spade. Declarer wins and now attacks the diamonds to gain two tricks in that suit. As declarer still has a heart stopper at that point, the contract cannot be defeated. The only time this plan fails is when West has chosen to lead a doubleton heart and East began with five hearts to the queen and the ace of diamonds.