N/S were playing 2/1 with 15-17 NT and  five card spade suits.  The 1NT rebid showed 11-14 and two diamonds was game-forcing checkback. After controls were shown in the other three suits, North showed three key cards, which must be the spade king and the aces of hearts and clubs.  South now knew that the slam could not be worse than the heart finesse, and may be better.  For example, if North held the club jack then it would be 100%  In the event, the combination of the heart finesse and the club suit made it about 70%, which is fine for a vulnerable slam at teams.

A diamond was led; declarer ruffed the second round and drew trumps.  Taking the simple line, declarer checked for clubs 3-3, and when East held J10xx he took the heart finesse, which lost for one down.

It was pointed out by a Manchester expert that the slam could have been made.  Can you see how?

Solution

After drawing trumps, declarer could lead the queen of hearts from hand before revealing anything else about his hand.  If West covers then the slam is made.  If it isn’t, then declarer rises with the ace (a Vienna Coup) and runs off all the spades.  After the last spade is played, declarer has four cards remaining, the heart jack and KQx of clubs and dummy has ace, nine to four clubs.  East, on the actual hand, needs to keep the heart king and all the clubs and hence is squeezed.  This line works if either defender has the heart king and four clubs.   On this line there could be a complication if East follows to the second club with an honour.  Declarer will have to decide whether East started with C JTx or C Hx.