Directly over Notrump, four clubs asks for aces. The responses are as follows:
4 diamonds zero or four aces
4 hearts one ace
4 spades two aces
4 NT three aces
North, with a balanced 15 points opens 1 NT. South could transfer to clubs and then ask for aces, but he wants the lead coming to his unprotected kings. It also could be useful to have his singleton heart hidden. He bids Gerber directly asking for aces. South will therefore be declarer at a club contract.
South asks for kings with his bid of five clubs. This could help him better place the contract in 6 clubs, 6 NT or 7 clubs. South picks the safe and reasonable contract of 6 clubs. There is a lot of squirming room with 6 clubs but not with 6 NT.
Contract: 6 clubs
Opening lead: Ten of diamonds.
A passive lead against slam is the best and top of a sequence makes the choice of the ten of diamonds the best.
The opening lead is won and the trumps are drawn. Part of the squirming room comes from the ruffing finesse. With AQJ10 opposite a doubleton or longer, declarer will take the standard finesse (by playing to the queen), however, with AQJ10 opposite a singleton heart, declarer will take the ace and play the queen. South ruffs if the queen is covered.
Otherwise South pitches a loser. East ducks since he knows South (from South’s card play) has a singleton. South plays the three of diamonds and the trick holds. South plays the jack which East covers and South ruffs. Now, South plays the six of diamonds on the ten of hearts and makes all of the tricks.
Result: Six clubs plus one for +940.
– North is always the passenger and must resist the temptation to try for a better matchpoint score of 6 NT. South, having the most information about both hands, is the captain.
– A ruffing finesse is not possible without touching honours if North did not have the jack. Declarer must decide whether to take a standard finesse or to ruff out the king.