Use a key spot to key in the play

Alexander Graham Bell said, “Before anything else, preparation is the key to success.”

That certainly applies to bridge; and while counting winners and losers, keep your eyes open for key spot-cards.

In this deal, how should South play in six spades after West leads the diamond queen? Would his line change if dummy's spade nine were the spade seven?

When North raised spades, South launched Roman Key Card Blackwood, learning that his partner had two key cards (two aces, or one ace and the trump king) but no trump queen. South, knowing they were missing an ace or the spade king, signed off in six spades. (Yes, he might well have bid six no-trump, especially in a pairs event, where the extra 10 points could be worth a lot of matchpoints.)

Declarer can afford one trump loser, not two. If the suit is splitting 2-2 or 3-1, there won't be a problem.

If East has all four, playing the ace and another works fine. But that fails with this layout; West would get two trump tricks with his king and 10.

South must not overlook dummy's spade nine, which provides a finessing position if West has all of the trumps. At trick two, declarer should lead a low spade to his queen. West wins and plays another diamond, but South takes the trick, cashes the spade jack and leads a spade to that key nine.

If dummy has only the spade seven, the contract must fail if West has four spades. So, declarer might as well start with the ace.