A Valuable Overtrick
This is based on a Real Deal from ACBL’s 2017 Instant Matchpoint Game. As South, with both sides vulnerable, you hold:
♠ 6 4 ♥ K J 10 9 8 7 3 ♦ Q 8 ♣ A 7
Perhaps this hand is too strong to preempt, or you don’t like all the cards on the side, but I’m fine with opening 3♥. Left-hand opponent doubles and partner raises to 4♥. Everyone passes and LHO leads the ♠Q.
It looks like you’ll lose at most a trick in each side suit. Even if trumps are 3–0, you will play for the takeout doubler to have the void by starting hearts with the ace. Likely, you are playing for an overtrick. You can’t do anything about the spade loser, but you should try to get rid of a club on the diamonds.
If you win the ♠A to play a diamond to the queen, it loses to the king. West plays a spade to East’s king and a club switch is won by your ace. Hearts are 2–1, but you have no overtrick. Here is the Real Deal:
After winning with the ♠A, a diamond to the 8 is the wining play. Why would you do that? From West’s takeout double and the lead (♠Q), you can place the ♠K with East and almost all the remaining high-card points with West. He must have both minor-suit kings. When the ♦8 loses to the jack, West plays a spade, but that is the last trick for the defense. Why? Later on, you will play your ♦Q, which West must cover. Then, when you ruff a diamond, the 10 falls, making the 9 good for a club discard. Lucky? A little, but worth trying. (Note: Declarer should be careful when playing a heart to the ace to retain the 3 in hand, so he can later reach dummy for the good diamond.)
Squeeze experts will note that the overtrick can also be made by ducking the first trick. West can eventually be squeezed in the minors.
If I had titled this article Intrafinesse, I would have given away too much information.