As South, you bid to 3NT, playing IMPs. West leads a fourth-best ♠5. What’s your plan?
You have eight top tricks: two spades, one heart, three diamonds and two clubs. You can easily make your contract if diamonds split 3–2. Can you find a ninth trick if diamonds are 4–1?
The lack of entries to dummy prevent you from ever setting up a fourth diamond trick when diamonds
are 4–1. One option is to take a heart finesse after cashing your top three diamonds – that line only works when both honors are with East, roughly a 25% proposition. A better line of play is to fall back on clubs, hoping that the suit splits 3–3, but that only occurs approximately 36% of the time. The best line combines your chances in both diamonds and hearts.
At trick one, win the ♠A. Play the ♦A Q, overtaking with the king. If diamonds are 3–2, you can play another diamond and claim 10 tricks. The overtake maneuver costs you an overtrick but grants you an additional entry to dummy, an entry you will want when diamonds are 4–1.
If an opponent shows out on the second round of diamonds, turn your attention to the heart suit for the needed tricks. Play a heart. If you lead the ♥10
and East ducks, you must be careful to unblock the ♥9 from your hand so that you can take three finesses. If you lead the ♥8 or ♥7, play low if East ducks. After any heart lead, if East rises with the ♥K, win the ace and claim nine tricks.
Let’s say West wins the ♥Q and returns a spade. Take another heart finesse. If you previously led the ♥8 or ♥7, now lead the ♥10. Finesse again if necessary. As long as the heart honors are split, which happens roughly 75% of the time, you will win three heart tricks.