Source: http://cdn.acbl.org/nabc/2018/02/bulletins/db10.pdf

Dealer West. N/S Vul

	7 2 K 8 5 4 A 7 6 Q 5 4 2
Q J 5 4 3 Q 7 10 8 4 A J 6		A K 10 8 2 K Q J 9 2 9 7 3
	9 6 A J 10 9 6 3 5 3 K 10 8

West	North	East	South
Pass	Pass	1	2
2	3	4	Pass
Pass	Pass

Opening lead: 4

Bidding commentary: As South, your 2 * jump overcall is equivalent to an opening weak two-bid. As North, you have enough to give partner a single raise. As East, you are too strong to raise to 3.

You have a side-suit singleton, phenomenal trump support plus a strong side suit. Please.

Defensive commentary: As South, you should recognize this dummy type – one with a powerful side suit plus strong trump support. Defensive tricks must be taken or established quickly. Clearly clubs is the suit to attack.

The question is: which club to lead? When the dummy to the right has the 9-x-x-(x) and you have the Q-10-8-(x) or the K-10-8-(x), you have the 9 surrounded with the 10-8 plus a higher unequal honor, the ingredients for a “surrounding” play.

Attack with the 10, the higher of the two surrounding cards and the only card in your hand that defeats the contract. Your lead establishes two club tricks before the A can be driven out.

Assuming West covers with the J (best), North wins and returns a club. You remain with the K 8 over dummy’s 9 7. By covering the 7 with the 9 and the 9 with the king, you drive out declarer’s ace while retaining a club winner.

When partner gets in with the A, a club return defeats the contract. If you lead the 8, declarer plays low, partner wins the queen, but declarer remains with the A-J hovering over your king.

Leading the king doesn’t work either. Declarer wins the ace, draws trumps and drives out the A, all the while retaining a club stopper.

Other surrounding plays to be on the lookout for are: (1) leading the J from the AJ9(x) or the KJ9(x) when dummy to the right has the 10-x-(x); (2) leading the Q from A-Q-10-(x) when dummy to the right has the J-x-(x).