Playing online Monday night, South (vulnerable vs. not) was in 4♠ (hands rotated):
♠ K 10 9 5 2
♥ A Q 10 4 3 2
♠ 8 7 ♠ A 6
♥ J 6 ♥ K 9 8 7
♦ Q J 9 5 3 ♦ A 4 2
♣ K 9 6 2 ♣ Q J 10 5
♠ Q J 4 3
♦ 10 8 7 6
♣ A 8 7 3
West North East South
Pass 1♥ Pass 1♠
1NT 4♠ All Pass
West led the ♦Q to the king and ace. East shifted to the ♣Q taken by South. At this point he decided to play for a crossruff (setting up dummy would have been a better plan). He led the ♦7 and ruffed in dummy. He continued by playing the ♥A and another ruffing low as the jack fell.
Declarer continued with his plan and played the ♣3 and ruffed with the ♠5 in the North hand. South next led the ♥4 and ruffed with his ♠J. The ♦8 was ruffed in dummy with the ♠9 and the ♥4 was led and ruffed by declarer with the ♠Q.
South continued by leading the ♦10 and ruffed with the ♠10 in dummy and overruffed by East with the ace. She led the ♣J to make dummy ruff with the ♠ K and declarer was down one.
Let's return to the point where declarer played the ♥A and another ruffing in his hand. When the ♥J fell, he could have shifted gears and drawn trump to make his contract. In fact, at this point he can make five, according to Deep Finesse. He can lead a low spade to the 10. Assuming East wins (ducking is no better), she takes her best shot by leading a low heart. Declarer ruffs with the ♠J, ruffs a club or diamond in dummy, ruffs another heart (dropping the king) with the ♠Q. The dummy is now good, and it's a simple matter to return to dummy to draw the last trump and claim.
Making 4♠ with an overtrick would have been worth 6.77 IMPs to North-South. Instead, going set one trick was a minus 7.23 IMPs, a difference of 14 IMPs.
Most North-South pairs were in 4♠, but one North played 1♥ and three East-West pairs played either 1NT or 2NT. You can see all the results by clicking here.
See Karen Walker's bridge site about forming a plan for declarer play by going here.