The contract at most of the tables was either Four Spades by North, or Five Clubs doubled by East.
When the defenders began with two rounds of clubs against Four Spades, North's losing heart went away on the second club and 11 tricks rolled in, while a heart lead held the contract to 10 tricks.
But how do you play on the lead of a small club to the ace followed by a switch to the queen of hearts? Playing teams, you should duck; but this is pairs. All those who received this defence rapidly took their ace of hearts and tried to enter dummy with a diamond in order to discard their losing heart on dummy's queen of clubs. Unlucky!
East ruffed the diamond and put partner in with the king of hearts for a second diamond ruff. One off.
Five Clubs should, of course, be one off, but was made on a number of occasions when North, who was in with the ace of hearts, failed to cash the ace of spades. The kindly disposition of the heart suit meant that declarer, after cashing the ace of clubs, was able to discard dummy's singleton spade on her fourth heart and ruff her three spades.
4A Q J 10 6 4
#A 10 7 3
48 4K 9 7
!K 9 6 !Q J 8 4
#8 6 5 4 2 #void
28 4 3 2 2A J 10 9 7 5
45 3 2
!7 5 3 2
#K Q J 9