South opened One Spade and North responded Two Diamonds. When South's Two Hearts rebid was raised to Four, South jumped directly to Six Hearts, against which West led his D10.
This is one of those curious hands in which you may just as well be in the grand slam, as you are likely to make either 11 or 13 tricks on a diamond lead. Any other attack is safe for 12 tricks, barring bizarre breaks. If HQ falls, dummy's three losing diamonds are discarded on the long spades, and a diamond ruff in dummy produces 13 tricks.
Declarer felt the lead was unlikely to be away from the king; he also noted West had not led the ace of the unbid suit, clubs, so was unlikely to hold it.
South rose with dummy's diamond ace, on which he discarded the jack from hand.
When nine cards are held between two hands, there is a minimal percentage difference between cashing the two top trumps or finessing for the trump queen.
South decided to put pressure on East as, if he held the trump queen, he might not risk following with his DK, as he expected it to be ruffed. Declarer played a trump to the king and ran the jack. The psychological ploy worked - in with HQ, East now tried to cash CA. South ruffed, drew the last trump and played as described above, for 12 tricks.
East-West game; dealer South
!A 9 3 2
#A Q 6 3
2J 6 3
410 9 8 47 2
!7 !Q 6 4
#10 9 8 2 #K 7 5
2K 10 8 7 4 2A Q 9 5 2
4A Q J 6 4 3
!K J 10 8 5