In the balancing seat, bid was intermediate

If today’s South had jumped to three hearts in the direct position, his bid would have been preemptive. (A few pairs agree to treat it as intermediate; almost nobody uses it as the old-fashioned strong variety.)

But in the “passout” or “balancing” position, South’s bid was intermediate, suggesting a good six-card suit with opening values or a bit more. To define a balancing jump-overcall as weak and pre-emptive would make no sense. North could reasonably have passed, but he judged that his aces sufficed to bid game.

Since South had a sound hand, North’s raise appeared to be a winning action. But after West cashed the king of spades, he led the queen of clubs. Declarer won and took the A-K of trumps, relying on a normal 3-2 break, but West discarded. South then exited with a spade, hoping West would lead a third spade, but West led the 10 of clubs.

South won, took the K-A of diamonds and ruffed a club, but he had to lose a trump to East’s jack plus a diamond. Down one.

There was nothing about the auction that careful play wouldn’t justify. At Trick Three, declarer must concede a spade. He wins the club return and takes the K-A of trumps. If East-West followed, South could lead a diamond to his hand and draw the missing trump for 10 tricks.

When instead West discards on the second high trump, South ruffs a club, takes the K-A of diamonds and ruffs dummy’s last club. At the 11th trick, he exits with his diamond loser and wins the last two tricks with the Q-10 of trumps behind East’s J-9.