1977, Manila, Philippines. For the first time in the history of the World Championship teams (contesting the Bermuda Bowl) two teams from the same zone meet in the final. Last year's American winners, The Defenders, face the other North-American team, The Challengers.

You are seated behind 'Challenger' John Swanson. As South he is dealt:

E/NS		♠	7 4 2
		♥	A K Q J
		♦	6 5 4
		♣	7 6 3
		♠	K Q 10 9 5
		♥	10 3
		♦	A Q 8 3 2
		♣	K

¹ Natural, pre-emptive

West leads the ♥2 to dummy's ♥J.
Swanson plays a trump from dummy and hands you his cards, while East, Passell, goes up with the ♠A and continues with the ♥9. West ruffs with the ♠6 and switches to the ♦J. How do you play?

Solution

Apologies, in order not to give away the pointer, Bridgevaria has presented the problem in a somewhat unclear way. The moment of truth was the second trick. Have you, like Swanson did, carefully unblocked the ♠9 under East's ♠A? This far-sighted move proved to be crucial.

E/NS		♠	7 4 2
		♥	A K Q J
		♦	6 5 4
		♣	7 6 3
♠	8 6 3			♠	A J
♥	2			♥	9 8 7 6 5 4
♦	J 10 9			♦	K 7
♣	A Q 10 9 5 4			♣	J 8 2
		♠	K Q 10 9 5
		♥	10 3
		♦	A Q 8 3 2
		♣	K

Declarer won West's ♦J and drew the last two trumps in EW with the ♠K. Thanks to his unblocking in trick two, he was now able to enter dummy by playing the ♠5 to the ♠7. Next he pitched the ♣K on the ♥A and only lost a diamond trick: 4♥ just made.
True, EW went terribly wrong - West could simply have cashed the ♣A, after which EW will always get a diamond as the setting trick - but Swanson would not have been able to exploit EW's mistake if he had not unblocked in trumps

By the way, who made the mistake in EW? West (Hamilton), so it seems; after all he did not cash the ♣A.
On closer inspection East (Passell), is not innocent either. To the third trick (the trick West ruffed) he played the ♥9. West could see from the ♥10, dropping in South, East had carefully played his highest heart, obviously as a suit preference (Lavinthal) signal for the higher remaining suit: diamonds. Did East's rather forceful message prevent West from playing the ♣A (he obviously thought East had the ♦A)?
Let us take an even closer look: when does playing the ♣A give away the contract? Obviously, if South has a club (he cannot have more in view of the bidding), the play of the ♣A cannot cost.

But what if he has a void?
If South has another heart or two more hearts (his ♥10 in the third trick was a false card then), meaning he has a 6-3-4-0, 5-3-5-0, 6-4-3-0 or 5-4-4-0 distribution (still assuming he has the ♦KQ), a diamond return is indeed required. After all, if West now tries to cash the ♣A, South ruffs and draws the last trump(s). Thanks to two entries in dummy (the ♠7 and the third heart), he can play a diamond to the ♦KQ twice, setting up the suit if he has the 5-3-5-0 and pitching his fourth diamond on the fourth heart if he has the 6-3-4-0.

In other cases where South has a void in clubs (6-2-5-0, 5-2-6-0, still assuming South has the ♦KQ), playing the ♣A cannot cost. After all, South will always make his contract by way of the diamonds:
- If West plays the ♣A, South ruffs and draws the last trump(s). Afterwards one diamond lead from dummy is sufficient.
- If West plays a diamond, East wins with the ♦A and returns a heart. But South ruffs high, draws the last trump(s) and cashes his diamonds.

To sum it up: East was mostly to blame by suggesting he had the ♦A. If West trusts his partner in this, his only (although remote) chance of defeating the contract is, that South has another heart.
Still, West carries some guilt: wouldn't East have saved with 5♣, holding four clubs? So a club void in South looks rather unlikely, a case for cashing the ♣A first.

At the other table East was Bob Hamman. In trick three, in the same situation as Passell, he played the ♥6: a middle high heart, meaning 'no preference for any specific suit'. West, Bobby Wolff, drew the correct conclusion and cashed the ♣A. EW later made the setting trick in diamonds: down one.

+720 and 12 IMP to the Challengers, an important contribution to their 30 IMP deficit victory.