Building a Fence Around Partner

This was Board 1 from the 2025 USA Senior Team Trials Final:

Vul:None Dlr: East	K5  K1082  85  Q10987
Q7  AQ93  A1042  532		962  J7654  K763  6
	AJ10843  --  QJ9  AKJ4

East dealt and passed and South opened 1. West made a questionable (pushy?) A double to show the other suits takeout double and North showed clubs (via a 1NT transfer). East bid 2 and South made a An unusual jump showing 0-1 in that suit and support for partner Splinter Bid of 4. North's 4 bought the contract.

West astutely led a club; he expected his partner had shortness and might get a ruff(s). As you read the play to the first few tricks, try to decide what was a mistake and what was not.

Declarer won the A and played a spade to the king and a spade finesse to the jack, losing. West gave partner a ruff and East played a diamond to South's J and West's ace. This was the position:

Vul:None Dlr: East	--  K1082 8 Q109
--  AQ93 1042 3		--  J7654 K76 --
	A1084  -- Q9 J4

West has to get this right to set the contract. The A would let declarer ruff and then throw both remaining diamonds (one on a club and one on the K). West must avoid trying to cash the A here to set 4. And what about declarer's play? IMHO, it was correct. Sure, we can see that banging down the high spades (as happened at the other table where E-W never bid) would mean 11 easy tricks. But with West's takeout double, declarer decided West was likely to hold spade shortness. Playing the A-K of spades would fail if East started with Q962.  East would win the 3rd spade and cross in diamonds to get a ruff.  

Given that declarer played correctly, should West figure out not to lay down the A at the key moment? Not really. If he trusts his partner, he should try to cash the A, playing for declarer to have started with: 

AJ10843

4

KJ

AKJ4

 

On the Real Deal, declarer did play as described. But East didn't. East built a fence around his partner. After obtaining the club ruff, East (envisioning partner's potential problem) thoughtfully cashed the K in the position shown. Then another diamond produced the setting trick, without West having to work up a sweat. If East doesn't play the K and West has faith in his partner, he should assume declarer has the K.