Threading the Needle

Dlr: South ♠ K Q 7 3
Vul: N-S K 2
7 5 4
♣ A 8 7 6
♠ A 9 5 2
A 7 4
A K Q J 8
♣ 3
West North East South
1
2NT (1) Dbl 3 3♠
Pass 4♣ Pass 4
Pass 4 Pass 4NT (2)
Pass 5♠ (3) Pass 6♠
All Pass

(1) At least 5-5 in hearts and clubs
(2) Roman Key Card Blackwood
(3) Two key cards plus the ♠Q
Against your ambitious slam., West leads the ♣K. You win and cash the ♠K, West discarding. How do you plan to get to 12 tricks?

Solution

After checking that West was indeed void of trumps, declarer saw that to have any chance, he would need for East to hold three diamonds. With that in mind, declarer cashed the top three diamonds from his hand. When that passed off successfully, declarer played a heart to the king and ruffed a club with the ♠5.
Declarer then cashed the A and ruffed his remaining heart low in dummy. Having taken the first nine tricks, declarer led a club from dummy. When East ruffed this with the ♠10, declarer overruffed with the ♠A. A diamond was ruffed with the ♠Q, East having to underruff. That brought declarer’s trick tally to 11. Declarer then called for dummy’s remaining club. It didn’t matter whether East ruffed high or low. The outcome would have been the same: Declarer’s ♠9 would be his 12th trick.
It also didn’t matter whether declarer overruffed or discarded on the high club ruff by East. Declarer could have discarded a diamond, won the trump return and crossruffed the last two tricks with high trumps. Additionally, if declarer had arranged to be in hand at trick 10, he could have ruffed a diamond high and led a club, scoring the ♠9 whatever East did. Declarer could hardly have gone wrong!

Dlr: South ♠ K Q 7 3
Vul: N-S K 2
7 5 4
♣ A 8 7 6
♠ — ♠ J 10 8 6 4
Q J 10 9 5 8 6 3
10 3 9 6 2
♣ K Q J 9 5 4 ♣ 10 2
♠ A 9 2
A 7 4
A K Q J 8
♣ 3