By the Textbook

Dlr: South ♠ K Q 10 8 5
Vul: E-W 8 6
K 2
♣ Q 7 5 2
♠ A J 9 2
A 4
A 6 3
♣ A K 1 0 4
West North East South
2NT (1)
Pass 3(2) Pass 4♠
Pass 5 Pass 6♠
All Pass

(1) 20-21 HCP
(2) Transfer to spades
Against your slam, West leads the K. What is your plan for taking 12 tricks?

Solution

Declarer saw that there would be 12 tricks if he could make four tricks in clubs. After winning the first trick with the A, hearts, declarer drew three rounds of trumps. He then demonstrated that he was a student of elimination play. First, he cashed the K, played a diamond to the ace then he ruffed his last diamond in dummy. Next, declarer made the textbook play of a club to the ace followed by a heart to endplay the defense.
If West had won the heart trick, he would have had to lead away from his ♣J or concede a ruff and discard. No matter how the defenders played, declarer would have made 12 tricks. If East had won the heart trick and had another club to play, declarer would have let in run to dummy’s queen. No matter how many clubs East had, declarer would have made the four tricks in clubs he needed for his contract. The full deal:

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