This exercise is a follow-up of the article: To finesse or not to finesse *** (published 03-02-2010 in Varia ***).

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

¹ negative

West leads the ♠K, declarer ducking. West continues with the ♠10, East still following suit and again South ducks. West now plays the ♠J, North and East discarding hearts, South winning.
How should South play?

Solution

Declarer counts eight tricks. If he gambles the finesse for either the ♦Q or the ♥K, he is down if it fails: West takes two more spades.
There is a much better line of play: declarer begins by playing three rounds of clubs, ending in his hand. Unless West turns out to have four or all five clubs (a small chance, especially since West had length in spades), the contract is safe. The lay-out is for instance (red cards have been played):

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

After thus having removed West's safe exit-cards, South now exits with a spade. West is thrown in: he is allowed to score two more spades (making four spade tricks in total), but then has to lead into a red tenace.
Note the importance of not cashing the fourth club. If declarer had cashed it, he would face a difficult discard in his hand on the last spade.
Having kept his fourth club, he is not in trouble: he can now discard that club and cling to ♦AJ4 and ♥AQ. Later he can cross to the ♦K to cash dummy's fourth club.
(Dummy has no trouble discarding: he can throw hearts).

What if West has four clubs after all? Declarer then does best by cashing the fourth club as well, followed by the ♦K and ♦A.
If the ♦Q has not come down, declarer must choose between:
1. Playing a spade (the throw-in), hoping West is out of diamonds: he has to play into the heart tenace then
2. Finessing for the ♥K.

Our Dutch visitor Johannes calculated the chances of success for these two lines of play for us. His findings: plan 1 has a success rate of 72.0% and plan 2 of 78.5%. Plan 2 assumes West's spade suit is good enough to overcall 1♠ without needing red honour cards. It also includes the chance of West showing out on the second diamond, meaning declarer can go for the throw-in in spades after all.
Thank you Johannes!