Obstacle courses

This month, you’ll solve a defensive problem which is often treated the wrong way at the table but which becomes completely approchable if you take the trouble to ask yourself the right questions. You are sitting South in a teams match and hold the following hand:

A quick auction results in 6 Spades by East:

What do you lead?
Leading the singleton trump (2 points) is dangerous because it may doom your partner’s honor. A Heart lead (2 points) can only help declarer develop dummy’s second suit, promised with his 4♦ bid (major two-suiter). The lead of the Jack of Diamonds (8 points) has the merit of being neutral and sometimes establishing the setting trick (with the Queen doubleton in dummy and the King in partner’s hand) before declarer sets up his Clubs. The risk, however, is to see the trick you could take with the Club Ace vanish into thin air – or even your two immediate tricks, which can happen when your opponents bid a slam without going through a cue-bidding sequence. In the end, leading the Ace of Clubs (10 points) wins by a little margin. You discover the dummy: