Doubling a slam

When is it right to double a slam? Only when it’s going down!

I'm not being facetious. It pays to be very conservative about doubling the opponents when they’ve bid a slam under their own power (e.g., without being pushed in a competitive auction). In general, only double a slam when you’re certain to defeat it with tricks in your own hand. 

BUT... there is one situation where doubling a slam has a very specific meaning…

♠  x x x    ♥ A J x x x   ♦ Q J 10 x x  ♣ --

South	West	North	East (you)
1 ♣ 2 ♠ 3 ♠ 7 ♠	Pass Pass Pass Pass	1 ♥ 2 NT 4 ♦ Pass	Pass Pass Pass ?

Yes, your left-hand opponent just jumped to 7♠. Yes, really. What do you do?

ANSWER: Double, requesting that partner make an unusual lead – a club in this case – so that you can ruff.

THE PRINCIPLE: This is called a Lightner double, named after Theodore Lightner who devised this way back in the 1930s. If the opponents freely bid a slam, a double by the third hand – the defender that is not on opening lead – requests an unusual lead in order to defeat the contract. The player on lead is expected to figure out which suit that would be.

Your partner’s hand

♠  x x   ♥  x x x x  ♦ x x x   ♣ 9 8 x x
From the auction, partner knows that declarer has a fistful of black cards -- at least a 6-5 in clubs and spades. North bid 2NT, promising at least 2 clubs. With partner's four clubs, at least 12 of the clubs are accounted for, so it appears to partner that you are likely void in clubs. Partner leads a club, and badda-bing badda-boom, down one.

Figuring out which suit to lead. The Lightner Double calls for an unusual lead, and there is a rough outline for figuring out which suit that might be:

1. If the defense has bid a suit, don't lead it. Leading our suit would not be unusual.
2. Don't lead trump.
3. If dummy or declarer has bid a side suit, that would be a likely choice.

But most importantly, the player on opening lead must think through the auction and her hand in order to reason out which suit partner wants led.

Note that against a six-level contract, only make a Lightner double when you have another sure trick in addition to the ruff.

The dog that didn't bark. If you are on lead against a slam, and partner did not double... Partner did not ask for an unusual lead, so by implication she's not looking for a ruff; you should make a normal lead, whatever that happens to be given the cards you hold.

The complete hand:

	North
	♠ Q x x ♥ K Q x x ♦ A x x  ♣ 10 x x
West		East (you)
♠ x x  ♥ x x x x ♦ x x x  ♣ 9 8 x x		♠ x x x ♥ A J 9 8 x ♦ Q J 10 x x  ♣ --
	South
	♠ A K J x x ♥ --  ♦ K x  ♣ A K Q J x x

Without the Lightner double, West might not find a club lead. 7♠ makes against any other lead.