Fuente: 
I remember it like it was yesterday, although it was about 20 years ago. I was playing with my regular partner, Skip Anderson, when an interesting hand came up. I was playing West.
My partner looked at her hand, replayed the auction in her mind, and looked at her hand again. She asked if it was her lead. Confirmed that it was, she calmly announced, “Double”.
My right hand opponent, Jerry Harris, knew Skip well, and he knew that if Skip doubled you, you were going down. With very little further thought, he bid 7. Everyone passed. Suddenly, I was the one on lead. Clearly, the opponents were not off two aces. It was a near certainty that my partner was staring at an ace-king combination that she was going to cash against 6NT, but possibly not against seven clubs. What’s worse, I had no real clue which suit my partner had that contained those good cards. There was a chance that the opponents had 13 tricks if we couldn’t take the first one or two, so now I had to figure out which suit from my Yarborough hand to lead.
This column is not about whether or not I found the winning lead (I did), but rather when you should or shouldn’t double. Note that Skip would have been far better off passing, and setting the contract. If I can’t find a diamond lead, N-S will have 13 top tricks.
When the opponents bid a voluntary slam, (ie., they’re not sacrificing against you), you aren’t going to get rich by doubling. Generally, at best you can hope to beat them by one. When you have a trump stack, you may be certain they will not succeed, but you can’t be certain they won’t run to 6NT, which you may not have a prayer of beating. When the opponents have stopped in a contract you can beat, don’t chase them away from it. Does this mean you should never double a slam? Absolutely not. There are three times when it’s perfectly permissible to double their slam.
- 1. You are on lead. You know what to lead. They can’t run anyplace safer.
- 2. Your partner is on lead. They have no chance no matter what partner leads.
- 3. Your partner is on lead. You need a specific lead from partner to beat the slam.
Examples one and two just don’t come up very often unless you are regularly playing against very weak opposition. Three, however, comes up from time to time, and it can be one of the most powerful gadgets in your toolbox. It is known as a Lightner Double. The guidelines for a Lightner Double are as follows:
- 1. Lightner doubles are made against high level contracts, usually slams.
- 2. The double asks for an unusual lead.
- 3. The unusual lead can never be a trump, nor a suit that you or your partner have bid.
- 4. The unusual lead will rarely be an unbid suit.
- 5. The unusual lead cannot be a suit dummy bid as a Blackwood response as you would have doubled it then. If the contract is No Trump, it will often be one of the suits bid by dummy – usually, the first.
Why these specific rules? It’s quite mathematically sound. You aren’t doubling to get rich. As I said before, you can’t hope to beat them by more than one trick. Why risk minus 1,210 or minus 1,660 to net an extra 50 or 100 points?
You are doubling to wake up partner that you believe there is a lead that may beat the contract. What you are really risking is that you can be +100 instead of -980, or +200 instead of -1430. That’s a gamble that’s worth the risk.
The majority of the time the double will tell your partner that you are void in a suit, with a desire to ruff. Partner will be responsible for figuring out what suit that is by looking at his own hand. If you double 6H and partner’s hand is 2-2-3-6, he will lead a club. If it turns out you had a diamond void, it’s just one of those things. Not everything will always come out the way you want it.
If you think that a lead of an unbid suit will give you the best chance to beat the contract – DO NOT DOUBLE!! Partner is likely to lead that suit without the double. If you double, you insure that partner will not lead the suit you want.
Suppose you overcall one spade and the opponents have a Blackwood misunderstanding and end up in 6NT. You are staring at AKJxx, with partner on lead.
Oh, it’s tempting to double. Why be +100 when you can be +200 or maybe even +1100? The reason is that if you go plus on this hand, one that clearly belongs to the opponents, it will be a tremendous score. Plus 100 will likely be the same top as +1100. At IMP scoring you will be +13 instead of maybe +17. You don’t need to double to get a good score. You just need for partner to lead the suit that you expect him to lead.
However, what if you overcalled 1 holding: KJxxx xxx AKxx x? The opponents end up in 6NT with partner on lead. How can you tell him NOT to lead a spade? You guessed it. Of course he may not lead a diamond either. He may lead a heart or a club. The double doesn’t guarantee he will find the right lead, it just gives you a chance. If you bar a spade, your chances are one in three.
The auction and partner’s hand will often narrow it even further. Have you figured out how I found a diamond lead 20 years ago? Skip didn’t double. I knew a club was wrong. Dummy was known to hold four hearts, and declarer rated to hold four spades. (He did use Stayman after all). A heart or a spade lead would have been unusual, since it is one of the opponents’ suits. Skip didn’t ask for an unusual lead. (She wouldn’t have doubled 4 for a heart lead, as that might have eventually been trump.) That just left diamonds. I’m really glad she didn’t have ace-king in one of the majors, as then she might have doubled, and I would have had at least a 50 percent chance of getting it wrong. Those who know me know that I get 50 percent chances wrong about 85 percent of the time.
The moral of the story: If the opponents volunteer to go down, you should let them.