In rec.games.bridge Steve Conover wrote:
What’s the best book or article explaining how to decide when to double for penalties (in match-point pairs, or just in general)?
To which Frances Hinden sent this thoughtful reply:
don’t think you need a book, you need good judgement & practice. The principles are fairly simple.
A. Matchpoint pairs (and point-a-board) is a totally different game to imps or rubber. One of the biggest differences is in doubling for penalties.
1. Understand the scoring.
1a. If you were making +110 but not +140 in 2S and the opponents bid 3D which is going one off vul or 2 off non-vul, you need to double to get a good score. If it is going 1 off non-vul you may need to bid 3S and hope for a mis-defence.
1b. If you were making a vul game and they find a good save, you only double if you are fairly certain either you aren’t making at the 5-level or that the save will be universally found. Otherwise you may need to bid at the 5-level even if it’s a poor contract, just to get back to average.
1c. Be cautious about defending doubled part-scores if you are making 3NT. +500 is very few matchpoints if +600 was available. However if you aren’t making game then +200 or +300 is a top against your partial.
2. Develop a good partnership understanding.
2a. As you are frequently doubling for 1 off, you will concede doubled partscores. Some of these will be virtually the same matchpoints as if you hadn’t doubled (that’s why you doubled), some of them will be zeros. Get used to it.
2b. Work on your partnership defence. Although the matchpoints may be the same for -110 or -470 it feels much, much worse if you have just let the contract through.
3. Develop good judgement.
THE ONLY REALLY IMPORTANT PRINCIPLE THAT YOU REALLY NEED.
It’s one thing to say you have to double if you were making your partial, or if you aren’t making game your way. It’s another to work it out in the auction. Every time you have a competitive auction – particularly a partscore auction – think before you see the hands is this making? is our contract making? How many matchpoints do I expect if this makes, goes off? At the end of the evening, look carefully at the frequencies. Would you have done better to bid on? To double? Which of the partnership should have done so?
This is a completely different ballgame. Double if it’s going off. Particularly if it’s going lots off. I need to do some work so I’m not going to write a great deal more, but judgement is still very important – only a different sort of judgement. In short:
1. Understand the scoring
Defending for +500 with a possible +800 is fine against your vul game; taking 300 is less good. Don’t double partials into game for one off. Double sacrifices more often; the last thing you want to do is bid on and go off.
2. Increasing the penalty increases your score
Sounds obvious, but not true at matchpoints. If they go 3 off vul in a stupid game, you get a top at matchpoints whether or not you doubled. At imps +800 will be worth a lot more than +300. At imps you expect to concede 590 & 790 more often than at pairs (it’s only 3 imps out) in exchange for some juicy penalties. However conceding doubled partscores is to be avoided. When they double you at imps, remember you have a redouble card. That increases the score even more.
3. Development good judgement
Whenever one of their contracts goes 2 or more off, think: could I have foreseen this? would my double have helped declarer or the defence?