Is A Good time Make a “Penalty” Double When Your Defensive Tricks Exceed Your “Allowance”?

Question

Most contracts are predicated on the supposition that the defenders will win some tricks. If game can be made with "26 points and eight trumps," this leaves 14 points and five trumps to the defenders as an "allowance."

The defenders' 14 high card points gives them an "allowance" of at least three tricks. (They actually have the material for four tricks, but it is assumed that the declarer will be able to "ruff," or otherwise neutralize one of them.)

Suppose one defender has JT98x of trumps. He has the whole trump "allowance" for his side. More to the point, this holding will take two trump tricks, whereas if they were split 3-2 (which occurs 68% of the time), these five trumps would take zero tricks.

Absent the jack of trumps, the defenders have an "allowance" of 12-13 high card points which should be good for three tricks. Their two trump tricks are clearly above their "allowance." Does this fact make this a good time to double for penalties?

And how do you guard against the possibility that the double will scare the opponents into a better contract, or that revealing where your strength lies would cause declarer to alter his play and make the contract?

Answer 1

How long is a piece of string?

There are few guarantees in Bridge, but if the opponents have bid up to a contract that you think is over-optimistic, then you weigh up the extra points you'd be giving your opponents if they somehow make against the significant rewards you'll receive if they fail, and act accordingly.

I used to play a lot of casual Bridge online, and while it's a little bit odious, there was a phenomenon known as the "Pogo double" (Pogo being the name of the site). If the opponents are going to win the match anyway if the contract makes, you might as well double them, just in case against all the odds they fail. There was no conceivable downside, so people did it, even though to my mind it was somehow "not cricket"!

Your concerns about helping the opponents find a better contract by doubling them are very sensible. I think in such situations you just have to look at your hand and consider, what do my opponents not know that I know here? If, for instance, you have 5 cards in their proposed trump suit, doubling is all very well but will alert them of the unfortunate split. Even if they don't "escape" to a different contract, by making the double you told them to watch out for an unusual lie of cards, and this may help them make a game they might otherwise have lost due to incautious play.

I'm not sure there are any hard and fast rules, but I think you generally only want to make a penalty double if you're certain of your defensive position, or near as dammit. There's a lot that can go wrong when the opponents have been warned that's something up, and generally you get a lot more egg on your face when you double opponents into game, or give them their "insult bonus", then when they go down one or two undoubled as opposed to doubled!

Answer 2

Here is something of a "compendium" of answers from the site. The first thing to note is whether the opponents are bidding rationally or not. One "irrational" situation arose in the comments with thesunneverset, when opposing partners seem to be 6-1 or 7-0 in each others' suits, and are obviously bidding against themselves in a "mIsfit." Then a penalty double is clearly called for.

The rest comes from a link provided by arabhyata, who declined to answer for himself.

http://www.bridgeaholics.com/articles/classics/SJSimon.html

But if the opponents are bidding rationally, the time to double is when they are surprised. Such a surprise might be if they bid game with a 5-4 fit, and you had KQJT, or maybe QJT9, or JT9xx (in an eight card fit). Your cards happen to be stronger because they are connected than they would be individually, and your opponents won't count on you having ALL of them. Ditto, in the NT example I gave if you are sitting "west" in relation to a NT bidder, with KQJxx and two side kings.

On the other hand, you might refrain from doubling with a "strong" hand, or something like Jxxxx. Your opponents will probably go down if you keep quiet, but may find a squeeze or endplay if you warn them by doubling.

Answer 3

I am slightly more cautious than the average good duplicate player, but not much so. I only double when I can "see" where the defensive tricks for a two-trick plus set will come from. One obvious exception is aggressive part-score doubles at matchpoints when the opponents are vulnerable, and a +200 is usually tied for top.

Update - To address the question more precisely:
Definitely not!
Using this as your guideline will cause you much pain, as astute declares use this additional knowledge to make their doubled contracts. Regularly. Often the only reason declarers go down on bad distribution is that they don't know to protect against it, or can't correctly determine which defensive hand will have it. Give them this knowledge, and the edge is theirs instead of yours.