Overtricks

[Califdude]

Given IMP scoring, what is the expert player's thinking about overtricks vs risk when playing part-score contracts? What would be your opinion of a strategy to invariably make the safest visible play to guarantee making the bid against any bad trump of side-suit break, basically giving up any thought to overtricks unless they are 100% risk-free? How would you characterize your general approach to taking some risk in order to make overtricks undoubled and in a part-score contract?

 

As always, thanks for your replies.

[awm]

(1) If you are in a contract that probably will not be duplicated at most tables (or at the other table, if in a team game), don't worry about overtricks. Take the safest line. This actually applies at MPs too. For example, if you are in slam and there is a fairly good chance other people will not be in slam, making seven may not even score you ONE extra IMP. Don't worry about it. Similarly if you missed a good game that other people will probably bid, just try to make your partial. An overtrick may not save you even one imp.

 

(2) If you're in a normal contract, you can work out the IMP expectation. Basically the overtrick is one IMP, going down in a partial versus making costs about 4-6 (depending on the partial and whether it's vulnerable), going down in a game is 10-13 (depending vulnerability) and so forth. If the chance of going down by trying for the overtrick is sufficiently small then it can be worth it.

[MFA]

At imps, the priority is to make the contract. Certainly.

But for some people, the goal seems to be to arrive at exactly the required number of tricks, and I don't like that. If I'm taking a safety line it's because I know exactly what I'm doing (guarding against). Otherwise I just try to rack up as many tricks as possible to get the 1's and 2's also. These scores matters and also it's more annoying to play against somebody who fights for every trick.

[dburn]

Jeff Rubens occasionally referred to a parabolic utility function when talking about the value of playing for overtricks in teams matches (and, what is more or less the same thing, defending for extra undertricks at the risk of letting a no-play contract make).

 

By this he meant (I think) that in very short or very long matches, it was worth playing for overtricks because, other things being equal, there was enough chance that they would be a decisive factor in the outcome. In matches that were neither sufficiently short nor sufficiently long, it was a better idea just to make the contracts you were in. Whereas this is obviously true of very short matches, it is not clear to me how long a match needs to be before the utility factor dictates that you should play for overtricks during it.

 

Hugh Kelsey wrote of safety plays that if you give up a trick to guard against a low-probability distribution that will jeopardize your contract, you may for various meta-reasons be doing the right thing even though as a purely pragmatic matter you are doing the wrong one.

 

For example, needing five tricks from a suit of AKQ1043 facing 65, you might duck the first trick completely in both hands if there is no entry to the long suit, to guard against 5-0 onside. This is theoretically losing bridge - if you spend your life doing that, you will lose more IMPs than you will gain, and some of those lost IMPs may lose matches for you.

 

But Kelsey said (I am paraphrasing here because I don't have the relevant book with me) that "partner will not care about the overtricks you expect to make on 99 other deals out of 100 - all he will see is that you have put a cold game on the floor". Not upsetting partner may be worth many more IMPs than a dozen overtricks.

 

Some of these safety plays are not necessarily as safe as all that. You, South, play in 6♠ with:

 

[hv=d=s&v=n&n=sk942h432d432ca32&s=saj53hakqjdakqjc4]133|200|Scoring: IMP[/hv]

and West leads a diamond. You can of course play the trumps safely for one loser against a 4-1 break by cashing the ace and leading to the nine, but if East wins his doubleton queen or ten and gives West a diamond ruff, how unlucky were you? The a priori chance that West has ♠Q10xx is significantly greater than the chance that he has one diamond and three spades to the ten or the queen - but what is that chance now given that he led a diamond?

 

Does this answer your question? No, I thought not. Still, if bridge were an easy game, how many of us would play it?

[han]

Nice post.

 

I hope my partners don't think like Kelsey does. I believe Meckstroth is known for saying that people tend to play too safely and in doing so give up too many IMPs.