Wednesday, August 17, 2005 4:56 PM

Mathematics of Pre-empting

PITBULLS:

The science of pre-empting involves many variables. Most Bridge players realize that the number one reason for pre-empting is to make life difficult for the opponents. “Playing the vulnerability” means using pre-empts and the mathematics of the vulnerability for a gain. Right behind though at number two, is to describe your hand to partner so that she can make an informed decision either in a competitive situation or not.

There are 5 main variables involved with pre-empting a) quality of suit b) outside cards (defense) c) vulnerability d) passed hand e) hand description. Lets examine each of these in turn . You hold x K9x KJ10xxxx xx and you are vul against not and partner is not a passed hand. OK lets look at the quality of the suit first. In the worst case scenerio this suit has 3 losers and your heart king is ½ a trick. Vul you could go for –1400 with only 4 ½ tricks. Ok if you talk the opponents out of their non vul game you gain 420-170=250 which is 6 IMPs. Going for a number is losing 16 IMPS. You are gambling 16 to win 6 . A poker play would not be impressed. What if you only go for –1100 or –800 or –500 . Even 500 is losing 11 on the IMP scale so it is still 2-1 against. Bad Mathematics.

What do you do to partner when you take these type of risks ? Partner can not make any informed decision so you will cause her to go wrong most of the time. The outside heart king will just be enough to tip the scale so that they can not make anything. Bridge become straight bad gambling and any bid could be right. Bridge becomes a slot machine and you just grab the handle and see what happens. I see these type of pre-empts who are “single handed” players and do not respect partners Bridge ability. Is putting partner thru worth this type of Bridge ?

What if you are more disciplined and wait for the appropriate vulnerability or until partners a passed hand ? Do you have to be a terrorist every round of the bidding ? When partners a passed hand by all means pre-empt with that hand. If you are not vul against vul you can pre-empt with that hand in any seat. Partner will not expect the outside king but rules are made to be broken if the vulnerability calls for it. Partner always gives leeway if partner is nv vrs vul both in opening bids and pre-empts. That is an automatic adjustment. With equal vulnerability I do not open 3♦ either as the pot odds are not right. I will lose more than I can hope to gain in the long run.

Weak two’s with bad suits and not respecting the vulnerability is the same thing. BJ and I have changed our doubling style when playing against those players at the 3 level and two level. When they are vul and we are not , we are permitted to double directly or in balancing with any distribution as long as we have quick tricks. These auctions get converted for huge numbers more often than not. Smart players allow the vulnerability to guide their decisions. Rather than bid a non vul 3NT they convert when the opponents are vul. Why give the opponents extra options at unfavourable vulnerability ?

Lets discuss hand description. There are no rebids in Bridge to aptly describe 7 , 8, or 9 card suits after you have opened at the one level. A Tormentee had this hand nv vrs vul tonight. ♠AKQ10xxx ♥K ♦xxx ♣Jx in first seat. Playing the vulnerability, I would open 4♠. This jams them out of their vul game/slam if they have one. Opening 1♠ allows the vultures in & is there a rebid that shows these spades with no defense on the outside ? The Tormentee opened 1♠ and my partner and I were allowed to exchange information so that we knew we had the balance of power. They did sacrifice against our vul game for –300 but they lost a lot of IMPS because 4♠ ( being opened ) bought the hand undoubled at many tables.

I have strong feelings on bad pre-empts & not playing the vulnerability . Saying they are a matter of style is a cop out. They really mean that you have no respect for partner as she has no input into the decision and gets taken down with the rest of the team when these operations fail. To me , bad pre-empts are just a bad psyche as is opening a flat 11 with no quick tricks or not having quick tricks for opening bids. You put partner at risk just like any 1^st seat psyche. Testing partner’s patience with these types of bids will result in a high partner turnover. Is it worth it ?