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12 opposite 12

#1 User is offline   mikestar 

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Posted 2008-June-12, 10:39

I've been rereading some old books from my bridge library and I ran across the revised edition of the KS system book.

KS advocate that opposite a 12-14 weak NT, if you hold a balanced hand without major suit prospects you should bid game with 12 and pass with 11.

I've found this works out well at the table--the majority of 12-12 hands offer at least a reasonable play. Passing 11 will lose if and only if partner would have accepted a 2NT invitation and game makes. Passing 11 is a big gain if 7 tricks or fewer are the limit and you break even there are 8 or more tricks are available but opener would have declined the invite. Add to that some additional penalties when fourth hand balances too aggressively, and I'm convinced that this is a winning strategy. It also opens up systemic possibilities as you don't need 2NT natural or a substitute sequence for it.

KS also state that 12 opposite 12 will make 3NT more often than 20 opposite 6. I suspect this is also true and would like to hear the experience of others.

If this is indeed correct, it has some important implications for hand evaluation and system design.

Do any of you Zar Points advocates have some statistics about the comparable proposition in Zar evaluation? Does 25 ZP opposite 25 make 3NT more often than, say, 38 opposite 14?
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#2 User is offline   kenrexford 

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Posted 2008-June-12, 11:40

I don't know anything about Zardoz points.
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However, the GP is about right, IMO. Fairly well known theory.
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#3 User is offline   NickRW 

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Posted 2008-June-12, 11:46

OK, last question first. I'm a big fan of zar and similar systems for hand valuation when it comes to suit contracts (so much so that I think milton work, in that situation, should be consigned to the history books). However, though 6421 + 2a+b-d is a maybe a little better than 4321 + 1/2/3 for shortages (i.e. points according to Goren) in NT contracts (as documented on Zar Petkov's site) the simple truth is that both the 6421 and 4321 methods of counting honours do FAR better by ignoring distribution. Distribution is maybe worth a tiny bit, but we're talking half and quarter points worth. In short I wouldn't worry about too much about zar points specifically in relation to NT.

It is also true that 12 opposite 12 is a little better than, say, 15 opposite 9 and definitely better than 20 opposite 4. Whether I'd go so far as to say that 20 opposite 6 is also worse than 12 opposite 12 I don't know. It is a long while since I played about with my database of double dummy results - but I seem to recall that when your high card strength is split 3:1 or 4:1 it is maybe worth being pessimistic by a point and when it gets to more like 6:1 deduct another. So, if that is correct and KS are saying 12+12 is better than 20+6, then I think that is close to being right, but maybe a shade too pessimistic.

Another thing about raising to 3 with exactly 12 is that you will maybe get slightly better results if you refrain from doing so with hands that are devoid of intermediates - and intermediates with an honour, especially a jack, are better than those on their own or which only support an ace. The annoying thing is that to evaluate this with numbers gets you into halves and quarters again - you really need to develop a feel for it if you don't want to crowd your head with fractions.

With regard to simply raising to 3 with 12 and passing with 11 in general, KS are not the only ones to note this. I have an oldish book "Do you play Stayman" by Samuel Stayman - and the same advice is in there too.

Another thing to note about the 2NT contract is that, especially at imps, the window in which it is worth being in that contract is very narrow indeed. The slightest bit more and it is worth going for the game bonus and anything less you might as well stay in 1N and protect yourself against the bad breaks by simply taking a plus.

So, by all means, use 1N-2N for something other than invite to 3, your results will be fine. I have little table experience of whether this also applies to the 15-17 NT as well (I live somewhere where the weak NT is everywhere), but I suspect that to be the case.

Nick
"Pass is your friend" - my brother in law - who likes to bid a lot.
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