[thepossum]

Hi all

Yet another topic. Everyone (including me) except for one went for the sacrifice or were in part scores on this. I would like to say I had a scientific process for the decision but it was not related to the game score, more a comparison of different undertricks in S vs H

What are the considerations. It's related to doubling too. To me 4H looked gettable (but could go down on lie of cards) so sacrifice was reasonably easy call for me but no science . But I could have been doubled so??

Any tips on evaluation of such hands and risks. I know a bit about score comparisons and different approaches eg rule of 500. But my judgement is often more basic than that and probably wrong.

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[The_Badger]

Most bridge players use a formula based on the Law of Total Tricks. (I assume that you are not familiar with this as you haven't mentioned it).

https://en.wikipedia...of_total_tricks

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[nullve]

 The_Badger, on 2018-November-04, 01:39, said:

Most bridge players use a formula based on the Law of Total Tricks.

I think most bridge players don't, although they should unless they can come up with something better.

[helene_t]

OK, let's try to apply the law. Your side obviously has 9 trumps. Opps may have 5+4, 5+5, 6+4 or 6+5, so let's give them ten trumps. That's 19.

So the LOTT says that there are 19 total tricks. So one side can make 10 and the other can make 9. Either way, bidding 4♠ is good. Maybe one side can make 11 and the other 8. In that case, bidding 4♠ is also good.

Are there any negative corrections? We have no singleton and no minor honours in our trump suit. That suggests a mild negative correction. So there might be only 18 tricks. If both sides can make 9 tricks, bidding 4♠ is bad. If one side can make 8 and the other 10, bidding 4♠ is good.

As it happens, there were only 9+9=18 total trumps and a negative correction because West's ♠QJ4 is useful in defense only. So 17 total tricks. With 17 total tricks, bidding 4♠ is always bad, although you might get a decent score as opps forgot to double you.

Bidding 4♠ is normal. This time it didn't work. Stuff happens.

[The_Badger]

 nullve, on 2018-November-04, 04:20, said:

I think most bridge players don't, although they should unless they can come up with something better.

law of total tricks + experience + intuition + gut feeling = whether I should bid or not

and for those of you that enjoy a spot of light reading...

http://www.bridgeweb...al%20Tricks.pdf

[thepossum]

 The_Badger, on 2018-November-04, 01:39, said:

Most bridge players use a formula based on the Law of Total Tricks. (I assume that you are not familiar with this as you haven't mentioned it).

https://en.wikipedia...of_total_tricks

.

Hi

I am starting to use it. I understand the basics of it but still find it somewhat mysterious in certain circumstances. I clearly use it for basic limit bidding but in competitive auctions havent become that scientific yet. Ive also started reading about ODRs



Thanks everyone for all the comments

PS I didn't expect to go down 3 (we all went down 3, dont know if we could all do better). I should have said that. I weighed up likely game vs going down 1 or 2 (possibly doubled). But not based on much science, just feeling looking at my hand and balancing up that each side was weak for game, approx 22 total points each. Based on distribution, yes? But if we added up the actual (borderline) result on lie of cards there are 7/8 spade tricks and 9 hearts = 16/17 tricks. But I know maybe that is an unlikely break of cards

Are there ODR approaches to evaluating my hand

[sfi]

 thepossum, on 2018-November-03, 20:06, said:

What are the considerations. It's related to doubling too. To me 4H looked gettable (but could go down on lie of cards) so sacrifice was reasonably easy call for me but no science . But I could have been doubled so??

The Law of Total Tricks is a useful guide, but you can overthink it. My immediate reaction looking at this hand was that I have useful values for partner and not much defence. If either 4H or 4S is making it is right for me to bid, and I can't judge accurately enough to know whether or not this is the case just looking at my hand. Furthermore, at IMPs the downside is likely to be less if I bid 4S and am wrong than if I pass and am wrong. So I bid 4S here.

Today it turns out to be wrong in theory. Both 4H and 4S go down 1, although 4H can make if North doesn't lead a club early enough. 4S-3 looks like more tricks for the defence than is truly warranted.

[thepossum]

Dear all

On same topic. Another hand where I should have bid 4S over 4H but didn't. Sadly both contracts make here and if you are lucky 4S is doubled. Even more sadly I tried to make the decision using LTT instead of my brain and ignored vulnerability

If I get this right there are 18 total tricks plus adjustment for singletons.

I'm not sure about best defence but I think 4S makes and 4H+1. Is this a case of instability with many tricks.

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[nullve]

 thepossum, on 2018-November-05, 07:00, said:

On same topic. Another hand where I should have bid 4S over 4H but didn't. Sadly both contracts make here and if you are lucky 4S is doubled. Even more sadly I tried to make the decision using LTT instead of my brain and ignored vulnerability

If I get this right there are 18 total tricks plus adjustment for singletons.

If both sides can make 4M, there must be at least 10+10=20 total tricks.

Adjustment for singletons?

 thepossum, on 2018-November-05, 07:00, said:

I'm not sure about best defence but I think 4S makes and 4H+1.

NS can make 11 tricks in spades by finessing diamonds through West.

If NS play in spades (on a 9-card fit) and EW in hearts (on an 8-card fit), then there are only 9+8=17 total trumps but 11+11=22 total tricks, so LoTT is off by no less than 5 total tricks!!! Some of those can be accounted for by the presence of a double double fit, but in order to account for all of them I think we need a much better understanding of how the quality of double fits translates to total tricks.

Note that if EW play in clubs instead of hearts, LoTT is "only" off by 3 total tricks. And those can be accounted for by the presence of a double double fit (surely worth 2+ total tricks) and the absence of cards that only contribute on defence (surely worth 1+ total tricks).

[helene_t]

4♠ is a bit of a gamble but a reasonable one, I think. You are lucky to find p with a diamond fit and a singleton club. And with the ace of spades so that you can prevent a diamond ruff. Partner's four hearts are not surprising on the auction and it's a bit lucky that partner's highest heart is the 9 so that we don't have any defensive heart tricks.

That said, you have substantial extra values. There is synergy between having extra shape and having 9+ trumps. Partner makes a positive noise so accept.

It is of cause easy with all four hands open, but I like to think I would have bid 4♠ in practice.

The LoTT works extremely poorly on this hand, obviously. 17 total trumps but 21 or 22 total tricks, depending on whether you get the diamond finesse right or not. Key is here the double fit which the auction doesn't show. If partner had made a fit-showing 3♦ bid, it would have been an easier decision, but probably that would require better diamonds.

Give partner xxxx-KJxx-xxx-KJ and 4♠ would not work as well. So it is a bit of a gamble. Maybe someone can make some sims?