Chicken-hearted Lebensohl

[Bbradley62]

[hv=sn=bbradley62&s=SA643HAK74DQ9CJ76&wn=Robot&w=SJ85HJ8652DA52CQ8&nn=Robot&n=SQT92HQ3D84CAK943&en=Robot&e=SK7HT9DKJT763CT52&d=w&v=o&b=8&a=PP2D(Weak%20two%20diamond%20--%201-4%20%21C%3B%201-3%20%21H%3B%201-3%20%21S%3B%2010-%20HCP%3B%20twice%20rebiddable%20%21D%3B%209+%20total%20points)D(3-5%20%21C%3B%202-%20%21D%3B%203-4%20%21H%3B%203-4%20%21S%3B%2013+%20total%20points)P2N!(Lebensohl%20-%20Forces%203C%20by%20partner%20--%2011-%20HCP%3B%2012-%20total%20points)P3C(Transfer%20completed%20--%203-5%20%21C%3B%202-%20%21D%3B%203-4%20%21H%3B%203-4%20%21S%3B%2013-18%20total%20points)PPP]360|270[/hv]

[iandayre]

Very valid point I have noticed often but haven't seen discussed in the forums. The bots play a very non-standard form of Lebensohl where a 3 level bid in a lower suit is a virtual game force. The rest of the world plays it showing positive but not forcing values, somewhere in the 8-11 range.

 

By now I have become convinced that the level of bridge expertise of the programmers is no better than the lower end of advanced.

[1eyedjack]

By now I have become convinced that the level of bridge expertise of the programmers is no better than the lower end of advanced.

 

I think that there are some "players" in the team, but I worry that one of two factors are in play:

 

1) there is a lack of consultation with the better players in the team, or

 

2) the way that the entire GIB system is programmed is flawed in such a way that to correct some obvious shortcomings is disproportionately problematic from a programming viewpoint.

 

 

 

[cloa513]

[hv=sn=bbradley62&s=SA643HAK74DQ9CJ76&wn=Robot&w=SJ85HJ8652DA52CQ8&nn=Robot&n=SQT92HQ3D84CAK943&en=Robot&e=SK7HT9DKJT763CT52&d=w&v=o&b=8&a=PP2D(Weak%20two%20diamond%20--%201-4%20%21C%3B%201-3%20%21H%3B%201-3%20%21S%3B%2010-%20HCP%3B%20twice%20rebiddable%20%21D%3B%209+%20total%20points)D(3-5%20%21C%3B%202-%20%21D%3B%203-4%20%21H%3B%203-4%20%21S%3B%2013+%20total%20points)P2N!(Lebensohl%20-%20Forces%203C%20by%20partner%20--%2011-%20HCP%3B%2012-%20total%20points)P3C(Transfer%20completed%20--%203-5%20%21C%3B%202-%20%21D%3B%203-4%20%21H%3B%203-4%20%21S%3B%2013-18%20total%20points)PPP]360|270[/hv]

North GIB has 13 TP.

[1eyedjack]

North GIB has 13 TP.

 

12 TP. It does not count a shortage point for Qx. So it is *just* within system spec.Not a sensible system spec, but within it.

[cloa513]

12 TP. It does not count a shortage point for Qx. So it is *just* within system spec.Not a sensible system spec, but within it.

It also says less than 12 TP.

[1eyedjack]

It also says less than 12 TP.

 

 

My reading of "12- Total points" is "12 or fewer"

[Bbradley62]

12 TP. It does not count a shortage point for Qx. So it is *just* within system spec.Not a sensible system spec, but within it.

Why is "11- HCP; 12- total points" not a sensible system spec? North is a passed hand, which is what sets these limits. And North could have as little as a Yarborough with many clubs and be planning to pass South's forced 3♣ response.

[1eyedjack]

Why is "11- HCP; 12- total points" not a sensible system spec? North is a passed hand, which is what sets these limits. And North could have as little as a Yarborough with many clubs and be planning to pass South's forced 3♣ response.

 

We are agreed that North could hardly be stronger in context of being a passed hand.

The purpose of Lebensohl is to split North's ranges into sensible sizes, so that South, who is unlimited, can decide whether to continue on to game on an informed basis.

 

There are two possible ways of achieving this:

 

Option 1: Lump maximum hands into 2NT (in which case South can freely bypass 3C and indeed any other suit that he does not want to risk being passed), so that a direct 3-suit in advance to the X would be very weak, or

 

Option 2: Lump minimum hands into 2NT, so that a direct 3-suit bid in advance to the X shows values. Then doubler is under pressure to bid 3C over 2N unless having something very special.

 

Option 2 is the standard, and dare I say it the more sensible. That being the case, it is not sensible for North to be indicating a minimum in context (via 2N) when he really has a maximum.

[Bbradley62]

Maybe I don't really understand how Lebensohl works over a weak 2 (being primarly accumstomed to using it over NT interference), but if North has a balanced 11 HCP with a diamond stopper, wouldn't the auction go:

[hv=d=w&v=0&b=8&a=pp2ddp2np3cp3nppp]133|100[/hv]

whereas the balanced 11 count without a diamond stopper would go:

[hv=d=w&v=0&b=8&a=pp2ddp3nppp]133|100[/hv]

 

If so, then the 2N can still be anywhere from 0-11 HCP. I certainly agree that the posted hand should not drop at 3♣, which was the meaning of my post and heading.

[iandayre]

In lebensohl over a Weak 2, advancer never bids 3NT without a stopper. Doing so after partner's 1NT opener makes sense, since opener will often have a stopper. A takeout doubler isn't expected to have a stopper. Of course it is true that sometimes he does.

 

Over a Weak 2M, 2NT, then 3NT over 3C shows a stopper plus 4 of the other major, with the direct 3NT denying 4 of that major.

 

At least that's what the books say. Not sure if GIB has been so programmed.

[1eyedjack]

Maybe I don't really understand how Lebensohl works over a weak 2 (being primarly accumstomed to using it over NT interference), but if North has a balanced 11 HCP with a diamond stopper, wouldn't the auction go:

[hv=d=w&v=0&b=8&a=pp2ddp2np3cp3nppp]133|100[/hv]

whereas the balanced 11 count without a diamond stopper would go:

[hv=d=w&v=0&b=8&a=pp2ddp3nppp]133|100[/hv]

 

If so, then the 2N can still be anywhere from 0-11 HCP. I certainly agree that the posted hand should not drop at 3♣, which was the meaning of my post and heading.

 

May I put it another way?

 

In your variant of Leb, what is the definition of 3C response to X?

 

 

 

[iandayre]

If you are asking me, 3C or any 3 level suit advance below opener's suit shows 8-11. Bidding a minor would usually deny 4 of an unbid major.

 

With the actual hand in question, I'd bid 2NT followed 3S, showing invitational values with exactly 4 spades. A direct jump would be invitational with 5+.

[1eyedjack]

If you are asking me,

I was asking Bbradley62, as I am still trying to understand how he concludes that Gib's choice of 2N is reasonable.

 

The possession of the 4th Spade is certainly an issue. If you are committed to showing Spades (which Gib clearly was not), which necessarily requires concealing Clubs, then 2N followed by 3S is reasonable. An immediate 3S would be forcing and an overbid on this hand (but still possible despite being a passed hand). 2S would be an underbid. So if the plan is to bid Spades then 2N is the Launchpad.

 

But GIB decided that bidding Clubs was preferable. You may disagree with that but I don't think it outrageous. Doubler does not promise 4 Spades although I would expect 3. If you are committed to the 3 level then I am prepared to trust Gib's assessment that a plus score is more likely in Clubs. Penalties for going down score the same regardless of major v minor

 

If game is on, ie if doubler is prepared to bid again over a value-showing 3C, then there remains room to find Spades. If doubler passes then you might regret not having bid 2S but at least you got your values across.

 

To my mind, the greater programing fault with Gib on this hand is its decision unilaterally to drop dead in 3C on a maximum hand, and the possession of a 4th Spade is an annoying side issue. Next time this happens, Gib won't have a 4th Spade, that distraction will disappear, and yet as currently programmed Gib will still unilaterally drop you in 3C.

[Bbradley62]

I was asking Bbradley62, as I am still trying to understand how he concludes that Gib's choice of 2N is reasonable.

I'm not defending GIB's choice of 2N; I'm defending the provided definition of 2N, which you seemed to object to. I guess I have to read more about using Lebensohl over weak 2s, but it doesn't appear to me that this one bid can be said to limit North's hand more than the original pass already has.

[1eyedjack]

OK then perhaps we do not differ.

 

The explanation of 2N is fine, because *some* of the followups by North (ie 3S via 2N) would show a full value game try.

 

But North's subsequent pass of 3C is not consistent with a hand of such power. If bidding 2N with the intention of dropping 3C (which intent is demonstrated by its actually dropping 3C in practice) then I would be very surprised to find a North with more than about 7 HCP, maybe a bad 8.

 

There is no issue with the explanation of 2N here, because there is only so much space in which to fit the explanation, and it tends to include the broadest possibility.

[steve2005]

I find Gib very bad at adjusting bidding for a passed hand. Often when you balance as a passed hand Gib thinks you have a monster.

 

From an unpassed hand signing-off in 3♣ is reasonable. I still think it's the wrong choice but not the worst bid Gib ever made.

 

But from a passed hand Gib should be doing something encouraging that's not forcing. I believe that would be 3♣. Having the 3-bids as game-forcing is a waster, it's just not gonna happen enough and often these game-forcing hands will be flawed anyways or they would have opened. However it is useful to show 8-11 pts and deny 0-7 pts.

 

 

 

[Bbradley62]

But North's subsequent pass of 3C is not consistent with a hand of such power. If bidding 2N with the intention of dropping 3C (which intent is demonstrated by its actually dropping 3C in practice) then I would be very surprised to find a North with more than about 7 HCP, maybe a bad 8.

Completely agreed! Hence, the existence of this thread.

[Stephen Tu]

Direct 3♣ would be my third choice. For the umpteenth time, I will cry out for GIB to show unbid 4 cd majors ahead of longer minors in response to takeout doubles. There's just so much more upside to finding a major fit between getting to 4M and outbidding the opps at a lower level.

 

IMO :

10: 2nt ! forcing 3c, then 3s = 4 cd S, invitational (not universal standard treatment, but a reasonable somewhat common approach, unfortunately there is almost no standard for Leb over weak 2 as to the meanings of delayed 3nt/cue/3OM)

8: direct 3s = invitational (if above is implemented this should show 5 + spades inv)

2: direct 3c = 8-11 pts, clubs (should DENY 4 cd S IMO)

2: 2S (massive underbid but at least you get to spades at MP, and partner might be able to find a raise)

0: 2nt and pass 3c

[uva72uva72]

I agree completely with Stephen Tu's comments, to include his plea for emphasis on major-suit responses to take-out doubles (while adding that this is particularly desirable when the opening bid was in the other major).

 

It's puzzling that the robot will make a negative double to show 4 cards in the other major with enough values for a free bid while suppressing a minor suit as long as 7 cards yet will suppress a 4-card major in response to a take-out double (when an 8-card fit is a high probability) in order to bid a minor suit.