What happened to Lebensohl, robot?!

[42krunner]

http://tinyurl.com/o9hhaxn

 

What did I miss?

 

-Daniel

[1eyedjack]

[hv=sn=42krunner&s=SQ875HAKQ4D873CAT&wn=Robot&w=ST92HJ5DAKJT52C76&nn=Robot&n=SJ3HT9D9CKQJ85432&en=Robot&e=SAK64H87632DQ64C9&d=s&v=b&b=7&a=1N2C!(Cappelletti%20-%20single%20suited%20--%2014-%20HCP%3B%2010+%20total%20points)3N(2-5%20C%3B%202-5%20D%3B%202-4%20H%3B%202-4%20S%3B%2010-13%20total%20points)PPP&p=DKD9D4D3DAS3DQD7DJSJD6D8DTH9H2S5D5HTC9H4D2C2H6HQHJC3H3HKHAH5C4H7CAC6C5S6CTC7CKS4CQH8S7S2CJSKS8S9C8SASQST]380|270[/hv]

Yes I have been hit by this phenomenon, and I am adding some rambling musings because I don't know all of the right answers.

 

It would be interesting to know whay would be your choice of North's action. Choices seem to be:

1) Immediate 3N (choice actually made by GIB, presumably not your preference)

2) Immediate 2N leb to 3♣ with intention of stopping there (and then what to do if they bid 3♦?)

3) Immediate 3C presumably forcing (and then what to do if they bid 3♦?)

4) Pass to find out what West's suit is, and then some combination of the above (which risks various bids being unavailable next round, including 2N or 3-level cue)

 

There are a couple of supplementary issues to consider

A) Classical Lebensohl is defined in the context that an opponent has bid a natural overcall in a known suit. This affords you the opportunity to cue bid their suit, or to make a delayed cue bid via 2N (unless their suit is Clubs, but rarely is 2♣ a natural overcall). Against Capelletti you might still retain this option but only by initially passing. There is no guarantee that 2N or even a cue at the 3 level is available on the next occasion if you pass initially.

B) West is on lead against NT, so barrage bidding will not hide the suit for opening lead purposes, but it may prevent their finding a fit/sacrifice if you deny the Capelletti hand an opportunity to show his suit.

 

Classically (ie deployed against a known suit) an immediate 3N shows a balanced hand with no major suit interest and without a guard in the opponent's suit, while 3N via 2N shows the same hand with a guard. Some players reverse the meanings of direct 3N and via 2N as regards committing to a guard. GIB system notes do not say which way it plays it and I have just lifted the classical definition from Wiki and assume that GIB plays it that way. Cue bid or delayed cue via 2N shows the same hand types but with Major suit interest (Staymanic). Against Capelletti the lack of availability of a cue bid without first finding out overcaller's suit complicates matters (in general, but perhaps not on this particular example hand which is unbalanced). That said, it is my obvservation that in competitive auctions generally, a GIB responder will assume that a partner who has opened 1N 15-17 will have a guard in the opponent's suit, rendering the cue bid less of a priority weapon (although the assumption of guard is not borne out by reality that frequently perhaps).

 

Assuming that North evaluates his hand as too strong for an immediate 3♣ signout (via 2N), which is a questionable but not outrageous valuation so let's run with it, then there may be a perverse logic to the immediate 3N call on this hand, if that bid denies a guard in the opponent's unknown suit (as it would in classical Leb if the suit were known). The only consistent hand type would be one with 3 suits unguarded and, in order to have a hand that justifies 3N, therefore one strong suit (which of course cannot be the suit held by opponent). It doesn't much help South here, as North's suit could be Diamonds and West's suit Clubs. The explanation attached to the 3N bid does not support that this is what GIB was trying to do, but neither does it support the actual hand held, so perhaps we should disregard the attached explanation as irrelevant to GIB's actual thought processes.

 

The vast majority of occasions in which a robot is at the table, then there are 3 robots and a human. The three robots, and perforce the human, all play 15-17 1N, all play Capelletti in defence thereto, and all play Lebensohl over Capelletti. That being the case, I think that the published system notes should go into a bit more detail about how it varies Lebensohl in light of the 2♣ overcall's conventional meaning which was not addressed when classical Lebensohl was invented. Furthermore, it would be helpful if the explanation of the bid given at the table paid lipservice to conforming to the hand held. I can understand minor deviations, and I can understand deviations after a long and convoluted auction. But on this occasion it was North's first call, and the deviation is not minor.