Bug report-- Suggestion Remove Lebensohl convention

[DBarbour]

I have seen the robots get confused by Lebensohl before, but this one is pretty bad.

 

#49 ACBL Robot Duplicate (12 Boards) - IMPs Hand 8. I wasn't able to save the hand but this should be enough information to find it. Player DBarbour. 2 Passes, my left hand opponent bids 2 Spades, weak two. I hold 7 Clubs to AKQJ, Singleton A Heart, Kx Spades, Qxx Diamonds. Opposite the right hand, it easily makes slam. Partner robot bids 2NT with a balanced hand, A of Diamonds and A Spades. Just about the right hand to make slam.

 

But now the computer has gotten lost and thinks its 2NT bid was Lebensohl. I clicked on the 2NT bid and that is what it said. It now thinks it has a long weak diamond suit and asks me to bid 3 Clubs so it can transfer to 3 Diamonds. I would bid Clubs anyway, so I bid 3 Clubs, Robot bids 3 Diamonds (4 to the A). I correct to 5 Clubs. Robot bids 5 Diamonds.

 

I strongly suggest the fix is to remove Lebensohl from the robot's memory. Its not that useful a convention and it is especially harmful with the wrong hand types, which it is when the robot gets confused. I don't remember what happened the last time I got into this hole, but I think it was pretty bad.

 

Have others had this issue with Lebensohl?

 

Thanks,

David Barbour (DBarbour)

[smerriman]

I can't access the hand (BBO admins could) - there seem to be a few missing elements in your story (you said two passes then LHO opened and then GIB bid 2NT) - I'm guessing you meant your RHO opened, you doubled, and your partner responded 2NT, something like this:

 

[hv=https://www.bridgebase.com/tools/handviewer.html?lin=st||pn|human,~~M631s9t9,~~M1562g1y,~~M5303sle|md|2SK7HADQ64CAKQJ973,S52HQJT542DJTCT64,SA63H986DA983C852,SQJT984HK73DK752C|sv|b|rh||ah|Board%2036|mb|P|mb|P|mb|2S|an|Weak%20two%20bid%20--%201-4%20!C;%201-3%20!D;%201-3%20!H;%206+%20!S;%206-10%20HCP;%207+%20total%20points%20|mb|D|an|3-5%20!C;%203-5%20!D;%203-4%20!H;%202-%20!S;%2013+%20total%20points|mb|P|mb|2N!|an|Lebensohl%20-%20Forces%203C%20by%20partner%20--%209-%20total%20points%20|mb|P|mb|3C|an|Transfer%20completed%20--%203-5%20!C;%203-5%20!D;%203-4%20!H;%202-%20!S;%2013-18%20total%20points|mb|P|mb|3D|an|4+%20!D;%209-%20total%20points%20|mb|P|mb|5C|an|5-%20!C;%203-5%20!D;%203-4%20!H;%202-%20!S;%20biddable%20!C;%2013-18%20total%20points|mb|P|mb|5D|an|4+%20!D;%209-%20total%20points%20|mb|P|mb|P|mb|P|]400|300[/hv]

 

I see nothing wrong with the lebensohl bid, given North is a passed hand. 3♣ looks to be a big underbid; I would have broken the lebensohl transfer and just bid 3NT. Having not broken the transfer, 3♦ should be a signoff, so 5♣ is simply undefined - you risk anything happening when you make undefined bids.

 

GIB is in general horrible when it comes to offshape doubles, though I'd say the fault lies with you here.

[Stephen Tu]

I see nothing wrong with the lebensohl bid, given North is a passed hand

What does north being a passed hand have to do with anything? You still want to distinguish between 0-7 vs 8-11 IMO.

The problem is GIB wants way too much for a positive response, like 10+ for a flat hand, where most players just need a good 8. One of my complaints outstanding for many many years now. I'd prefer they fix lebensohl than do away with it. (and fix double + bid with GOSH hands for that matter)

 

I think you've confused situation where lebensohl bidder is passed hand vs when *doubler* is passed hand, where perhaps 2nt should mean something else.

 

 

OP should overcall 2s with 3nt IMO; doubling is way too dangerous with short hearts, as you may find yourself at 4h on 2nd round when 3nt was the last making game. After doubling, you got away with it and found a 2nd chance, should bid 3nt then, but that would show a different hand type. 3c might have found partner with 4 clubs

and partner passing this.

Slam -- seems slightly odds against? Need DK onside.

 

[johnu]

I have seen the robots get confused by Lebensohl before, but Robot bids 5 Diamonds.

I believe bidding a bad or mediocre 4 card suit instead of passing when partner shows a strong independent suit is Standard GIB.

 

As an observation about your bidding, you should never make off shape takeout doubles playing with GIB. GIB has no concept of what it is supposed to do if you subsequently bid your long suit. With the South hand, I would have bid 3NT over 2♠.