Minor transfer over 1N

[thorvald]

I have noticed, that when the Bot transfers to 3 minor after a 1N opening it often has, what I call an invitational hand, but the explanation just states 6+ card in the minor,

 

So I am often (not always) losing Imps when opener bids 3N like here:

 

[hv=url=https://www.bridgebase.com/tools/handviewer.html?bbo=y&lin=pn%7CHuman%2CRobot%2CRobot%2CRobot%7Cst%7C%7Cmd%7C1SAQ4H973DKT97CAQ6%2CSJT862HAT6DJ4CT73%2CS953HQ4DQ6CKJ9842%2CSK7HKJ852DA8532C5%7Csv%7CN%7Cah%7CBoard%2015%7Cmb%7C1N%7Can%7Cnotrump%20opener.%20Could%20have%205M.%20--%202-5%20%21C%3B%202-5%20%21D%3B%202-5%20%21H%3B%202-5%20%21S%3B%2015-17%20HCP%3B%2018-%20total%20points%7Cmb%7CP%7Cmb%7C2N%21%7Can%7CMinor%20transfer%20--%206%2B%20%21C%7Cmb%7CP%7Cmb%7C3N%7Can%7C2-5%20%21C%3B%202-5%20%21D%3B%202-5%20%21H%3B%202-5%20%21S%3B%2017-%20HCP%3B%2018%20total%20points%7Cmb%7CP%7Cmb%7CP%7Cmb%7CP%7Cpc%7CSJ%7Cpc%7CS3%7Cpc%7CSK%7Cpc%7CSA%7Cpc%7CCA%7Cpc%7CC3%7Cpc%7CC2%7Cpc%7CC5%7Cpc%7CCQ%7Cpc%7CC7%7Cpc%7CC4%7Cpc%7CH2%7Cpc%7CC6%7Cpc%7CCT%7Cpc%7CCK%7Cpc%7CH8%7Cpc%7CCJ%7Cpc%7CD2%7Cpc%7CD7%7Cpc%7CH6%7Cpc%7CC9%7Cpc%7CD8%7Cpc%7CD9%7Cpc%7CD4%7Cpc%7CC8%7Cpc%7CH5%7Cpc%7CS4%7Cpc%7CHT%7Cpc%7CD6%7Cpc%7CD5%7Cpc%7CDK%7Cpc%7CDJ%7Cpc%7CSQ%7Cpc%7CS8%7Cpc%7CS5%7Cpc%7CS7%7Cmc%7C9%7C]399|300[/hv]

 

The defense is difficult, but after the lead only chance is that partner has Axx in ♥, as declarer has 6♣+2♠, and always will make if he has ♥A - the bots two first discards was ♥.

[thepossum]

I find the Bot's minor transfer rather disappointing and often notice a play for 3NT :(

 

It's rarely weak like many of its preempts

 

I reckon I accept it around 50% of the time to increase my chances :)

 

Would be interested in its stats but confirmation bias suggests there is always a top on 3NT

[helene_t]

Maybe what is going on is: You showed 18 total points while you have 15. GIB trusts your bidding so W can't have ♥A.

[thorvald]

Maybe what is going on is: You showed 18 total points while you have 15. GIB trusts your bidding so W can't have ♥A.

 

1N is limited to 17 HCP, so ♥E could be at West

[smerriman]

1N is limited to 17 HCP, so ♥E could be at West

But the generally undefined / impossible 3N shows 25+ HCP (game opposite partner's 0); the text description is just a rough attempt at resolving the contradiction. All simulated hands have South holding the ace as Helene suggested.

 

The bidding is more a system failure than anything else; GIB has no way of inviting with this hand, so the transfer is used for anything with 0-8 HCP. Much simpler when you can superaccept.

[helene_t]

1N is limited to 17 HCP, so ♥E could be at West

It said 18 total points, if that translates to 17 HCP then there is at most 4 points left to West, and West already showed ♠J.

 

Are there any hands with 18 total points and 16 HCP that would open 1NT? I thought total points just add one point for a 5-card suit but maybe I am wrong about this.

[thorvald]

But the generally undefined / impossible 3N shows 25+ HCP (game opposite partner's 0); the text description is just a rough attempt at resolving the contradiction. All simulated hands have South holding the ace as Helene suggested.

 

The bidding is more a system failure than anything else; GIB has no way of inviting with this hand, so the transfer is used for anything with 0-8 HCP. Much simpler when you can superaccept.

 

So even though a bid is limited to 15-17 HCP from a 1N bid, the simulation does not use that ? But instead looks at the undefined bid and assumes 25+ HCP. Very interesting error in GIB's logic.

[helene_t]

So even though a bid is limited to 15-17 HCP from a 1N bid, the simulation does not use that ? But instead looks at the undefined bid and assumes 25+ HCP. Very interesting error in GIB's logic.

I don't think it is reasonable to expect GIB to make reasonable inference from mutually contradicting bids. You also sometimes see bids explained as a 5-5-4-0 shape (i.e. 14 cards) in an attempt to reconcile contradictions.

 

If GIB would just interpret all my non-self-contradicting bids correctly I would be very happy :)

[smerriman]

So even though a bid is limited to 15-17 HCP from a 1N bid, the simulation does not use that ? But instead looks at the undefined bid and assumes 25+ HCP. Very interesting error in GIB's logic.

No, hands still match the 1NT opener; I'm just saying that you can't look at one specific bid and argue that GIB should completely ignore another one, or that anything is really an 'error' when you've contradicted yourself.

 

I don't know how GIB resolves contradictions like this; but the variance that GIB has built in for dealing hands 'close' to what you have seems to disappear, because everything is too far away from what you've shown. So all dealt hands end up as extreme maximums to get as close as possible. As Helene mentioned, all 17 counts include the Ace.

 

Might look further at this in part 2 of my reverse-engineering GIB post, if I ever around to publishing part 1 after many months of planning it..