[manudude03]

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From a challenge match. Surely it can do more than bid a measly 4H after my 3C response?

[smerriman]

Basic or advanced? I don't think basic robots have anything built in which tells them how to evaluate hands opposite partner's shortage (same issue with splinters). Would hope advanced robots could figure it out though.

[Stephen Tu]

The advanced bots are also pretty hopeless in this sort of situation. Problem is all the encouraging bids are coded as showing significant extras rather than having something that says "min, but no wastage"

[Lovera]

Stephen Tu, on 2018-August-14, 05:15, said:

The problem is all the encouraging bids are coded as showing significant extras rather than having something that says "min, but no wastage"

The S hand is unbalanced and in the second range of force.(Lovera)

[nige1]

manudude03 .From a challenge match. Surely it can do more than bid a measly 4H after my 3C response?.
+++++++++++++++++++

GIB seems to cope badly with splinters.
After 1♠ - 2N - 3♣ - ??
A possible improvement might be...
-- 3♦/3♥/4♣ = CUE (could be MIN without duplication).
-- 3♠ = MIN with good trumps but without duplication or any sensible cue.
-- 3N = ART. Serious slam try (Downside. You can't suggest it as a place to play).
-- 4♦/4♥ = EXC RKC with void.
-- 4♠ = MIN with duplication.

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[Lovera]

nige1, on 2019-August-24, 03:57, said:

manudude03 .From a challenge match. Surely it can do more than bid a measly 4H after my 3C response?.
+++++++++++++++++++

GIB seems to cope badly with splinters.
After 1♠ - 2N - 3♣ - ??
A possible improvement might be...
-- 3♦/3♥/4♣ = CUE (could be MIN without duplication).
-- 3♠ = MIN with good trumps but without duplication or any sensible cue.
-- 3N = ART. Serious slam try (Downside. You can't suggest it as a place to play).
-- 4♦/4♥ = EXC RKC with void.
-- 4♠ = MIN with duplication.

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GIB seems to copy badly with splinters probably because is too wide the 3♣ range choising the minimum.

[johnu]

I can't remember other descriptions for responder's rebids. What would GIB rebid with

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after opener bids 3♣? And what do GIB's other possible rebids besides 4♥ show? Of course, opener can't see what other rebids by responder would have shown which might narrow down the 4♥ description.

In any case, this is yet another example where GIB was programmed for the 1st 2 bids (i.e. the 2NT response and opener's rebid) of a convention but further followup bids were not programmed.

[johnu]

Lovera, on 2019-August-24, 08:21, said:

GIB seems to copy badly with splinters probably because is too wide the 3♣ range choising the minimum.

The range of opener's 3♣ response to Jacoby 2NT has absolutely nothing to do with GIB's inadequate description for 4♥. Responder only has to reevaluate their hand after finding out that opener has shortness in clubs.

[Lovera]

johnu, on 2019-August-24, 13:50, said:

The range of opener's 3♣ response to Jacoby 2NT has absolutely nothing to do with GIB's inadequate description for 4♥. Responder only has to reevaluate their hand after finding out that opener has shortness in clubs.

I don 't think that knowing S has more than a minimum hand the bid ends in 4♥. The wide ranges are not usefull.

[johnu]

Lovera, on 2019-August-24, 15:11, said:

I don 't think that knowing S has more than a minimum hand the bid ends in 4♥. The wide ranges are not usefull.

One of the major points of Jacoby 2NT is to determine whether there is wasted HCP values opposite shortness. Only responder knows if there is shortage, no matter what opener's range may be. Unless responder shows wasted values in opener's short suit, opener is completely in the dark. The description of 4♥ does not help opener to make an educated bid over 4♥ in any meaningful way.

[Lovera]

johnu, on 2019-August-24, 15:47, said:

One of the major points of Jacoby 2NT is to determine whether there is wasted HCP values opposite shortness. Only responder knows if there is shortage, no matter what opener's range may be. Unless responder shows wasted values in opener's short suit, opener is completely in the dark. The description of 4♥ does not help opener to make an educated bid over 4♥ in any meaningful way.

The use of this convention usually opens the way to the cue bids for the description of the hand that the sudden jump does not allow. You should see through simulations with other bids and how GIB reacts before considering the declarative description of 4 ♥.

[Lovera]

What i mean when talking of "too wide range" is to bid instead:S 1♥ - N 2NT(Jacoby conv.), 3♥(=strong unbalanced 16-18 with a shortness)- 4♣(=cue), etc.

[johnu]

Lovera, on 2019-August-25, 07:48, said:

What i mean when talking of "too wide range" is to bid instead:S 1♥ - N 2NT(Jacoby conv.), 3♥(=strong unbalanced 16-18 with a shortness)- 4♣(=cue), etc.

I repeat, the wide range of 3♣ had nothing to do with missing a slam. GIB plays the 3♣ to Jacoby 2NT the same as tens of thousands of tournament bridge players who wouldn't have a problem with this hand.