[lycier]

---

After 4♣ , south has no way to raise partner's suit to 4♦ because 4♦ will show 25+TPs.

---

After 4♣ , south has no way to raise partner's suit to 5♦ because 5♦ will show 29-30TPs.


For Gib CC, it normally goes :

---

Obviously, south pass is not correct.

[Bbradley62]

Variation on a theme of probably the most reported problem with GIB: he doesn't know how to bid in competitive auctions. Here, GIB thinks that bidding over 4♣ means "I can make this contract even if you have xxx, xxx, xxxx, xxx."

[lycier]

Bbradley62, on 2016-May-10, 18:48, said:

Variation on a theme of probably the most reported problem with GIB: he doesn't know how to bid in competitive auctions. Here, GIB thinks that bidding over 4♣ means "I can make this contract even if you have xxx, xxx, xxxx, xxx."

This is a technical difficulty which might cause a huge range to guess, so it is prone to disasters

[helene_t]

Yeah this is an annoying problem that comes up very often. It is probably not so easy to formalize sensible rules without having to code it seperately for thousands of different auctions. I would like to see a general clause that banned the "futile Willy syndrome" as illustrated with this hand, i.e. that there is no way to end in 5♦. But I suspect the way GIBs bidding system is formalized does not allow for such generic clauses.

[lycier]

Preemptive and its following Gib CC is a important part of the bridge bidding system, very large and complex for sure.
Fred and Jdonn, they are decent experts, after opp's preemptive at three level, it is very easy for them to make its following Gib CC in detailed, but I guess it is very very tough for the Gib programming because this requires the establishment of hundreds of thousands of rules at least.

[Stephen Tu]

Gib has a lot of basic rules saying that it needs x points to bid to some level expecting to make. What it needs is additional rules following somewhat human practices:
- after opposing preempt auction, assume partner has like around a 7 count, so decrease strength for bidding to a particular level accordingly.
- if competing over opponent's bid, especially their game bid, might be bidding as two-way shot (either makes, or is good sac), so again decrease minimums for competing by some amount of TP (5?). But don't make competing mandatory with that level of TP, those kind of things should be done by simulation, we want them competing with high ODR, shape not necessarily large # HCP and passing/doubling with defensive tricks, simulation should uncover whether competing is percentage or not.

[johnu]

Stephen Tu, on 2016-May-12, 13:58, said:

- after opposing preempt auction, assume partner has like around a 7 count, so decrease strength for bidding to a particular level accordingly.

I'm surprised this wasn't a fundamental piece of the initial programming, but clearly it is not after seeing hand after hand where the GIB description shows a hand with 25-30 points