[thepossum]

Dear all

Following a few recent IMP shocks I've been analysing all sequences in a group of tables with the same hands to find out why some sequences have such massively divergent outcomes despite going via a bid with the exact same description and strength

I do not know if the issue is one of understanding the complexity/precision of certain sequences in 2/1 or how GiB has coded them. However it is clear that when bidding you cannot rely solely on bid descriptions and need to bid according to system rather than how GiB describes them

In a recent hand which makes 7D or 7NT many souths were left in 3NT and many received a jump to 6D by GiB after south's 3NT despite the description on the 3NT being identical in all the sequences.

The issue comes down to earlier bids in auctions

If you have the following sequences. North (GiB) opening the bidding, no interference EW

1. 1D-1S-2D-3N-?

2. 1D-1S-2D-3C-3D-3N-?

3. 1D-1S-2D-2H-2N-3N-?

The 3NT by south is described identically in each auction. However the first two resulted in a jump to 6D and the third resulted in a pass

North (GiB) had the following hand

---

What I am curious about from both a 2/1 and GiB perspective is why sequences 1 and 2 are so different to sequence 3

regards P

[TylerE]

GIB is bridge russian roulette. My advice to you is to forget that it exists. playing too much with GIB will ruin your actual game.

[hrothgar]

Comment 1. Stop trying to learn from GIB
Comment 2: Get a book on bidding and read it
Comment 3: None of these sequences involve 2/1 bids

With this said and done

In sequence 2, responder started by making what looked like a game try, then ignored a signoff and bid game anyway.

[thepossum]

hrothgar, on 2019-February-23, 23:48, said:

Comment 1. Stop trying to learn from GIB
Comment 2: Get a book on bidding and read it
Comment 3: None of these sequences involve 2/1 bids

With this said and done

In sequence 2, responder started by making what looked like a game try, then ignored a signoff and bid game anyway.

Response 1. I'm not trying to learn from GiB. Ive been playing a long time and am trying to apply 2/1 by playing GiB which allegedly is its system
Response 2. Ive been reading books on bridge bidding and play and playing for 40+ years since I was teenager/young adult
Response 3. They are 2/1 or standard bids since that is the system we and GiB are using

regards P

[gordontd]

thepossum, on 2019-February-24, 00:05, said:

Response 1. I'm not trying to learn from GiB. Ive been playing a long time and am trying to apply 2/1 by playing GiB which allegedly is its system
Response 2. Ive been reading books on bridge bidding and play and playing for 40+ years since I was teenager/young adult
Response 3. They are 2/1 or standard bids since that is the system we and GiB are using

regards P

Comment 4. Stop asking questions here if you are unwilling to consider that the answers may have value.

[thepossum]

gordontd, on 2019-February-24, 01:52, said:

Comment 4. Stop asking questions here if you are unwilling to consider that the answers may have value.

Here we go again. The usual suspects. The three comments against me were of no help, just an attack nd you as usual just join the attack

Nobody has yet made a useful comment (except part of Hrothgars if you ignore the three attacking comments)

[hrothgar]

thepossum, on 2019-February-24, 00:05, said:

Response 1. I'm not trying to learn from GiB. Ive been playing a long time and am trying to apply 2/1 by playing GiB which allegedly is its system
Response 2. Ive been reading books on bridge bidding and play and playing for 40+ years since I was teenager/young adult
Response 3. They are 2/1 or standard bids since that is the system we and GiB are using

regards P

GIB makes decisions based on random simulations.
Even relatively small changes in the auction can have dramatic impacts on the bidding choices that GIB makes

In this example, auction 2 suggests that responder has extra values since responder made a superfluous game try.
(Why bid 3!C if you were planning to bid 3NT regardless)
Opener is not really captain in this auction, but the 8 card suit is an incredibly powerful holding that has not yet be shown.
Look like the simulations suggest that slam rates to have a higher expected value than pass.

I suspect that the conservative decision on board 3 happened because responder showed 5+ Spades and 4+ Hearts.
This probably impacted the expect length of responder's Diamond holding sufficiently that bidding slam not longer had a better expected value that pass.

However, I am just guessing because it is almost impossible to diagnose why GIB does what it does....

If you are really interested, your best option is probably to create a script that will deal 1000 or so hands consistent with the auction so far and see what the different hands look like.

[Stephen Tu]

hrothgar, on 2019-February-24, 04:47, said:

In this example, auction 2 suggests that responder has extra values since responder made a superfluous game try.
(Why bid 3!C if you were planning to bid 3NT regardless)

I disagree with your interpretation. I don't think 3c is "game try". 3rd suit at 3 level is GF normally. Invites bid 2nt or 3d or 3s with normal agreements. Perhaps responder is probing for 3 cd spade support, and bids 3c rather than 2h because 5224 or 5314 or 5215, 2h ostensibly shows hearts. Was planning on playing 4s or 3nt.

[hrothgar]

Stephen Tu, on 2019-February-24, 05:16, said:

I disagree with your interpretation. I don't think 3c is "game try". 3rd suit at 3 level is GF normally. Invites bid 2nt or 3d or 3s with normal agreements. Perhaps responder is probing for 3 cd spade support, and bids 3c rather than 2h because 5224 or 5314 or 5215, 2h ostensibly shows hearts. Was planning on playing 4s or 3nt.

Sorry. Stephen is correct.
Brain fart by me.

(Sitting in the Casablanca airport, working on way too little sleep with a truly screwed up GI tract)

[HardVector]

Basically, what everyone is saying is that what GIB does is NOT cooperative bridge. It's random gobeldegook. Sometimes it's ok, most of the time it's incomprehensible. If it's your intention to gain notoriety by being the best GIB partner around, then stop trying to play actual, cooperative bridge and try and figure out the algorithms that the program run on.