[chasetb]

http://tinyurl.com/kqf72gz

I know I was light, but the opening, along with the void response to 4NT, propelled us to slam. My question is how to get GIB to try and find the cold 7♠ contract, after I show we have all 5 keycards and there's a chance of 7 because of cross-ruffing.

This isn't a problem solely of GIB, I think you would be hard-pressed to find anyone outside of experts and world class players who have a chance here of finding the Grand (or having the gall to bid it). What I'd really like to know is how the logic of GIB works. I see that holes are being plugged here and there, but at times it can still be frustrating.

[BillHiggin]

chasetb, on 2013-August-04, 10:45, said:

http://tinyurl.com/kqf72gz

I know I was light, but the opening, along with the void response to 4NT, propelled us to slam. My question is how to get GIB to try and find the cold 7♠ contract, after I show we have all 5 keycards and there's a chance of 7 because of cross-ruffing.

This isn't a problem solely of GIB, I think you would be hard-pressed to find anyone outside of experts and world class players who have a chance here of finding the Grand (or having the gall to bid it). What I'd really like to know is how the logic of GIB works. I see that holes are being plugged here and there, but at times it can still be frustrating.

Mostly speculation, with a small amount of knowledge of how GIB bids:
1) "logic" is not an appropriate word to apply to GIB bidding.
2) GIB mainly chooses bids based on tables of rules and priorities. These seem (to me) to be based on a static appraisal of strength and shape (GIB does not seem to revalue honors that most of us would revalue based on being in our long suits or not)
3) When the rules and priorities do not provide an answer, GIB generates hands based on what partner has shown and analyzes what the final contract should be based on those samples. Note that this is not going to be accurate here since GIB thinks you have 5+ spades, 11+HCP and 12-17 total points. GIB will think you have something like Kxxxx AQJx void Jxxx (for example) and that does not make a good grand slam (some of the other samples may make good grands - less heart wastage and better clubs - but GIB is unlikely to consider 7-5-0-1 as a possibility)

I will let others comment on how humans would bid this.