[Bbradley62]

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Why does North choose diamonds over spades?

[Antrax]

Looks like the old issue where once a suit is agreed it's trumps forever. The fact 4NT is keycard for ♦ is a strong indication for that, when there's no suit agreement GIB plays 4NT as keycard for the last naturally-bid suit.
That being said, isn't it better to play in your 4-4 fit?

[1eyedjack]

6S is a slightly better contract because you are slightly less likely to sustain a D ruff before drawing trumps in 6S than to sustain a S ruff in 6D. There seems to be no other difference here. Also of course it scores better, which is a huge plus if MP (not stated either way).

[Bbradley62]

Antrax, on 2014-June-01, 21:22, said:

That being said, isn't it better to play in your 4-4 fit?

With my first three bids, I've shown at least 5 clubs, exactly (despite the description) 4 diamonds and exactly 3 spades. If my 13th card is a 6th club, North should expect to be able to ruff a heart in the short hand playing spades, which makes that better than playing in diamonds. I think it would be very difficult, looking at the North hand, to construct a South hand meeting the bidding criteria that makes 6♦ a better contract than 6♠.

PS: If the 3♦ bid is going to irrevocably set diamonds as trump, 3♠ should be a cue bid, not a length-showing bid.

PPS: Why does spade length disappear from the descriptions of North's bids, starting with 3♦?

PPPS: I suppose that if 3♦ shows 4+ diamonds and more spades than diamonds (given GIB's up-the-line style), I should just bid 4N over 3♦ and get the contract to 6♠. Or would GIB overrule me and bid 7♦?

[georgi]

Nice case.

Regarding 3♦ missing spades ( or responder first suit). It's fixed in v30 ( current one ). There was a bug which masked previously promised responder's suit. Now shows 4+ 4+ again.


Regarding blackwood.

Easy solution could be GIB just to stop in spades in case there are 8+ cards ( GIB will need to look in hand at that moment ).

If blackwood is generally over spades might be risky as responder could have just 4 spades and while opener promised just 3 ( overall 7 cards to this moment ) to be undesired contract.

So a probable improvement could be regardless the way of bidding( not only after reverse ). GIB might be improved to pick a contract after 4NT where there is higher ranked suit ( mostly major vs minor ).

Since two versions ago ( v29 and v30) partner GIB would pass such slam where there are 6+ shown cards ( could be only by opener/responder or also by both partners ).

[Bbradley62]

Several "coulds" and "mights" in that response. Does that mean you're thinking about what to do to fix this?

[georgi]

I would address this for design decision. Then a change would be applied or kept as it is