[Bbradley62]

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I think my 3N bid should deny holding either 3 spades or 4 hearts. North might still simulate to bid 4♠ over 3N, but it should have the right parameters for the simulation.

PS: 2N should deny 6-card minors, especially in my second minor 5 cards in my unbid minor. [Sorry, I need stronger reading glasses.]

This post has been edited by Bbradley62: 2011-November-15, 08:48

[cloa513]

Of course 3NT doesn't make either- isolation of dummy and repeated heart leads kill it. Why doesn't GIB bid 3♦ instead of 3♣? Is 2NT forcing to games?

[barmar]

2NT isn't forcing to game, but North's 3♣ is (GIB doesn't play Wolff Signoff, which is a convention that allows stopping on the 3 level). 3♦ by South would a rebiddable suit (a good 5-card suit).

4♠ is actually the book bid -- it prefers to play in a 7-card fit when it has a singleton (it doesn't care whether the singleton is in partner's suit or not). It does run simulations, and in some of my runs it chose to pass, and the simulations are a little less likely to pull when the singleton is in partner's suit. The simulations are also sensitive to the locations of the honors -- 3NT does much better when North has ♥Qxx rather than xxx (these are the kinds of details that are difficult to put into rules).

[Bbradley62]

barmar, on 2011-November-14, 23:24, said:

4♠ is actually the book bid -- it prefers to play in a 7-card fit when it has a singleton (it doesn't care whether the singleton is in partner's suit or not). It does run simulations, and in some of my runs it chose to pass, and the simulations are a little less likely to pull when the singleton is in partner's suit. The simulations are also sensitive to the locations of the honors -- 3NT does much better when North has ♥Qxx rather than xxx (these are the kinds of details that are difficult to put into rules).

As I hopefully made clear in my OP, I'm perfectly happy with the fact that North is simulating -- I just want him to be simulating using the appropriate limitations on South's distribuion to get more meaningful results. The description of South's 3N should be:
2-4C; 4-5D; 2-3H; 2S; 18-19 HCP, not
2-5C; 3-5D; 2-4H; 2-3S; 18-19 HCP.

[barmar]

Despite what the description said, the hands in my simulation runs all fit your expected description.

Unfortunately, the GIB bidding database is full of rules where the criteria for a bid and the description of the bid don't match. When GIB is simulating, I think it uses the criteria, not the description, when finding matching hands.

[Bbradley62]

Thanks.