[Stefan_O]

I've seen Gib mostly plays artificial 4sf.
But not in some sequences.
Just had
1D-2C-2H-2S
described as 4+sp.
What's the rule/logic when 4sf applies or not?

[steve2005]

Anyone know if 1♦-2♣ is GF?
If so that might explain why.

[manudude03]

1D-2C is not GF in the GiB system, however 1D-2C-2H is a reverse and therefore game forcing which might explain why 2S is not 4th suit forcing.

[1eyedjack]

Even if you are in a GF situation it does seem something of a waste to use a low level bid of 2S to investigate a very rare fit.

That said, we are only concerned with what is standard, here, and whatever I feel about waste, if you are (and I think you are) in a GF scenario already, then the standard is for 2S to be natural.

[iandayre]

It used to be true that 1D-2C was not a game force, but I believe that has been changed. Which would mean that since game is already forced, 2S could be natural. Also, 2H is no longer a reverse, just a natural bid.

It's true that under the old way, 2H was a GF reverse, so 2S again could be natural.

[smerriman]

iandayre, on 2016-November-26, 14:26, said:

It used to be true that 1D-2C was not a game force, but I believe that has been changed.

Nope: http://www.bridgebas...t-bidding-hole/

[johnu]

manudude03, on 2016-November-26, 12:55, said:

... 1D-2C-2H is a reverse and therefore game forcing

By definition, 2♥ is a reverse. Whether it is game forcing is a matter of agreement.

[Bbradley62]

johnu, on 2016-November-27, 14:43, said:

By definition, 2♥ is a reverse. Whether it is game forcing is a matter of agreement.

If responder has shown 10+ (if 1♦-2♣ is not game force), reverse should always be game force. Not so if responder has only shown minimum response (1♣-1♠-2♦).

[johnu]

Bbradley62, on 2016-November-27, 15:07, said:

If responder has shown 10+ (if 1♦-2♣ is not game force), reverse should always be game force. Not so if responder has only shown minimum response (1♣-1♠-2♦).

If 2♣ is not a game force, and by agreement, 2♥ does not show extras, then why should it be a game force?

[Bbradley62]

johnu, on 2016-November-27, 16:19, said:

If... by agreement, 2♥ does not show extras...

then we would be having this conversation in a different forum. Here, we are discussing bidding with GIB, in a 2/1 environment, with no such non-standard agreement existing.

[iandayre]

smerriman, on 2016-November-26, 17:29, said:

Nope: http://ww

w.bridgebase.com/forums/topic/74820-another-clearcut-bidding-hole/

That hand supports my position. 2C is clearly stated to be forcing to 3NT. That did not used to be part of the definition. The fact that GIB passed 3C is a separate issue. 2C is forcing to game.

Regarding opener's major suit rebid after 1D-2C. In the Max Hardy version of 2/1 that I learned many years ago, 2M simply showed a suit. He recommended that 2M DENIED a good 5 card or longer D suit, in effect an anti-reverse. GIB's 2/1 is very similar to Max's methods in many ways. Now that 1D/2C is forcing to 3NT, I believe I have recently seen the 2M rebid described as above, at least about not promising extras. Someone should post the hand with description the next time that auction comes up.

[smerriman]

iandayre, on 2016-November-28, 13:20, said:

That hand supports my position. 2C is clearly stated to be forcing to 3NT. That did not used to be part of the definition. The fact that GIB passed 3C is a separate issue. 2C is forcing to game.

The concensus there was that it was the description of 2♣ that was wrong; Gib doesn't treat it as forcing to game (the system notes agree).