[p_t_red]

This has bitten me several times already. In the 2/1 Game Force system I play, 2 clubs over 1 diamond is forcing to game. Robots keep passing me on the second round of bidding however. I finally found this tidbit in the GIB card:
"2C response is forcing to one round, but not game force.".
Nice to know that finally, but it would be nicer if the bid tip when you hover over the 2 club bid said that
instead of "Forcing two over one -- 11+ HCP; Biddable C".
Also, the card should have some indication of 2/1 only over the majors under "General Approach".

[Vampyr]

p_t_red, on 2013-March-01, 14:45, said:

"Forcing two over one -- 11+ HCP; Biddable C".

There was a thread about this recently. In general bridge parlance, "forcing" means forcing for one round.

[mycroft]

Unfortunately, that's what 2/1 game force means - over a major.

Originally it was major to minor only; 1♠-2♥ was also only a 1R Force, showing 10+ and 5+hearts. Very few people play that any more.

However, the minors are a different story; for some reason people in my area too want 1♦-2♣ to be a GF (as well as 1♦-2♦) meaning they have no bid with 6 diamonds and 2 points, or a 3=2=4=4 6 count they don't want to bid 1NT on - or, of course, a 3=1=4=5 or 3=1=3=6 or 2=2=3=6 10, 11 count (if you would promote that into a GF, drop it a point or so until it fits).

All I'm saying here is that the fact that GIB plays an older, (to my mind saner) 2/1 system that meets the traditional definitions is unsurprising. It's unfortunate it caught the OP.

[Siegmund]

I am from the same camp as mycroft: "2/1" traditionally applied only over the majors, and playing 1D-2C was a common newbie error -- which has become an occasional deliberate system choice recently.

1D-2C GF is recommended by the Grant and Rodwell book - likely as a simplification to save them from having to teach a special set of rebids over 1D-2C - but not in any of the other standard 2/1 references that I recall.

[Antrax]

The Lawrence 2/1 CD discusses both treatments. If memory serves it recommends the GF approach.

[steve2005]

i think if you play 1♦-2♣ GF you really need 1♦-3♣ as INV with 6♣ rather than usual weak jump-shift