[Vampyr]

I am interested in the treatment in which 1M-2♣ is an artificial game force. Can anyone advise me about continuations, and also which GF hands are excluded from the 2♣ response and generally a sensible way to play this convention. Thanks.

[antonylee]

There's a pretty decent writeup by Andrew Gumperz on Bridge Winners.

Here is what I play, it works reasonably well:

1M...
... 2C = NAT or BAL GF, does not deny 4S over 1H (but denies 5S)
... 2other = GF, usually at least HTxxx (or possibly HHHx)

1M-2C... (writing shapes for 1S opening but you get the idea)
... 2D = 5(332) 12-14 or 18-19
... 2M = M+D
... 2oM = M+oM; 1H-2C-2S does not show extras (because 2N=6M, you run into issues with 4S-6H hands otherwise)
... 2N = 6M (we also play other 1M-2below auctions)
... 3C = 5224 exactly
... 3other = SPL, typically 5(31)4
... 3M = self-sufficient suit

1M-2C; 2D...
... 2oM = "4SF", typically not fit and lacking some stopper (now check for stoppers)
... 2M = 3crd BAL GF raise, typically not a real club suit
... 2N = NAT BAL no fit, stoppers (now bid values if extras)
... 3m = NAT
... 3M = "picture jump", raise with real club suit

1M-2C; 2D-2M...
... 2N = suggests 3N, typically poor trumps (e.g. Jxxxx AJx Kx KJx) -- responder can check for stoppers.
... others = NAT

I think being able to confidently diagnose whether to play in 3N instead of 4M is a pretty big gain, more than the inference that 2/1 in another suit shows a real suit.

[Zelandakh]

If you interested in this direction, you might also consider the baby brother in which step 1 (1♠ or 1NT) shows an invite or better. That means you are able to limit Opener's hand slightly before getting into the meat of the relays and usually also handles invitational hands slightly better (depending on the 2♣ version being used). The main downside is not establishing the game force immediately.

Either way, the first decision is deciding whether you want to structure the follow-ups according to hand types, as here, or move over to a system of relays from the symmetric family. My own method is of the latter type but due to the structure of the bidding system and the use of the INV+ relay method there are fewer hand types to worry about. 2♣ as a GF relay comes up after a 1♥ opening (ie the auction 1♥ - 1♠; 1NT - 2♣) but here it is known that Opener does not have 4 spades or a balanced hand, giving:-

2♦ = 4+ clubs
2♥ = one-suited, 6+ hearts
2♠ = 5+ diamonds
2NT = 5 hearts, 4 diamonds
3♣ = 0643 or 1642
3♦ = 2641
3♥ = 3640
3♠+ = 7+ hearts, 4 diamonds

Obviously your relays would need to be at sym+1 if you also had to include the other hand types. As I recall straube was using such a method at one time so perhaps he has some notes on the main case that might be of use to you.

[Vampyr]

antonylee, on 2015-December-03, 00:06, said:

There's a pretty decent writeup by Andrew Gumperz on Bridge Winners.

Here is what I play, it works reasonably well:

1M...
... 2C = NAT or BAL GF, does not deny 4S over 1H (but denies 5S)
... 2other = GF, usually at least HTxxx (or possibly HHHx)

Zelandakh, on 2015-December-03, 13:08, said:

If you interested in this direction, you might also consider the baby brother in which step 1 (1♠ or 1NT) shows an invite or better.

Thanks. I am looking for a scheme where other 2/1 bids are not necessarily GF or even NOT GF, and without a forcing 1NT response.

[Zelandakh]

Vampyr, on 2015-December-03, 17:12, said:

Thanks. I am looking for a scheme where other 2/1 bids are not necessarily GF or even NOT GF, and without a forcing 1NT response.

Well that is the other side of the INV+ relay method - all of the other responses below 2M are weak. In the case of a 1♠ opening 2♣, 2♦ and 2♥ are weak and natural; for the 1♥ opening the 2m responses remain the same but 1NT becomes the response with a weak hand and spades. Finally, my playtesting revealed that it is generally better for Responder (unless very distributional) to bid suits up the line on such weak hands even if that means canapé. That in turn means that the most expensive weak response (2♦ or 2♥) shows a 5th card in the suit but it also means, for example, responding 2m over 1♠ with a 5♥4m hand, which seems rather unintuitive at first glance. Obviously not necessary but worth baring in mind if you do eventually settle on such a scheme.