http://bridgewinners...in-a-gcc-event/
on Bridgewinners, it may not be generally known among ACBL members that the scheme
1C-?:
1D = 4+ S
1H = 4+ H
1S = ART GF
1N = nat., NF,
which enables the partnerhip to play something like T-Walsh when Responder has spades, is actually GCC legal. But a comment by Mike Bell (MickyB) points to an even more exciting possibilty: a full-fledged GCC legal T-Walsh substitute. I believe the real idea behind his comment* is that if Responder has some conventional way of dealing with Flannery hands with less than GF values**, then there's no compelling reason why Opener's 1S rebid should promise 4+ S***, so 1S may as well be used as "transfer acceptance" similar to 1M over 1C-1M-1 in T-Walsh. Of course, there's no transfer involved here unless one thinks of 1H as a transfer to the major Responder hasn't promised. (Same with the spade-showing 1D response.)
By combining dloeb's scheme with MickyB's idea, one could play
1C-1OM-1****; ?
1OM: corresponds to 1M over 1C-1M-1 in T-Walsh.
1S = 4+ H
1S(M=S): corresponds to 1S over 1C-1D in the emulated T-Walsh style, but now with 4+ H instead of 4+ S [corrected stupid error 5th August: '1S(M=S)' was just '1S']1N: corresponds to 1N over 1C-1M-1 in T-Walsh [corrected 3rd August ('1C-1M-1' was '1C-1D')]
2C+: obvious stuff, but depending on the emulated T-Walsh style
But notice that, unlike in T-Walsh, Opener's 1OM/1S rebids are now not easily passable*****, and this could potentially be a huge problem (for more than one reason). But here are three ways to go about it, corresponding to different restrictions one might want to put on Responder's ability to respond 1D or 1H on "air" (as is common when playing T-Walsh).
a) [restrictions on both 1D and 1H] Responder will always have something resembling an inital positive response when he makes his forced rebid, so continuations, apart from the now "impossible" sequence 1C-1OM-1; 1OM/1S-P, may be roughly as in the T-Walsh style one wants to emulate.
b) [restriction on 1H only] Responder is allowed to pass 1C-1D; 1H/1S because of the following variation of the above scheme:
1C-1OM-1; ?:
1H = 4+ H, NF
1S: corresponds to 1M over 1C-1M-1 in T-Walsh, but denies 3-S4+H if M=S
1N+: as above
Continuations, apart from the now "impossible" sequence 1C-1H; 1S-P, may again be more or less as in the emulated T-Walsh style.
c) [no restrictions] Responder cannot easily pass Opener's rebid, so the continuations have to reflect this. E.g.:
1C-1OM-1; 1OM-?:
1S = 4+ H, as above
1N: as in T-Walsh, but could be extremly weak. (Conventional follow-ups may be necessary, depending on the emulated T-Walsh style.)
2C/2H+ = standard XYZ
2D = subminimum, 5+ M******
Any comments?
* "Would 1C:1S as 5H4S be allowed? This would free up 1C:1H,1S to be artificial."
** To be GCC legal, a two-level response (not 1S) has to be used as Flannery, though. An interesting alternative, but which effectively takes the Walsh out of T-Walsh, is to respond 1D, canapé-style, with 4S5+H.
*** Well, Opener may now have to rebid 2C with 4135/4045, depending on the emulated T-Walsh style. But this is the kind of problem that standard or T-Walsh player have with 1435/0445 over 1C-1S and 1C-1H, respectively, but which disappears when the response with 4+ S is 1D instead of 1H or 1S.
**** Yes, the notation '1OM-1' suggests that we may continue to view the 1D and 1H responses as transfers to the other major (=OM), the major Responder doesn't necessarily have. This is convenient when making comparisons with T-Walsh.
***** The same is true of the sequence 1C-1D; 1H-1S, but that seems like a tiny problem in comparison, so I'll ignore it.
****** This is the easiest, assuming Responder would always replay 1S (ART GF) to 1C with 4+ M and GF values. A more advanced version would allow Responder to bid again over 1C-1OM-1; 1OM-2D; 2M(= to play, assuming Responder has subminimal values) on some hands with GF values.