awm, on 2011-March-08, 17:24, said:
On to your 2♦ method, the issue is that your best fit will fairly often not be in opener's major suit. If you have a big minor suit fit, finding it will lead you to a better partial and quite possibly a nice game contract that you might otherwise miss bidding 1M-2♦-2M. I've seen people play this as "any invite" (for example I think it is part of Marshall Miles' unbalanced diamond system) but it doesn't seem to me that this works too well. I'd rather play 2♦ as natural and invitational-plus, with opener rebidding 2M on non-fitting minimums. This allows you to use it sometimes as a two-card limit raise (with side diamonds), but it also helps with: (1) diamond invite hands (2) hands where you have a real diamond fit you find it rather than having to play 2M on a 5-2 (3) two-suited minor invites, which can be hard to bid in other methods (4) certain kinds of fitting slam tries where knowledge of a nice side diamond suit in dummy may be key to a slam decision.
I've just looked at a few hands (maybe 50 or so) and I looked at what a liberal use of 2D might accomplish....coupled with 1S-2H being natural invitational and nf...
2D showing always only GI with...
A) 2 spades and 3+ diamonds
B) single-suited diamonds with usually less than 2 spades. With 2 spades one might miss a 6-2 fit unless starting with 1N
C) good 5/5 minor hands
I rather liked how it worked out.
1S-2D,
.....2H-minimum, 4H
..........2S-2-fit
.....2S-minimum
..........P-to play
..........2N-?
..........3C-5/5 minors
..........3D-6D
.....2N-maximum, no 7th spade or second 5-cd suit
..........3C-5/5
..........3D-6D
..........3H-2S/4H
..........3S-2S
I also didn't notice losing a lot of superior minor suit fits. I think I lost a 4/4 diamond fit when we had only a 5-2 spade fit.
Now when responder doesn't have 2 spades and doesn't have 5 hearts, it ought to pay more to bid a quiet 1N and see if partner can rebid a suit for which we are fitting. 1S-1N would still hold promising hands....just less of them.
I'm not convinced this is right. I'm dealing with a GCC restriction that 2D can't be used artificially except for another GF (and I have one of those). Also, we have a GCC restriction that 1S-2H be natural. But it seems like 1S-2H as invitational nf is useful.