[straube]

After 1C (strong) 1N (5-9 with 5H, 0-3S, 0-4C) 2D (minimum, 5+S, 2H)

responder has the following rebids

2H-to play
2S-to play
2N-GI, possibly 2 spades
3C-artificial GF (can't have 5 clubs)
3D-5D, GF
3H-inv
3S-inv
3N-to play
4M-to play

We need an artificial GF (I think) primarily to check for a 6-2 spade fit and otherwise to allow opener to play 3N.

The problem with this structure is that it wrongsides major suit contracts. This can't be helped at the 2-level.
Transfers would be easy to add for the 4-level. How could we use transfers at the 3-level?

3C-transfer?
3D-transfer
3H-transfer
3S-2S, COG?
3N-0-1S?

Anything better?

[nullve]

Why not play 2N as ART GF?

[straube]

nullve, on 2016-May-31, 08:31, said:

Why not play 2N as ART GF?

Well we could, but it's useful as invitational. Our general rule is that 2N is misfitting (to play) unless we are removing from a known 5-2 fit or 6-? contract in which case it is invitational.

[awm]

I don't think you need responder to invite without extra shape in this auction. He has basically already invited by showing 5+ points opposite a strong club. If you really need to further refine the 5-7 range, opener can ask. So you can do something like:

2♥ = 5-7 less than two spades
2♠ = 5-7 two spades
2NT = GF not 5/5, not 6♥, not 3♠
3♣ = GF 6+♥
3♦ = GF 5/5
3♥ = 5-7 at least six good hearts
3♠ = 3♠ but very minimum
3NT = 3♠-5♥-(32) GF
4m = shortness with 3♠

After 1♣-1NT-2♦-2M, responder is limited to 5-7 and opener has 16-18 (maybe 19? but not 20, which would clearly GF). If opener has a very good 18 (or 19?) and wants to be in game opposite 6+ to 7 he can take another call here (usually 2NT, but other natural calls are okay on shapely hands). This changes the hands where you end up higher than 2M (instead of responder 7 and opener 16, you have responder 5 and opener 18) but it seems likely to work out okay.

[awm]

Hmm another sort of odd theoretical point:

Suppose that in general you have two limited hands where game is in the picture. You need to get to game when both hands are maximum, but you want to avoid landing in a declined invitation (which puts you a level higher, or in a slightly worse strain, or something). Who should invite when they are max for the range?

In general the more skewed point totals are less likely. So for example 18-5 is less common than 16-7, which is less common than 14-9, etc. This being the case, it is better to let the stronger hand make the decision to invite when he is at the top of this range. This is because the weaker hand is more likely to be at the top of his range than the stronger hand, and therefore when the stronger hand invites, you will invite less often (but still reach the same games assuming you need both to be max for game to be on).

[straube]

That's an interesting point.

I like your structure and I take nullve's and your point about 2N not being needed as invitational. Maybe...

2N-invitational+ hearts
3C-invitational+ diamonds
3D-artificial GF, 2 spades
3H-invitational+ spades
3S-artificial GF, 0-1 spades

Idk. Rightsiding is such a frequent issue and diamonds and invites to 3N haven't been. Very frequent 2D-3H and 2D-4H auctions.