[gwnn]

How strong is 1m-(1M)-1NT when 1m contains all strong NT's (14-16)? We play that 1NT without the interference promises an invitation opposite a strong NT, with hands too weak or too strong going through a T Walsh 1S (we also play 1S transfer to 1N when the interference is 1H). We had this come up with helene_t and needless to say one of us thought it might show an invite opposite the strong NT and the other one that it's a signoff.

[akwoo]

1) I assume you're really asking about 1m-(1♠)-1NT?

2) We really do need some information about the rest of your system over interference say something. At the very least, it matters what your free bids show.

[gwnn]

Standard stuff, forcing freebids.

[Zelandakh]

In Acol it shows 8-10, with a weaker hand and length/strength in their suit you just pass. I am not convinced that changing that to 9-11 just because the 1NT opening is a point lighter is necessarily such a great idea but if you are willing to pass with 8 you could do that of course. It certainly should not be a sign off imho.

[Stephen Tu]

I think it boils down to whether you prefer to defend 1M with 14-16 opposite 7-8 or so, or try to play 1nt. If you pass 7/8, I think 14-16 more or less has to pass without a hand suited for takeout double; you want the 1m-(1M)-p-(p); 1nt to be 17-19 I think, I doubt wider range is really playable.

Personally I am in the "non-invitational opposite str NT" camp for the direct seat 1nt. If partner doesn't have the strong NT usually he can run to 2 of some minor or 4th hand will bid something.

[helene_t]

Maybe in the context of a nebolous minor system, the simple raise should show 3+ support and values to (at least) invite opposite the strong notrump hand but to play opposite a minimum unbalanced? Then 1NT could be to play opposite 14-16.

[nullve]

I play something close to the following in 1st and 2nd seat NV:

1C = nat. or 14-19 bal.
1D = nat., unbal.

1C-(P)-?:
1M-1 = 0+, 4+ M
...1M = 3 M or 14-16 bal. or 17-19 bal. w/ 4-5 M
...1N = 17-19 bal. w/ 2-3 M
1S = "0-6 or 10+", 3-S3-H unless GF
...1N = 14-19 bal.
1N = "7-9", nat. (to play opposite 14-16 bal., FG opposite 17-19 bal.)

1C-(1H)-?:
X = 0+, 4+ S
...1S = 3 S or 14-16 bal. or 17-19 bal. w/ 4-5 S
...1N = 17-19 bal. w/ 2-3 S
1S = "0-6 or 10+", 3- S unless GF
...1N = 14-19 bal.
1N = "7-9", nat. (to play opposite 14-16 bal., FG opposite 17-19 bal.)

1C-(1S)-?:
P = 0+, 4+ H
...X = 3H or 14-16 bal. or 17-19 bal. w/ 4-5 H
...1N = 17-19 bal. w/ 2-3 H
X = "0-6 or 10+", 3- H unless GF
...1N = 14-19 bal.
1N = "7-9", nat. (to play opposite 14-16 bal., FG opposite 17-19 bal.)

Of course, some additional sci-fi stuff is needed to sort everything out, not least after 1C-(1S)-P; X, when Responder still has to bid on nothing.

[akwoo]

This is one of the issues that caused me to switch to non-forcing free bids when playing a weak NT. We found too many hands that were invitational opposite a good 16 (we played 12-14, not 11-13 - I'm assuming OPs minimum unbalanced openers are lighter than ours were also) but not strong enough to force opposite a minimum unbalanced hand.

Playing non-forcing free bids, 1N to play is very comfortable. With the invitational opposite 15-17 hand over 1♣-(1♠), you have 2♦ or 2♥ or helene_t's 2♣ with a (semi-)balanced 8 (BTW - helene - you still have the problem of what to do with an invitational hand without 3+ support).

Playing forcing free bids, I think you have to decide whether you want to give up playing 1N on some hands or having less precision in at least some of your invitational auctions. (Of course, there are drawbacks to playing non-forcing free bids as well.)

Form of scoring and vulnerability also matter (at MPs, the benefits of playing 1N vs defending 1M vary a lot from white/white to red/red), but I'm not sure you want to put that on your memory load.