[Zelandakh]

phoenix214, on 2016-July-30, 06:58, said:

But on average id assume partner has 12-14 balance,

There is no need to assume. The description tells us that Opener has 12-13. In this version of NMF, where Opener shows min/max directly on their rebid, invites are typically off so I would expect 3♠ to be slam interest. That makes it the obvious choice on this hand. It would be good if someone with access to GIB could check the meaning and report back.

[masse24]

miamijd, on 2016-July-30, 21:00, said:

1. If you play "standard" NMF, then 2S does NOT establish a game force. It shows 12-13 and 3 spades. With 14 and 3 spades, partner skips to 3S (forcing).

2. That means that unless you have agreed otherwise, 3s is NOT FORCING. It is an invite. I don't think that's what you want to do with this hand. If you don't believe me, perhaps you will believe Larry Cohen:

https://www.larryco....nter/detail/108

With all due respect to Mr. Cohen (and your detailed analysis) we'll have to agree to disagree. Cohen's version does not make the distinction between a "minimum" (12-13 and 3 ♠) and a "maximum" (14 and 3 ♠) hand. Both ranges are bundled into the 2 ♠ response to NMF. Therefore, it logically follows that an invite to ask opener "which do you have?" is required.

However, your description (and that in the OP) made the distinction between a "minimum" 12-13 and a "maximum" 14 opening hand. You even stated it was "standard." I agree. So, if opener, in response to NMF, shows the lower range of 12-13 with 2♠, there is no need for an invite. Again, it logically follows that a subsequent 3♠ call by responder is a GF. If opener's third bid in response to NMF is at the two-level or three-level based on strength then I am sure that Mr. Cohen would agree with this logic.

I see others have made the same observation.

My earlier suggestion (upthread) to play 3♠ as suit agreement and slam-seeking was based on this logic, that 3 ♠ as an invite when 2♠ shows 12-13 is superfluous.

Is NMF best? Heck no! We're in complete agreement there.