smerriman, on 2020-October-21, 16:34, said:
The NMF part was referring to a 2♣ bid, not a 3♣ bid. The key is that 2♦ is a non-forcing bid that could be passed - in fact, swap its third spade for a diamond and it will - so you're never going to be able to force after that. Rebidding diamonds shows extra length, but not extra strength that you've already denied.
Noted, and probably I should have, in spite of my very strong expectations that GIB would misrepresent something else later in the auction. I'm not sure how I can show a good second suit (specifically diamonds) if I've already bid 2C NMF and GIB has re-bid hearts, possibly showing 5 weakish cards in my shortest suit. At some point, I'm going to be showing my diamond length and values at the 4 level in a hand that might have belonged in 3S or 3NT.
Correct me if I'm wrong, but NMF is invitational at best, much less game force (opening quality hand opposite an opener.)
I suppose I could have just ignored my 5-card spade suit and bid 2D first. At least I force game, and GIB will keep bidding hearts up to the 8 level thinking I can't really have spades .