[mikeh]

DavidKok, on 2025-August-24, 10:02, said:

XYNT already has the ability to stop in 2♦ on 1m-1X; 1NT by using the 2♣ puppet and passing. The main advantage I see of using 2♦ as weak natural NF is that opener might pull to the Moysian if the number of cards is disappointing, but this would imply that opener knows the degree of fit better than responder. In practice I think there's no gain here.

If responder is a passed hand, then we play that after 1x 1M 1N, 2D is natural, weak, but promises 5M. This allows opener to bid 2M with 3 and pass otherwise. Responder can remove that option by bidding 2C over 1N, puppeting to 2D.

[P_Marlowe]

JeffMorrow, on 2025-August-22, 17:34, said:

<snip>

Partner’s 1N promises in principle no more than 14 HCP, but I’d be neither surprised nor chagrined to find it was 15 with no intermediates or 3=3=3=4 distribution because my partner has good sense.

Players upgrade into an NT opening bid frequently, but rarely if ever do they downgrade out of a NT opening.
The simple reason: Usually your system after a 1NT is better than after any other opening, it is pretty descriptive,
and the HCP count is pretty good at evaluating balanced hands.

What do to do with a hand with a 5 card major below opening strength is ..., a simple sensible approach is to always
go for the major, obv. being max. and holding a 5332 may be a reason to stick with 1NT, but beside that go for the major.

[mycroft]

Here I am, the one-trick pony.

The answer to this depends on your agreement with partner about what hands will bid 1NT. Me, I bid 2♠ every day of the week; the 5-2 is going to take more spade tricks in trumps (even as ruffs) than in NT almost always.

There are those who believe "partner has the spades, I don't have to worry about them" and bid 1NT on 1444s and the like (I guess here 1435s). Those tend *not to* play two tricks better in spades than in NT. They also tend to lead to arguments after, no matter what you do with this hand. Having said that, not bidding 1NT with a minimum 1435 means you have to lie a different way (probably 2♣, but sometimes "pass" instead of 1♣), so, swings and roundabouts. Discuss with partner.

What about medium semi-balanced hands with a small singleton spade? could partner have 15-17 as well as the minimums?

Also, how often does your partnership raise on 3 here? with, say, a 3145 or 3415? Or maybe even 3424 and ♦73? The benefit of rebidding 2♠ is not only that the 5-2 often plays same (i.e. one trick more) or better than 1NT, but that partner might have 3 and spades are even easier. If you're "guaranteed" to be in a 5-2 (or partner's only going to have 4333 or a doubleton Kx or Ax) then the weighting pushes more to "hope to take the same tricks in NT". Enough? I don't know.

But there's no universal answer here; because there's no universal answer to "what hands rebid 1NT". And it's *very* likely that if you haven't discussed this with partner, they have a different opinion than you do.