[MattieShoe]

I was trying to figure out the different meanings of 2NT... Not having a regular partner, 2NT seems particularly tricksy. Unusual 2NT, Jacoby 2NT, responding 2NT after a pass, 2NT overcall of 1NT (capp, DONT, etc)...

I was having a tough time figuring out how to even ask, so I'm going to list how I would interpret them, and tell me if you think I might be missing something. Ignore ACOL for now :-)

1. 2NT response to 1 of minor without previously passing
Natural (13+, balanced, unlikely to have good 4 card major)

2. 2NT response to 1 of major without previously passing
Natural (13+, balanced, unlikely to have good 4 card major)
or Jacoby 2NT (4+ card support, game force, etc)

3. 2NT response to 1 of minor having previously passed
Natural (11-12, balanced, unlikely to have good 4 card major)

4. 2NT response to 1 of major having previously passed
Natural (11-12, balanced, unlikely to have good 4 card major)

5. 2NT overcall of 1NT
Capp or DONT - Two suited in the minors, at least opening points

6. 2NT overcall of 1♣/♦/♥/♠
Unusual 2NT - Two suited in the two lowest unbid suits

7. 2NT response to 1NT
Natural - 8-9 points, balanced, likely no 4 card major
or Transfer to diamonds

8. 1♥ 2♥ P 2NT or 1♠ 2♠ P 2NT
Michaels -- requests minor

9. 2♣ P 2NT
Balanced, 8+ points

10. 1NT 2♣ P 2NT
Capp - 11+ points and support for all suits

11. 1NT 2♦ P 2NT
Capp - two suited in minors, request to bid better minor

12. 1NT 2♥/♠ P 2NT
Name long minor (may be game finding or denial of major fit)

13. 2♦ P 2♥ P 2NT
Multi 2♦ - 22-24 points and balanced

Did I miss some common conventional meanings?

Also...
What does 2NT over a weak 2 bid indicate?

Do you change the meaning of 2NT response after intervening bid? for example
1♣ 1♦ 2NT
1♦ 2♣ 2NT
1♠ 2♥ 2NT
I've been treating it as the same meaning, but guaranteeing a stopper in opponent's suit...

[TylerE]

1. 2NT response to 1 of minor without previously passing
Natural (13+, balanced, unlikely to have 4 card major)

Non-standard. SAYC says it's 13-15, although most who claim to play SAYC don't know that. Just about everyone else plays it as 11-12.

2. 2NT response to 1 of major without previously passing

Jacoby is near universal.

3. 2NT response to 1 of minor having previously passed
Natural (11-12, balanced, unlikely to have 4 card major)
The same as by an unpassed hand, but frankly not a bid I'd make very often. If you think your hand is that good, maybe you should have opened?

4. 2NT response to 1 of major having previously passed
Still Jacoby for most people.

5. 2NT overcall of 1NT

2NT does not exist in DONT.

[MattieShoe]

My mistake, 2NT is only capp, not DONT. I've never played DONT so I'm a bit fuzzy on it. :-)

Thanks for tips. :-) From my experience, Jacoby isn't universal amongst beginners, though it does seem to be for the more experienced players. That's part of why it seems so tricky for me to play with random partners of wildly different strengths when 2NT bids show up. :-)

[ArtK78]

As a matter of fact, 2NT does exist in DONT. According to Karen Walker, it is defined as follows:

2NT = Major-minor two-suiter (6-5 or better), monster hand. (This relays partner to 3C, over which opener identifies his two suits via a fairly complicated code. See the original Bridge Today article for details on these follow-up bids.)