[jillybean]

For those playing 4cM's

2C : 2D waiting
2M

What does your 2M bid show?

[Tramticket]

I don't think that this sequence is dependent on your one-level system.

The sequence promises a five-card suit. With two four-card suits you are balanced. Very strong 4441 hands are awkward. They are awkward in any system.

[Stephen Tu]

4cM 1 level openers don't have any effect on this sequence. It would be extremely weird not to have 2M show 5+ if natural (2H often played as natural or super strong balanced, aka Kokish aka Birthright). Likely unworkable otherwise, if 2M only promised 4 you'd have a ton of trouble on the way more common 6+ and 5+ 2c openers.

Hands with 4cM that could be opened 2c:
- balanced/semi-balanced hands. These should all rebid some number of NT or go through Kokish.
- 4M/long clubs. Just rebid clubs, use 3D by responder as an ambiguous probe to find 4cM if any.
- 4M/long diamonds. It's reasonably popular to use 2c-2d-3M as 4M long diamonds, giving up the single suited set trump/demand cue meaning. Otherwise it's rebid diamonds and tough to cater to finding the 4-4s.
- 3 suiters ... OK these are genuinely a problem. No naturalish system that doesn't have a "strong Roman" opener (sometimes combined with a multi-2d) handles these great; strong Roman is usually sacrificed just because they are so rare compared to other uses of 2 bids. With 3-suiters, you basically have a choice between open 1, hope you don't get passed out with slam on, pretend the hand is balanced (with stiff honor preferrably), or rebid a beefy 4cM and pretend it's a 5-bagger.

[Cyberyeti]

Old fashioned Acol would only show 4 with a 2M rebid, but very few people do that nowadays AKQ, AKQx, Jxxxx, A for example would rebid 2♥ although I suspect many now would choose 2N.

[jillybean]

Cyberyeti, on 2021-July-01, 01:33, said:

Old fashioned Acol would only show 4 with a 2M rebid, but very few people do that nowadays AKQ, AKQx, Jxxxx, A for example would rebid 2♥ although I suspect many now would choose 2N.

This perhaps explains it, thanks.

AK96, AKQ5, 4, KQ43

2♣ : 2♦
2♥

[Cyberyeti]

jillybean, on 2021-July-01, 04:25, said:

This perhaps explains it, thanks.

AK96, AKQ5, 4, KQ43

2♣ : 2♦
2♥

That hand says "don't open 2♣ on a 21 count without a 5 card suit" (unless that's in your 2♣/2N range).

1♣ for me on that