[gwnn]

In this system, 1m-1M-2M promises a single raise of 4 cards or a minimum unbalanced hand with 3 cards. (not 5m332)

now responder bids 2M+1, artificial relay

method 1:
"bids under 3M are patterning out with 3 trumps; 3M, 3NT and 4M are natural non forcing and others show splinters."

method 2:
"3 cards bad hand 3 cards good hand 4 cards bad hand 4 cards good hand"

Of course you may introduce your favorite scheme also.

edit: added a line for post to make sense

[awm]

My preference is closer to the first method. Basically I play:

2NT/3M are non-forcing game tries
Suit bids below 3M are natural and forcing to game
Suit bids above 3M are splinters
3NT is choice of games, normally four trumps only
4M is to play

The suit bids below 3M can be 4-4 hand patterns, looking for the best game, or 5-4 hand patterns looking for slam (possibly in a side 4-4 fit).

I have two questions for the "ogust" crowd:

(1) How do you decide whether to play 4M in a 4-3 fit or 3NT? Don't you need to know why partner raised on three cards (i.e. where his shortness is) and not just that he did?

(2) Do you really want to play 3M on a 4-3 fit every time there's no game available? Certainly 2NT will be better a substantial percentage of the time, especially if responder has weak trumps.

[kenrexford]

This is not exactly the same, and I'm not sure what parallels it would offer, but here's my methods:

After 2NT (or, if you want, 2♠ after a heart raise), Opener shows whether he has four trumps or not by rebidding his minor if he has only three trumps. However, he will only have three trumps, as I play, with a cannot-reverse holding.

Thus,
1♣-1♥-2♥-2NT(♠)-3♣ shows 1345 pattern
1♣-1♠-2♠-2NT-3♣ shows 3145 or 3415 pattern
1♦-1♠-2♠-2NT-3♦ shows 3451 pattern
and 1♦-1♥-2♥ guarantees four-card support

After the either-or (club opening, spades raised), 3♦ by Responder can ask for clarification (3♥ = 3415, 3♠=3145).

If you definition actually is as limited as mine is, then this may work for you.

[grrigg]

If you insist that the opener is unbalanced isnt he constrained to have 5-4-3-1. 6-3-3-1 or 6-3-2-2 with 3 card support (suits listed in order of length not suit order)? The only 2 other reasonable shapes I see are 5-5-3-0 and 6-4-3-0 in which case partner is likely to bid the second suit instead of supporting. Since the shapes are so limited patterning out by bidding second suit (5-4-3-1) or rebidding original suit (6-3-3-1, 6-3-2-2) makes a lot of sense.