As noted by other's responding to your post, the Roman System of Distributional Bidding is a Canapé system. It's also a remarkably natural and easy to learn system. Unfortunately, ACBL/GCC regulations effectively prevent its use in most tournaments and events. A Canapé system within a "strict" natural (and ACBL/GCC legal) framework [where (1) responses to suit one bids are natural and (2) opening one bids and opener's NT rebids are natural] is easy enough. But how true to canapé would it be? If responses to opener's bid are natural, bidding theory still applies to opener's reverses: a better than minimum hand is required, since a preference to openers first suit forces the auction to the three level. If this is ignored, opener's rebid will have "huge" range of strengths. Opener must be careful in his selection of opening bid (preparedness) so that he will have a rebid that doesn't mis-describe his strength or distribution. For someone used to playing four card majors, this is quite a familiar process.

Unfortunately, Canapé's problems are much like SA's, suits must be sometimes be suppressed. It's just in canapé the suits causing the problems are different: xx AQxxx AJTx xx vs. Ax AKxxx AJTx xx. If you bid 1D-1S-2H on both hands, life will be difficult. One solution is to open 1H with the first hand. But then the diamond suit is in jeopardy to be lost. And we have the same conditions that gave rise to 5 card majors.

Competition by opponents can exacerbate the problems. Even Blue Club's canapé, which limits the strength of a 1D opener to 16 HCP, requires opener to have a "very good" 15-16 point hand for the 1D-1S-2H reverse. The first hand above would be opened 1H, the second 1D. Roman's Herbert responses and opener's artificial rebid of 1NT to show a minimum hand with five cards in the Herbert suit address the need to distinguish between the hands above (1D-1H!-1NT! with the first and 1D-1H!-2H with the second).

STANDARD AMERICAN HAS ONE PRIMARY ADVANTAGE OVER CANAPE: responder can preference (or false preference) to opener's long suit with a good hand that isn't quite good enough to issue a game invitation over opener's rebid. This gives opener another chance with a hand not quite good enough to reverse, raise a 1NT response, or jump shift. A secondary, valuable technique in SA, opener making a temporizing rebid in a second "suit", can be done in canapé also...opener just does it on the first round, opening in a three card minor. There is also the problem that a weak hand by responder that passes the opening bid may leave a two-suited opener in an inelegant contract.

Bottom line? Unless some compromises are made and "extreme" care taken in constructing a responding structure, I think the "canapé-ness", not to mention effectiveness, of such a system would be severely diminished. Still fun to play though!

Aloha,

Stu Akerman

PS: Here's what I want out of a natural canapé system: with the opening bid, responder must be able to assume: OPENER¹S SUIT IS EITHER SIX CARDS OR LONGER OR OPENER HAS AN UNBID SUIT FIVE CARDS OR LONGER. This makes it possible for responder to play negative doubles that show only "THREE" card support for unbid suits. What if opener has a balanced hand or a three-suiter? By playing 13-15 HCP 1NT openings and using 2D as a minimum 3-suiter, responder will only be "fooled" when opener is strong (16+ HCP), in which case the partnership has the values in reserve to recover. I've put a lot of work into polishing this, but it's tough working within the GCC and keeping it moderately simple.

SA