[Kungsgeten]

I got a bit inspired reading Perko's design goals of his Miles inspired unbalanced diamond system. Here's a little something based on canapé and strong(ish) club:

1♣ = 15+ balanced or 16+ unbal 4+ clubs or 18+ any
1♦ = 4+ suit, unbalanced 11-17. Includes major canapé, but not hands with 4 diamonds and 5 clubs. If 5♦ then 4+♣.
1♥ = Unbalanced 11-17. 4 hearts canapé or 6 hearts or 4-4-1-4. Never 5 hearts.
1♠ = Unbalanced 11-17. 4 spades canapé or 6 spades or 5-5 majors.
1NT = (11)12-14. Can be 4-4-1-4. Can have 5M332.
2♣ = Unbalanced 11-15, no major. 6+♣ or 5♣ and 4♦.
2♦ = Multi, weak major.
2♥♠ = 5 card suit and 4+ clubs. 11-15
2NT = Take a pick

Why the 11-17 range? To make the bids a bit more frequent. This may be a bad descision.

Why include 5M332 into 1NT? In order to show nature of hand as soon as possible, and be able to play forcing 1NT (or similar) and keep rebids pure.

Strong points:

- Pure opening bids, everything shows a suit except the strong club.
- Balanced hands are excluded from the one-level openings, thus 1NT forcing makes perfect sense (relays possible etc)
- Somewhat limited openings (could be even more limited if deciding to put 16-17 hands into 1♣)
- Should have few problems with rebids
- 2♣ should be more effective than versions that can include 5♣ and 4M.

Weak points:

- 1NT not very good for partscores (especially not when 5M332 is included)
- Would prefer not to open 1♣ with 15+ balanced.
- Unsure what response scheme would work best vs the strong club (perhaps Moscito or IMPrecision could work)
- Frequency for 1♦ and 1M is pretty low.
- 2M might not be the best opening bid

Possible tweaks:

- Polish/Swedish club instead of strong club
- Make 1♣ include all 16+ unbalanced
- Include some balanced hands in 1♦ (but that somewhat defeats the purpose)

Just a few examples of how continuations could be:

1♦---
1♥ = Relay, may be weak
...1♠ = (4)5+ spades
...1NT = (4)5+ hearts
...2♣ = 4+ clubs and 5+♦, 11-15
...2♦ = 6+ diamonds
...2M = NF reverse
...2NT = 6+ diamonds, (15)16--17
...3♣ = 5-5 minors, 15--17
1♠ = 5+ spades
1NT = 5+ hearts
2♣♦ = NF

1♥---
1♠ = Relay, may be weak
...1NT = (4)5+ diamonds
...2♣ = 5+ clubs
...2♦ = 5+ spades
...2♥ = 6+ hearts
...2♠ = NF reverse
...2NT = 6+ hearts, (15)16-17
1NT = 5+ spades
2m = NF
2♥ = NF

1♠---
1NT = Relay, may be weak
...2♣♦♥ = 5+ suit (2♥ can be 5-5 if min)
...2♠ = 6+ spades
...2NT = 6+ spades, (15)16-17
...3♣ = 5-5 majors, extras
...3♦ = 6+♦, extras
2♣ = NF
2♦♥ = 5+ hearts. Can be used to split ranges etc.
2♠ = NF

[perko90]

I'm glad something I posted was inspirational! : )

I have a few suggestions:

1) I would recommend your 1♣ = 17+ Bal, 16+ Unbal Here's why:
- canapé is very much a shape 1st bidding system and with your design in particular where a 5CM is not disclosed until the rebid, there's a huge incentive to show that shape. Therefore, it's probably best to keep the strength of the opening bids limited
- also, you already have to include hands like 16 HCP and 5M & 4 C's in 1♣. For sequences like 1♣-1♦; 1M it's still not clear whether opener has only 16 or the 18+ variety and so the advantage of 1♣ being 18+ except for limited case A or B is somewhat lost
- see #2 below for the balanced hand recommendation

2) Go ahead and include balanced hands in 1♦. One of the big advantages of my Unbal 1♦ is that it has many of the advantages of canapé within a 5CM structure, but when you're already playing a canapé system, there's not as much to gain. You've taken some care to ensure you don't make a bad canapé rebid, but I think if you keep your 1 level bids limited and your relays, when holding a weak hand, to have at least 2 cards in the relay suit, the danger largely evaporates. Responder can bid 2m NF if they don't have 2-card tolerance for the relay suit. Now, you still have to solve the issue of the 5332 hands w/ a major that's outside the 1NT range, but that hand type is always trick in a canapé context.

3) Highly recommend including 4-4 major hands in with your 1♥ opening. A 1NT rebid can show this hand type. With 1♦ including 5-card majors, you don't want to include the 4441 hand types in it. And getting the 4-4-1-4 hand shape out of 1NT is nice, too. Once again, if the 1♥ opening is limited to 11-15 and the 1♠ relay promises 2-card tolerance or a rebid then a 2♠ canapé rebid isn't too scary/misleading. And thus, you can free up the 1NT rebid.

If you adopt #3 above and open (41)44 hands 1M (as most canapé systems I've seen do), your 1♦ opening could even deny a 4CM.

[Free]

I never played pure canapé but I always liked the idea of opening either a 6 card singlesuiter or a canapé hand naturally. But I don't like the fact that you still need to show the difference between min and max hands immediately. This also allows 1♦-1♥-1NT/2♣ to solve the minor twosuiters.

What I would definitely consider is to swap the 2♦ and 2M openings. That makes it no longer BSC (because 2♦ now shows opening values), gives opener a chance to show strong offensive hands after partner's response (a nice 5-5 or 6-5 for example), and allows you to preempt 2M more agressively.