[DavidKok]

Based on the comment below:

helene_t, on 2023-April-15, 04:57, said:

This sounds similar to Scanian?
I played a congress event with Cascade in New Zealand, we played this NT ladder:
11-12: open 1M if you have one, otherwise pass (maybe 1♦ in 3rd seat if you have 4 good diamonds)
13-15: 1NT
16-22: 1c
I worked quite well but I wondered if the frequency of 1M of a 4card suit was too low to bother.

In modern Precision the opening structure is (similar to):

• 1♣: 16+ unbal or 17+ bal
  
• 1♦: 11-15, 2(+) diamonds
  
• 1♥: 11-15, 5(+) hearts
  
• 1♠: 11-15, 5(+) spades
  
• 1NT: 14-16 (semi)bal, typically contains more semibalanced hands than traditional 1NT openings
  
• 2♣: 11-15 6(+)♣, no 5cM
  
• 2♦: 11-15 '4=4=1=5 minus a card'

This opening structure gets the benefits of the powerhouse 1M openings and sound 1NT opening, but introduces friction in the other openings. 2♣ is descriptive and very sound (compared to the old Precision 2♣ which showed 5(+) and may have a 4cM), but is low frequency. 2♦ is extremely rare and arguably a waste of an opening bid. 1♦ is highest frequency by far (~15.3% of all hands, compared to 5.7% for 1H, 5.9% for 1S and 1.6% for 2C) and contains hands such as 1=4=3=5 or 4=2=2=5 as well as 11-13 balanced, long diamonds, or both minors (possibly longer clubs, e.g. 2=2=4=5 or 4=0=4=5). There's also a modern style where 1♦ is 0+, incorporating also the hands from the 2♦ opening. As a funny aside, this 1♦ opening bid is natural^tm even if it can be opened on a void.

Personally I think strong club systems are very interesting, and Precision(-esque) systems have an edge over standard systems. One of the issues with the standard modern Precision system can be identified very easily. If we set 1M as a 5cM, 2♣ as 6(+) and 1♣ as 16+ any shape, the 11-15 4=4=0=5 hands (and those similar to it) have no good bid. The main solution is a nebulous diamond of some sort. This bumps the frequency of 1♦ sky high - including diamonds hands, weak balanced hands and unbalanced hands (possibly short diamonds) that have no good place in the system - while making it vulnerable to interference.

One older alternative is to play 4cM instead, which prompted this post. Compared to the scheme above the problem hand is much more gentle now: 3=3=2=5 (no 4cM and no 6c♣) is balanced and doesn't have a lot of playing strength, so it is much less difficult to fold into the opening structure than the 4=4=0=5-like or (41)=3=5 or so hands. In addition opening 1M with a weak (11-13) notrump with a 4cM greatly reduces pressure on 1♦ and has a mildly preemptive effect, while responder won't easily get too high facing a limited opening. In fact, if we are a bit naive for a second, we can glue together:

• 1♣: 16+ unbal or 17+ bal
  
• 1♦: 11-15, 4(+) diamonds
  
• 1♥: 11-15, 4(+) hearts
  
• 1♠: 11-15, 4(+) spades
  
• 1NT: 14-16 (semi)bal, typically contains more semibalanced hands than traditional 1NT openings
  
• 2♣: 11-15 6(+)♣, no 5cM

There are some issues with this scheme. The 11-13 balanced hands without a 4-card suit outside clubs, i.e. exactly 3=3=3=4, 3=3=2=5, 3=2=3=5 and 2=3=3=5, have no opening bid. Hands of x=y=4=5 type have to open 1♦ and (presumably) rebid 2♣, so the ambiguous minor length issue from standard Precision persists. You also need firm rules about when (not) to open a 4cM - do you play canapé either never, or only with major-minor hands, or always, or always when there's no club suit involved, or something else?
I've recently become very interested in these systems. Canapé style strong club 4cM systems solve a lot of the problems that natural system have, and incur only minor costs in return. The idea of simply passing the 11-13 (or 11-12, if you shift 1NT down to 13-15) balanced hands without a 4cM is wild but not outlandish, alternatively dropping 1♦ down to 3(+) seems perfectly playable as well (and you have to DSI with 3=3=2=5). Also the response structure can be simple and effective. In playing around with this I also looked at the opening frequencies (of one particular flavour of system of this type, so this would probably change quite a bit depending on exact system choices), and was pleasantly surprised:

Spoiler

• 1♣: 16+ unbal or 17+ bal, ~7.9%
  
• 1♦: 11-15, 3(+) diamonds (4(+) 91% of the time) canapé, ~6.7%
  
• 1♥: 11-15, 4(+) hearts canapé, ~10.2%
  
• 1♠: 11-15, 4(+) spades canapé, ~8.6%
  
• 1NT: 14-16 (semi)bal, contains more semibalanced hands than traditional 1NT openings, ~8.2%
  
• 2♣: 11-15 5(+)♣, no 4cM, ~2.5%

2♣ and 1♦ are somewhat underloaded, but 2♦ and up are freed and there are no serious rebid or continuation issues.

Over the past weeks I've assembled a pretty decent literature list of strong club 4cM systems. If people have experience with systems like this, in particular if you are familiar with interesting bidding tricks that go together with systems like this, I'd love to hear all about them.

[pescetom]

DavidKok, on 2023-April-15, 07:08, said:

In fact, if we are a bit naive for a second, we can glue together:

• 1♣: 16+ unbal or 17+ bal
  
• 1♦: 11-15, 4(+) diamonds
  
• 1♥: 11-15, 4(+) hearts
  
• 1♠: 11-15, 4(+) spades
  
• 1NT: 14-16 (semi)bal, typically contains more semibalanced hands than traditional 1NT openings
  
• 2♣: 11-15 6(+)♣, no 5cM

There are some issues with this scheme. The 11-13 balanced hands without a 4-card suit outside clubs, i.e. exactly 3=3=3=4, 3=3=2=5, 3=2=3=5 and 2=3=3=5, have no opening bid. Hands of x=y=4=5 type have to open 1♦ and (presumably) rebid 2♣, so the ambiguous minor length issue from standard Precision persists. You also need firm rules about when (not) to open a 4cM - do you play canapé either never, or only with major-minor hands, or always, or always when there's no club suit involved, or something else?
I've recently become very interested in these systems. Canapé style strong club 4cM systems solve a lot of the problems that natural system have, and incur only minor costs in return. The idea of simply passing the 11-13 (or 11-12, if you shift 1NT down to 13-15) balanced hands without a 4cM is wild but not outlandish, alternatively dropping 1♦ down to 3(+) seems perfectly playable as well (and you have to DSI with 3=3=2=5).

This is actually quite similar to a simple strong club system played around here, only that they play 1NT 12-15 and will pass 11 balanced. They play canape' with major-minor hands, I've never dug deeper for detailed rules about canape' or 1NT shapes. It works well enough and is easier to learn than natural systems.

[johnu]

DavidKok, on 2023-April-15, 07:08, said:

Over the past weeks I've assembled a pretty decent literature list of strong club 4cM systems. If people have experience with systems like this, in particular if you are familiar with interesting bidding tricks that go together with systems like this, I'd love to hear all about them.

I play a modified version of Blue Team Club (BTC), 4 card majors, canape, catch-all 1♦ showing 2+ diamonds, standard 15-17 strong NT. The upper range of non 1♣ openings is 1 point more than Precision. There are a number of books (all out of print????) on BTC by various authors.

The major changes to original BTC are centered on removing ambiguity from possible canape sequences, and removing opening 1M with flat hands.

[DavidKok]

johnu, on 2023-April-16, 04:14, said:

The major changes to original BTC are centered on removing ambiguity from possible canape sequences, and removing opening 1M with flat hands.

What's the downside to opening 1M with a flat hand? Which sequences are troublesome? If we move those hands to 1♦ do you not end up with standard precision except 4M5(+)m hands open 1M too?

[steve2005]

Bidding after 1M when it promises a 5-card major is so easy. Anyone Intermediate or above can easily learn system.

If there a good system write-up using 4-card majors involving canape?

[pescetom]

steve2005, on 2023-April-16, 10:19, said:

Bidding after 1M when it promises a 5-card major is so easy. Anyone Intermediate or above can easily learn system.

Hmmm.
Just last night I encountered a pair of intermediates (BBO accounts dated 2005) who bid the uncontested auction:
1♠-1NT
2♣-2♠
pass
As my companion had passed in first seat and I held 4 HCP, I deduced that they struggled with bidding after 1M 5-card
(and probably only that, as they placed in the top half of the field).

steve2005, on 2023-April-16, 10:19, said:

If there a good system write-up using 4-card majors involving canape?

Here is a write-up of a primitive such system (unfortunately in Italian and on http):
Fiori Torino
If you count the pages you can see why those who play it are reluctant to pass to natural systems

[nullve]

johnu, on 2023-April-16, 04:14, said:

The major changes to original BTC are centered on removing ambiguity from possible canape sequences, and removing opening 1M with flat hands.

(5332) is balanced but not flat? (In pilun's Symmetric Relay book, flat hands have either (4333) or (4432) shape.)

[pescetom]

nullve, on 2023-April-16, 12:15, said:

(5332) is balanced but not flat? (In pilun's Symmetric Relay book, flat hands have either (4333) or (4432) shape.)

Now that 5332 is considered balanced rather than semi-balanced, it would be useful to have some term to distinguish the original balanced hands (4333 or 4432).
I refer to them as "truly balanced", but maybe "flat" is better (although to me it suggests a semi-balanced hand that wants to play in NT).

[johnu]

nullve, on 2023-April-16, 12:15, said:

(5332) is balanced but not flat? (In pilun's Symmetric Relay book, flat hands have either (4333) or (4432) shape.)

I meant 4-3-3-3 or 4-4-3-2 (not in 3rd seat), as well as 5-3-3-2 where the 5 card suit is a minor. Not opening 1M with a 5 card suit is another system entirely.

[johnu]

steve2005, on 2023-April-16, 10:19, said:

If there a good system write-up using 4-card majors involving canape?

The best one I've seen is https://www.amazon.c...k/dp/B0006CU29G which has a lot of bidding examples. Other BTC books don't have as much detail.

[johnu]

DavidKok, on 2023-April-16, 09:12, said:

What's the downside to opening 1M with a flat hand? Which sequences are troublesome? If we move those hands to 1♦ do you not end up with standard precision except 4M5(+)m hands open 1M too?

Unresolved canape sequences are inherently troublesome. e.g.

In classic BTC, this sequence

---

shows either 4+♠ and 5+♥, or 5+♠ and 4+♥. Simplifying, just consider either 4-5 or 5-4 in the majors and responder has a minimum with 2-2 in the majors. How do you get to your 5-2 fit instead of your 4-2 fit? Suppose responder is 3-2 in the majors and has an invitational hand if there is a 5-3 fit, but not for a 4-3 fit? Similar problems for other canape suit combinations.



Removing flat hands from 1M openings is little for hand evaluation. 4-3-3-3 hands are recognized by most as not being strong playing hands for a given point count. To a lesser extent, also 4-4-3-2 hands. You also may have to rebid 2NT after a 2/1 with the wrong honor distribution, or raise responder with 4 card minor support when responder can't tell if you are balanced or unbalanced. In redesigning BTC, opening 1♦ looked better, but YMMV.

Classic BTC also has the concept of canape reverses. e.g.

---

This type of sequence shows 4+♦, 5+♠, a maximum non 1♣ hand with a very good spade suit and concentrated strength in spades and diamonds. That's unlike any sort of standard or Precision bidding.

[DavidKok]

Thank you, so also the ascending canapé sequences.

The systems I've been looking at resolve most of the shape ambiguity, though some (seem to choose to) include it regardless, mostly with clubs. I'm still learning about these systems but I don't think these are significant issues.

The Blue Club system splits the 11-16 range (1♣ starting at 17+) into three, and has different opening requirements for each range, with additional demands on suit quality. If, again, I take a naive approach and do away with this strength split I do not immediately see issues with the system. For example, over 1♦ (optimised for simplicity, not effectiveness):

• Pass: risky in canapé systems. This should promise some diamond length and absolutely no game chances, as well as some values. With a very weak hand it is usually better to ask for opener's possible second suit. ~0-9 with (2)3+ diamonds.
  
• 1♥: 5(+) hearts, forcing. Opener 'never' has 4 hearts (only with 7(+) diamonds do we conceal the 4-card heart suit).
  
• 1♠: 5(+) spades, forcing. Ditto.
  
• 1NT: 0-11 SF (though perhaps it is better to insist on a minimum strength requirement), may have one or both 4cM. Requests that opener passes with 11-13 (semi)balanced, or rebids naturally otherwise.
  
• 2♣: GF relay, asks for shape information. See below for rebids. Denies 5(+)M and denies good diamond support, so this is natural or balanced (the worst shape included is 4=4=3=2).
  
• 2♦: Inverted minor, 4(+).
  
• 2♥: Whatever you please.
  
• 2♠: Ditto.
  
• 2NT: Ditto.
  
• 3♣: Ditto, though I think having an intermediate jump shift (~9-11, 6(+) clubs, no 5cM) is probably good. Taking this hand type out of 1NT can be beneficial.
  
• 3♦: Inverted minor (weak), (4)5(+) diamonds. Don't go crazy with 4♦ and shortness in one major - that's probably partner's long suit, and you can get to 3♦ through 1NT.

Over 1♦-1NT:

• Pass: 11-13 balanced. It is also permissible to pass with a semibalanced hand and no great desire to bid on, e.g. with an x=y=5=4 with values in the majors, a 6♦322 minimum or perhaps even with a minimum 4♦5M with a lousy major suit without game prospects.
  
• 2♣: 5(+)♦4(+)♣. Traditionally ambiguous, but I don't have an issue opening 2♣ with an unbalanced 4♦5♣ hand. Since 2♣ denies a 4cM (canapé) we can include that hand type there without great risk.
  
• 2♦: 6(+)♦.
  
• 2♥: 4(+)♦5-6♥, hearts at least as long as diamonds (so 5-5 is permissible). With a good 6c♥ and so-so 4c♦ we can also open and rebid hearts.
  
• 2♠: 4(+)♦5-6♠, ditto.
  
• 2NT: DNE (I think traditionally this shows a top-of-the-range 6c♦ hand).
  
• 3♣: 5(+)♦5(+)♣, maximum/good concentration of values.
  
• 3♦+: Whatever you like, probably 'same as the bid one level lower, but an extra card and top of the range/good concentration of values'.

Over 1♦-2♣:

• 2♦: Balanced, may include a semibalanced minimum (as above). Staying low on this hand type and not hogging NT is probably important.
  
• 2♥: Same as over 1NT.
  
• 2♠: Same as over 1NT.
  
• 2NT: DNE, though it's easy enough to put something artificial here (e.g. transfers from 2NT up, or a top-of-the-range 3m rebid while the direct bids show a minimum).
  
• 3♣: 5(+)♦4(+)♣.
  
• 3♦: 6(+) diamonds (but see 2NT).
  
• 3♥+: Whatever you like.

I'm sure there's more effective schemes (i.e. transfers?) but this seems to handle most of my problems.

There's still some unresolved canapé sequences. The 5M4(+)♣ hands are annoying as you can't bid them canapé, so you either have to play some form of constructive (Roman?) two bids, i.e. 2♥/♠ showing 11-15 5♥/♠4(+)♣, or accept that 1M-1X; 2♣ is ambiguous. I think 1M-1X; 2m should be artificial anyway, it is seldom right to stop in 2m exactly, so if it's just the clubs I think some ambiguity can be overcome. I also don't know what to do with 65 major-minor hands, especially 6m5M (with 6M5m you can bid as a 6M4m ascending canapé). But these are rare and frequently attract interference, plus I'm trying to keep things simple.


I learned a lot about these systems from Arturo Franco and Marco Pancotti's writeup of the Blue Team Club, translated by and available on Daniel Neill's website. They use 2♣ and 2♦ over 1M as two artificial asking bids, I simply swapped those out for a 'modern' 2/1 GF style asking bid. The same response structure also works over 1M-2♣ (i.e. 2♦ BAL or minimum semibal/three-suited, 2M 6(+), 2oM canapé, 3m canapé, 2NT artificial 5M4(+)♣).

[Kungsgeten]

If you don't want "unresolved canapé sequences", and no nebulous diamond bid, I think you need some kind of constructive two-suiters at the two-level (like Roman 2M). I've toyed with the following idea, and find it a bit strange that I haven't seen anyone play like this (might be major flaws that I don't see):

1C = Strong
1D = 4+D. 4441, or 4D 5+M, or 5D 4+C, or 6+D.
1M = 4M and longer side suit, or 6+M. Could include balanced shapes too I guess.
1NT = Weak.
2C = 6+C or 5C and 4D.
2D = Multi.
2M = 5+M and 4+C.

My intention was to use this with a Swedish Club, so 1C would be 11-13 NT or 17+ any, while 1NT would be 14-16 NT.

There's also the Moscito/Magic Diamond style MAFIA systems where the major openings are a bit nebulous: could be any two-suiter (canapé or not) as well as single-suited (5332 counts as single-suited here). I've also seen variants including 4432 and 4333 shapes. Magic Diamond uses transfer responses to the major suit openings, so no negative 1NT. Here's my old system notes with a strong club and transfer style Magic Diamond openings (very similar to MOSCITO): http://snortingmarad...k/relayclub.pdf

A friend of mine uses a nebulous diamond that denies holding a four card major:

1C = 15+ any
1D = 10-14, unbalanced and no major. 0+ diamonds (could be 3-3-0-7 for instance).
1M = "Magic Diamond": 10-14, 4+M but not 4333/4432. Longer minor possible.
1NT = 11-14, no five card major.
2X = Weak.

Here's a "Lite Version" of Magic Diamond: http://www.brenning....MagicDlight.pdf

[nullve]

Kungsgeten, on 2023-April-17, 07:34, said:

If you don't want "unresolved canapé sequences", and no nebulous diamond bid, I think you need some kind of constructive two-suiters at the two-level (like Roman 2M).

1st/2nd:

P = "normal" OR 11-13, either 3343 or 3352*
1♣ = "16+" unBAL OR 17+ BAL
1♦ = "10-15", either 1-suited w/ 6+ C, 4+C5+M (C never longer) or C+D 2-suiter*
1♥ = "10-15", either 1-suited w/ 6+ H, 4+H5+O (H never longer) or 4H(441) OR 11-13 BAL, 4-5 H
1♠ = "10-15", either 1-suited w/ 6+ S, 4+S5+O (S never longer) or 4144 OR 11-13 BAL, 4-5S2-3H
1N = 14-16 BAL*
2♣ = "10-15", either 1-suited w/ 6+ D or 4+D5+M (D never longer)
(...)

P-?:

P = 0-7, usually BAL
1♣: as in 1st/2nd OR 8-10, BALish**
1♦: as in 1st/2nd OR 11-13, either 3343 or 3352**
(...)

1♦-1M; ?:

1N = 2-suited w/ 5+D4+C (C never longer) C+D 2-suiter OR ___?
2♣ = 2-suited w/ 4+D5+C (D never longer) C 1-suiter
(...)

2♣-?:

P: rare!
2♦ = to play opposite the 1-suited hand
2♥ = INV w/ 5+ H OR any GF
...2♠ = 5+ S
......2N = GAR relay (GF)
......3♣/♦/♥ = NAT NF
......(...)
...2N = 1-suited
......3♣ = GF relay
......3♦/♥ = NF
......(...)
...3♣+ = 5+ H, GAR developments (GF)
2♠ = INV, 5+ S
...P = MIN, 5-H2(3)S
...2N = MIN, 5H1-S
...3♣ = D 1-suiter (and likely 1- S if MIN?)
...3♦ = MAX, 5+ H
......3♥ = 2 H
.........3♠ = 5H2S
.........3N = 5H1-S
.........4♣+ = 6+ H
......3♠ = 6+S1-H
.........3N = 5-6H1-S
.........(...)
...3♥ = MIN, 6+H2-S
...3♠ = INV, 3 S
...(...)
...4♠ = to play
(...)


* Alternatively:

P = "normal"
1♣ = as above OR 11-13, either 3343 or 3352

or

P = "normal"
1♦ = as above OR 11-13, 3343
1N = as above OR 11(12?)-13, 3352

** Alternatively,

1♦ = as in 1st/2nd OR 11-13, 3343
1N = as in 1st/2nd OR 11-13, 3352

This post has been edited by nullve: 2023-April-19, 03:40

[Kungsgeten]

nullve, on 2023-April-19, 02:18, said:

1♦ = "10-15", either 1-suited w/ 6+ C, 4+C5+M (C never longer) or C+D 2-suiter*
1N = 14-16 BAL*
2♣ = "10-15", either 1-suited w/ 6+ D or 4+D5+M (D never longer)


1♦-1M; ?:

1N = 2-suited w/ 5+D4+C (C never longer) OR ___?
2♣ = 2-suited w/ 4+D5+C (D never longer)

Nice idea! Though I think that 1D-1X; 2C should show 6+C, so the 1NT rebid should probably be minors 5/4 either way.

[nullve]

Kungsgeten, on 2023-April-19, 03:35, said:

Nice idea! Though I think that 1D-1X; 2C should show 6+C, so the 1NT rebid should probably be minors 5/4 either way.

Aargh, yes. Will edit my post.

[DavidKok]

Kungsgeten, on 2023-April-17, 07:34, said:

If you don't want "unresolved canapé sequences", and no nebulous diamond bid, I think you need some kind of constructive two-suiters at the two-level (like Roman 2M). I've toyed with the following idea, and find it a bit strange that I haven't seen anyone play like this (might be major flaws that I don't see):

1C = Strong
1D = 4+D. 4441, or 4D 5+M, or 5D 4+C, or 6+D.
1M = 4M and longer side suit, or 6+M. Could include balanced shapes too I guess.
1NT = Weak.
2C = 6+C or 5C and 4D.
2D = Multi.
2M = 5+M and 4+C.

This is almost identical to what I'm trying. I also can't spot any major flaws. My main differences are that I'm trying strong NT, so 1♦ through 1♠ include 11-13 BAL (most older systems I've run into that play a similar style use a 'weak' 12-15 BAL and hope to survive, but this decision has consequences throughout the system). I also loathe the 2M openings, and I'm wondering if opening 1M on them is not the lesser of evils, even if we might lose the 5-3 fit in competition.
I don't see another major flaw with opening 1♦/1♥/1♠(/2♣) with 11-13 BAL. We'd (almost always) open our longest suit with this hand type, and 1NT ~0-11(12) SF is completely safe since we excluded 14-16 BAL, so the upper range of the opening always has a rebid. Having 1♦ (practically) deny a 4cM can also simplify the response scheme.

Kungsgeten, on 2023-April-17, 07:34, said:

My intention was to use this with a Swedish Club, so 1C would be 11-13 NT or 17+ any, while 1NT would be 14-16 NT.

There's also the Moscito/Magic Diamond style MAFIA systems where the major openings are a bit nebulous: could be any two-suiter (canapé or not) as well as single-suited (5332 counts as single-suited here). I've also seen variants including 4432 and 4333 shapes. Magic Diamond uses transfer responses to the major suit openings, so no negative 1NT. Here's my old system notes with a strong club and transfer style Magic Diamond openings (very similar to MOSCITO): http://snortingmarad...k/relayclub.pdf

A friend of mine uses a nebulous diamond that denies holding a four card major:

1C = 15+ any
1D = 10-14, unbalanced and no major. 0+ diamonds (could be 3-3-0-7 for instance).
1M = "Magic Diamond": 10-14, 4+M but not 4333/4432. Longer minor possible.
1NT = 11-14, no five card major.
2X = Weak.

Here's a "Lite Version" of Magic Diamond: http://www.brenning....MagicDlight.pdf

Thank you, this is very interesting!

[DavidKok]

nullve, on 2023-April-19, 02:18, said:

1st/2nd:

P = "normal" OR 11-13, either 3343 or 3352*
1♣ = "16+" unBAL OR 17+ BAL
1♦ = "10-15", either 1-suited w/ 6+ C, 4+C5+M (C never longer) or C+D 2-suiter*
1♥ = "10-15", either 1-suited w/ 6+ H, 4+H5+O (H never longer) or 4H(441) OR 11-13 BAL, 4-5 H
1♠ = "10-15", either 1-suited w/ 6+ S, 4+S5+O (S never longer) or 4144 OR 11-13 BAL, 4-5S2-3H
1N = 14-16 BAL*
2♣ = "10-15", either 1-suited w/ 6+ D or 4+D5+M (D never longer)
(...)

[...]

This looks amazing! The 1M openings are identical to what I'm looking for, but swapping the diamonds and clubs is very interesting! I don't feel a pressing need to open most 10-counts myself, but that's easy to adjust in either direction without changing the system. I'm not sure about passing some of the 11-13 BAL diamonds hands though. The Italians struggled with this hand type with clubs (apropos your minor suit swap) and played 1NT something like "15-17 any or 13-14 with primary clubs, pass 12 HCP BAL with primary clubs" and it's not unheard of to pass out some minimum NT hands without a major suit, but ideally they'd be included somehow. Personally I lean towards your "P = as normal, 1♦ = as above or 3=3=4=3 11-13" option, and the 5♦332 11-13 hands will need some finagling (one option is to, depending on the exact hand, upgrade them into a 14-count, pass them out, or open 2♣ with concentrated values).

Swapping the minors near guarantees that opener gets a rebid over 2♣, allowing for canapé hand types in that opening. This comes with a slight downside of reduced pressure on the opponents (who also get two rounds of bidding), but the upsides seem significant. I think this is brilliant, and would love to explore this in more detail. I think optionally putting 5♦332 11-13 and even 5♦4♣ 'not semibalanced' in 2♣ won't cost too much, making the 1♦ opening even less nebulous.

[Kungsgeten]

Putting balanced hands into nullve's 1D opening seems a bit problematic, since 1D-1M; 1NT will probably be needed for balanced hands. In that case I think that the 1H response should be some kind of waiting bid:

1D--
1H = 5+H or waiting.
1S = 5+S.
Higher = Not sure. One alternative is that 1H is "waiting" and the 1NT response shows 5+H.

1D-1H;
1S = Minors.
1NT = Balanced.
2C = Single-suited.
2D = 5S and 3H??
2M = Canapé.

Possible solutions if you want to play strong NT:

- Play Swedish Club: use 1C as 11-13 NT or 17+ any)
- Play Swedish Club but denies a major if weak NT: 1C is 11-13 NT no major, or 17+. 1M can be balanced (and 4+ suit) if 11-13.
- Play nullve's suggestion that 1D could be opened on 3-3-4-3 (so could be 3 clubs). Use the 2D opening as "Bailey two bid" showing 11-13 hcp 5-6 diamonds and 2-3 cards in each major.

[DavidKok]

Ah, I see. Without the minor suits swapped I had

1♦-1♠ (as an example):

• 1NT: 11-13 BAL 2 spades, so 2=3=4=4 or 2=3=5=3.
  
• 2♣: 11-15 5(+)♦, 4(+)♣ but almost always exactly 5=4 (by failure to jump rebid), at most 2 spades.
  
• 2♦: 11-15 6(+)♦, at most 2 spades.
  
• 2♥: 4(+)♦5(+)♥ canapé, at most 2 spades(?).
  
• 2♠: 3 spades, minimum.

and higher bids not too complicated (spade raises, more extreme natural hands, BW Death hand etc. all slot in nicely). By swapping the minors we need the 2♣ rebid for 6(+) as well as the 4♦5♣ unbal hand, which could be solved with transfers but that consumes the 1NT rebid. Am I understanding the problem correctly?

One design principle that I've been leaning towards is that we 'never' want to play exactly 2♣. Pretty much all modern systems I know replace 2♣ on all auctions with some artificial call enabling more accurate descriptions throughout the system, and in the latest Vanderbilt 2♣ was the final contract on 0 out of 360 deals. With that in mind it might be possible to resolve this issue by playing 2♣ artificial and (mostly) forcing, expecting to get another round to untangle the 4♦5♣ hands from the 6(+)♣ hands. This would be somewhat protected by the system since the bid shows clubs, is limited by the opening and further limited by failure to rebid 3♣ (or the likes), so in fact this 'artificial' bid would not need to be forcing at all. And (not a great argument, I know) standard bidders do it too on 1♣-1♠; ?.