[Zelandakh]

Since we discussed this structure recently I will mention that it also can be adapted somewhat for Swedish Club:

1♣ - 1♦
======
1♥ = 17-19 any or 22+ bal
1♠ = 11-13 bal with 4-5 spades
1NT = 11-13 bal with 2-3 spades
2♣ = unbal GF or 17+ 3-suited
2♦ = strong 2 in a minor
2♥♠ = strong 2
2NT = 20-21 bal
3♣ = 24-25 bal with 4-5 hearts
3♦ = 24-25 bal with 4-5 spades
3♥ = 24-25 bal with no 4 card major

Obviously you lose the drop dead in hearts but that is rare with the strong hands included; meanwhile you make the drop dead in spades much more viable.

[straube]

Zelandakh's continuations look pretty good to me. Are the 17-19 5M4M opened in a major or 1C? Those are potential problem hands. Also I'm not sure what exactly is included in 1C-1D, 2C here or how the bidding would continue. Probably good decision here to give up on canape 17-19 4M/5m.

I'd thought that 1C-1D, 1N would invite speculative doubles in balancing seat but if responder can have 7-11 or so then not.

[Kungsgeten]

Yes your structure is the inspiration for my previous post Zel. The main difference is that I included 17--19 unbal with 4+ spades in the 1S rebid along with the weak hand. This is not necessary, but it caters to Straube's comment on 17--19 with 5-4 majors being a problem (as the 17--19 range of the 1H catch-all denies 4+ spades unless 5-5 spades and a minor). I also did not include 17+ three-suiters anywhere; these would have to be treated as balanced I guess (4441 that is).

In order to clarify Straube: The 1C opener has either 11--13 bal (includes 4-4-1-4 and 5m332, but not 5M332) or any 17+ hand (but the 2NT opening may be used for a strong balanced range, we could use our 2D multi for some strong hands too but prefer not to). When responder bids 1D he has either 0--7 hcp (but not 0--4 with a 6 card major, these respond 2D, also responding 3X is a natural "preempt") or 8--11 4333/4432 without a 4 card major. In third/fourth seat we've been thinking of playing 1C as 10--14 bal and the strong balanced range starting at 18, making our 1NT opener 15--17 instead of 14--16.

[Kungsgeten]

Another idea, based on yunling's previous post (but he made 1D pos
and 1S+ semi-pos):

1C---
1D = Any 6--12
...1H = 17+ relay. Would later relay break with min I guess.
...1S = Natural weak
...1N = Weak, 2--3 spades
...Higher = Natural strong
1H = 0--5 (weak opener has too pass)
1S+ = 13+. Strong opener relays, weak opener may relay or support

This is nice for relay purposes, but finding 4-4 hearts after
1C--1D is hard and I think 1H as 0--5 will lead to some bad
boards. Also fourth hand interference after 1C--1D would be a
pain.

[relknes]

yunling, on 2014-May-06, 12:20, said:

Has anyone tried…
1♣-1♦-
1♥=weak NT
1♠=21+
else=17-20

I have played with some similar ideas, in a context where 1♣-1♦ was either 0-7 or a hand that could force to game opposite 11-13 balanced.
After 1♣-1♦:

1♥ = 11-13 balanced
-------P/1♠/2m = to play
-------1N = pick a minor
-------2M = 4 or 5 card suit, GF
-------2N = long minor suit, debating between 3N and 5m
-------3x = sets trump absolutely, GF
-------etc...
1♠ = a hand that would open 2♣ in a standard system but doesn't qualify for a 3x jump or a NT bid
-------1N = waiting. Any hand that doesn't qualify for a 2x bid
-------2x = at least KQxxx or Kxxxxx
1N = 17-19 balanced
2x = 17-21(22), natural. Partner may pass with 0-2(3) points
2N = 22-23 balanced
3x = single suited, game in hand, sets trump absolutely

20-21 balanced would have opened 2N.