[JLilly]

In both weak-NT and strong-NT contexts, it seems like the opener of 1m chooses the particular suit based on a "better minor" (or "least bad minor") criterion, when a lot of the time that's not as meaningful a distinction as the hand's shape, and in the case of a balanced hand, whether the 1m opener has a 4cM to raise responder with and what they intend to do after the frequent 1m-1X; 1NT-2om or 1m-1X; 1NT-2m auction (whatever its meaning, as a raise, as checkback, as NMF, etc.).

The most useful information you can tell responder about both ♠Qx ♥x ♦KQJxx ♣AJxxx and ♠KJxx ♥AQxx ♦xxx ♣Kx surely is something other than the fact that your clubs are not longer than your diamonds.

What methods do people play for getting more meaning out of the 1m openings? I've heard "unbalanaced diamonds and balanced clubs" -- do people conceive of methods in terms of "pre-answering" a checkback Stayman from partner after the 1NT rebid on balanced hands? An emphasis on showing or denying 4-card majors? A sort of L-shaped scheme where 1♣ is distributional with clubs OR balanced, and 1♦ is everything else? And for these purposes, is being "balanced" about lacking length? Lacking shortness? Being focused on finding a major fit?

Thanks!

[steve2005]

There are many different methods. If you really want a better method for minors you would use 4-card majors.

[helene_t]

There are a few people on this forum who like "coded minors" which is a treatment in which
1♣=(12-14 balanced) OR (unbalanced with primarily clubs)
1♦=(18-19 balanced) OR (unbalanced with primarily diamonds)

The advantages are:
- responder can raise 1♦ aggressively (sometimes with 3-card support), knowing that if opener does not have 5+ diamonds he almost certainly has enough to bid 3NT.
- opener is not under obligation to bid again with 18-19 in auctions like 1♦-(1♠)-pass-(2♠)-? because responder is very likely to be broke (given that he couldn't freebid opposite an opener who has denied a balanced minimum). This avoids some unhealthy 2NT contracts and such.
- responder can pass the 1♣ opening even with 1-2 clubs knowing that if clubs is not a playable strain, opps likely have game so 1♣-3 is an OK result
- the 2NT rebid is not necessary to describe a balanced hand so it can be used for other purposes
- you don't give opps information about your minor suit length

The disadvantage are
- responder can't make a nonforcing raise of clubs with 4-card support
- responder can't pass the 1♦ opening without some diamond length
- more difficult to find the right minor suit lead

Some prefer to play the opposite, i.e. 1♣ contains the strong balanced. And of course you can also play it in a weak or baby nt context.

[JLilly]

steve2005, on 2017-August-08, 17:37, said:

There are many different methods. If you really want a better method for minors you would use 4-card majors.

Consider it a constraint of the problem that you're using 5-card majors. What I really want is a method, within a 5-card major natural system, to give more useful information with the choice of which minor is opened.

[JLilly]

helene_t, on 2017-August-08, 17:44, said:

There are a few people on this forum who like "coded minors" which is a treatment in which

Thanks, Helene! I tried some searches on the forums for this kind of thing but came up short -- do you have any search terms that could help, or know of any threads in which this is discussed? Tx, JL

[helene_t]

hi JL,

This thread for example: http://www.bridgebas...-suit-openings/

It has come up in other threads also but there may not be other threads dedicated to the topic.

[dokoko]

The following method is becoming popular among experts in the last years:

1♣ 2+ clubs, contains all balanced hands outside the 1nt range (including 5♦332 and - if you wish - 5M332),
responses hereto are T-Walsh (1♦ shows 4+ hearts, 1♥ shows 4+ spades).
1♦ 4+ diamonds unbalanced.
1M is usually unbalanced if 1♣ can contain a 5cd major, with 2/1 responses
1NT is 14-16 (15-17 if you don't open light) - regularly with 5cd major.

The unbalanced 1♦ opening makes it easier to handle interference as opener is known to have real diamonds (usually five). In uncontested auction most use transfer rebids by opener over 1M responses, as 1NT isn't needed as a natural bid.
The usually unbalanced 1M opening avoids rebids on non-existing minors over a forcing or semiforcing 1NT response.
The T-Walsh structure (not allowed in ACBL land) makes it easier to find 53-fits in a major when opener is balanced (an option not available after a 1♦ opening); without a 4cd major responder can bid 1♠ as a transfer to 1NT allowing opener to declare.
Most partnerships include some version of the Gazzilli Convention.

This is a basically natural approach which allows you to include a great deal of sophistication if you wish.

There are several variations in use:
- the 1♠ response to 1♣ (transfer to 1NT) contains non-inv hands with no major, stronger balanced hands and either inv+ diamond hands or inv+ club raises (depending on agreements) - 2♣ shows a good hand with the other minor (transfer or natural raise respectively).
- the T-Walsh transfers are accepted either with any hand containing 3cd support (unlimited 3cd accept - forcing) or with less than 16 pts and 3cd support (limited 3cd accept - nonforcing) or with a weak NT [or unbal with 3cd support and comparable strength] (wk bal accept). The latter treatment allows a 1NT rebid with 18-19.
- after 1♣ - 1red - 1NT usually 2♣ is used to show either a weak hand with diamonds or any invite. Some use 2♦ as an artificial game force while others play second-round transfers by responder.
- after 1♥-1♠ and 1M-1NT, a 2♣ rebid (Gazzilli) shows a strong hand or clubs. Some have reversed tne meanings of 2♣ and 2M, showing 5M+4♣ by the latter while the Gazzilli 2♣ rebid shows a strong hand or a 6cd major.
- many play 2M as 9-12 with a 6cd suit (a "not so weak" two) to keep the 1M opening up to strength when used with a one-suiter.
- 2-level jump responses are played as weak by some (ranges vary) and invitational by others - depending on systemic details some use Reverse Flannery responses to 1m openings.

A good structure for a serious partnership IMO.

[The_Badger]

Although this is a discussion about 2/1 bidding, it was strange how the 1♦ opening in Precision became a universal opening for many weak hands, and sometimes only guaranteeing a ♦ suit of 1+ (although I have actually seen it on another player's convention card of 0+ !)

Whilst Precision is completely different to 2/1 as the 1♣ opening is already taken for all 16+ hands, when I went back to playing a variant of 5 card Acol with an intermediate no-trump (14-16), we bid the shorter minor with all weak balanced hands, and the longer one with any weak unbalanced hands. At the time we had a multi 2♦ that covered the 18-19 balanced range as well.

This seemed to work well, but it's something I used over 20 years ago.

[Kapi Blas]

dokoko, on 2017-August-08, 20:43, said:

The following method is becoming popular among experts in the last years:

1♣ 2+ clubs, contains all balanced hands outside the 1nt range (including 5♦332 and - if you wish - 5M332),
responses hereto are T-Walsh (1♦ shows 4+ hearts, 1♥ shows 4+ spades).
1♦ 4+ diamonds unbalanced.
1M is usually unbalanced if 1♣ can contain a 5cd major, with 2/1 responses
1NT is 14-16 (15-17 if you don't open light) - regularly with 5cd major.

The unbalanced 1♦ opening makes it easier to handle interference as opener is known to have real diamonds (usually five). In uncontested auction most use transfer rebids by opener over 1M responses, as 1NT isn't needed as a natural bid.
The usually unbalanced 1M opening avoids rebids on non-existing minors over a forcing or semiforcing 1NT response.
The T-Walsh structure (not allowed in ACBL land) makes it easier to find 53-fits in a major when opener is balanced (an option not available after a 1♦ opening); without a 4cd major responder can bid 1♠ as a transfer to 1NT allowing opener to declare.
Most partnerships include some version of the Gazzilli Convention.

This is a basically natural approach which allows you to include a great deal of sophistication if you wish.

There are several variations in use:
- the 1♠ response to 1♣ (transfer to 1NT) contains non-inv hands with no major, stronger balanced hands and either inv+ diamond hands or inv+ club raises (depending on agreements) - 2♣ shows a good hand with the other minor (transfer or natural raise respectively).
- the T-Walsh transfers are accepted either with any hand containing 3cd support (unlimited 3cd accept - forcing) or with less than 16 pts and 3cd support (limited 3cd accept - nonforcing) or with a weak NT [or unbal with 3cd support and comparable strength] (wk bal accept). The latter treatment allows a 1NT rebid with 18-19.
- after 1♣ - 1red - 1NT usually 2♣ is used to show either a weak hand with diamonds or any invite. Some use 2♦ as an artificial game force while others play second-round transfers by responder.
- after 1♥-1♠ and 1M-1NT, a 2♣ rebid (Gazzilli) shows a strong hand or clubs. Some have reversed tne meanings of 2♣ and 2M, showing 5M+4♣ by the latter while the Gazzilli 2♣ rebid shows a strong hand or a 6cd major.
- many play 2M as 9-12 with a 6cd suit (a "not so weak" two) to keep the 1M opening up to strength when used with a one-suiter.
- 2-level jump responses are played as weak by some (ranges vary) and invitational by others - depending on systemic details some use Reverse Flannery responses to 1m openings.

A good structure for a serious partnership IMO.

I'm playing really similar system right now. I'm not sure if there is any world-class pair that opens 1♣ with 5M332 with 12-14 HCP. Playing Gazzili you can't play forcing NT that normally includes some cool hand types such as 3 card limit raise, opening 1♣ with 5M would solve this problem but again i think it would be hard sometimes to find this 5-3 Major Suit fit after 1♣ opening. If you are playing 2+♣ then 1 Diamond opening is 4441 with singleton♣ or 5+ IMO.

[Kapi Blas]

JLilly, on 2017-August-08, 16:44, said:

In both weak-NT and strong-NT contexts, it seems like the opener of 1m chooses the particular suit based on a "better minor" (or "least bad minor") criterion, when a lot of the time that's not as meaningful a distinction as the hand's shape, and in the case of a balanced hand, whether the 1m opener has a 4cM to raise responder with and what they intend to do after the frequent 1m-1X; 1NT-2om or 1m-1X; 1NT-2m auction (whatever its meaning, as a raise, as checkback, as NMF, etc.).

The most useful information you can tell responder about both ♠Qx ♥x ♦KQJxx ♣AJxxx and ♠KJxx ♥AQxx ♦xxx ♣Kx surely is something other than the fact that your clubs are not longer than your diamonds.

What methods do people play for getting more meaning out of the 1m openings? I've heard "unbalanaced diamonds and balanced clubs" -- do people conceive of methods in terms of "pre-answering" a checkback Stayman from partner after the 1NT rebid on balanced hands? An emphasis on showing or denying 4-card majors? A sort of L-shaped scheme where 1♣ is distributional with clubs OR balanced, and 1♦ is everything else? And for these purposes, is being "balanced" about lacking length? Lacking shortness? Being focused on finding a major fit?

Thanks!

That is how it looks like im my partnership:

1♣ 11-21 with ♣ or 12-14 balanced

Responses:

1♦ transfer 4+♥
1♥ transfer 4+♠
1♠ transfer to NT 6-9 HCP or 12+ HCP balanced or weak with 6+♦ or GF with♦
1NT 10-11 balanced without 4 card major
2♣ 12+ HCP 4+♣ without 4 card major
2♦ transfer to♥ 6+ very weak
2♥ transfer to ♠ 6+ very weak
2♠ GF with 5-5 Minor
2NT GF with any other 5-5 shape


1♦ 11-21 HCP with 4441♣ or 5+ Diamond unbalanced( with 5♦332 12-14 HCP we open 1♣)

Responses:

1♥/♠ 4+ ♥/♠ 6+ HCP, forcing
1NT 6-11 without a 4 card major
2♣ GF with ♣
2♦ 4+-4+ majors, less than invitational
2♥ reversed flannery 4♥ 5♠, weak

Generally we use T-Walsh after 1♣ opening but since we play 2♣ as 18-19 balanced we can use 1NT rebid by opener to show a minimum hand with 6+♣. We play two-way Checkback

[fromageGB]

I am strongly convinced that "balanced club, unbalanced diamond" is a much better approach. My definition of a 1♦ open is any hand that has 6 diamonds or a singleton or void outside diamonds. The definition of a 1♣ open is any hand that cannot open 1♦, or all hands with 6 clubs. This leads to the slightly unexpected result of a {42}52 shape opening 1♣, but it works well. Here in the EBU we now announce a 1♣ with "may be only 2 clubs, and can have 5 diamonds", even if this is a very rare hand type. If no major fit, this hand may choose to play in 2♦ rather than 1NT.

To a 1♦ open with natural continuations, I do play a "natural" 1NT rebid over a major, meaning a 3-suiter short in that major. The 1♦ definition ensures that an opening will be of only 3 types:
- single suited diamonds (6+ card)
- both minors (10 + cards in both suits)
- a 3-suiter.
One of the suits in a 3-suiter may be only a 3 carder, but it is still good to raise a 1M response because even if partner does not have 5, you have 3 with almost immediate ruffs, and you are ruffing in the short trump hand.

However, I do prefer a set of artificial continuations over 1♦ where you bid 1♥ up to 10hcp with either or both majors, and 1♠ with any 11+ (even with no major), as it gets more precise in subsequent hand description.

The 1♣ open is brilliant if you are allowed to play transfer walsh. The opening definition guarantees that you have at least 2 cards in each major, which makes major fits so easy - responder can describe exactly whether a major is 4, 5, or 6 card, and also whether invitational or better, or worse than invitational.

The way I play all major fits can be found this way, without the need for checkback or xyz. After 1♣ 1red 1NT, responder can bid 2♣ to play, or 2♦ to play. Look for a 4-4 major fit, and if not there, escape to a minor if weak. Responder without a 4+ card major starts with 1♠, and weak, invitational (can stop in 2NT), or strong minor hands are covered in that. A direct 3m is also a preempt.

I have no need for Gazzilli after a minor opening, 1♣ then 2♣ being a passable not strong 6+ carder, 1♦ then 2♣ being a passable 2-suiter.

I play 5 card majors 2/1, but there may be some merit in 4 card majors if you are not allowed to play transfer walsh.

[dokoko]

Kapi Blas, on 2017-August-10, 04:39, said:

I'm playing really similar system right now. I'm not sure if there is any world-class pair that opens 1♣ with 5M332 with 12-14 HCP. Playing Gazzili you can't play forcing NT that normally includes some cool hand types such as 3 card limit raise, opening 1♣ with 5M would solve this problem but again i think it would be hard sometimes to find this 5-3 Major Suit fit after 1♣ opening. If you are playing 2+♣ then 1 Diamond opening is 4441 with singleton♣ or 5+ IMO.

Auken-Welland open 1c on a weak 5M332 usually. This is playable, you will sometimes miss a 53-fit but there will also be hands when opps lead up to your 5cd major in 3NT or play in your 5cd major.

There's no reason not to play forcing NT (with or without Kaplan Inversion) together with Gazzilli. In fact with my regular partner we play Kaplan Inversion (1h-1s = 1rd force with less than 5 spades, 1h-1nt = 5+ spades) and 1h-1s-1nt is Gazzilli (clubs or 16+ pts) to save space.

Our 1d is 5+ unbal or 4441 with black singleton (1444 is easier to bid when responder shows spades over 1d than over 1c).

[nullve]

Kapi Blas, on 2017-August-10, 04:39, said:

I'm not sure if there is any world-class pair that opens 1♣ with 5M332 with 12-14 HCP.

Welland-Auken usually open 1♣ instead of 1M with 5M(332) and 11-13/17-19 hcp. So here we have an undeniably WC pair that can open 1M systemically with 11-13, 5M(332) if they want to, but still choose to open 1♣ most of the time. This suggests that opening 1♣ instead of 1M works quite well for them, although I suspect they have systemic reasons for doing so that don't exist in a "standard" T-Walsh system. (E.g. over 1♠-2♣ = like a standard F1 1N response, but with 1- S if < 10 hcp they play

2♦ = "3+ H"
2♥ = "6+ S"
2♠ = "4+ m"

according to their CC, which not only makes the 5233 shape unbiddable but also suggests there will be some violations of Burn's law when Opener has 53(32) and Responder something like 6-9, 13(54).)

Kapi Blas, on 2017-August-10, 04:39, said:

Playing Gazzili you can't play forcing NT that normally includes some cool hand types such as 3 card limit raise, opening 1♣ with 5M would solve this problem but again i think it would be hard sometimes to find this 5-3 Major Suit fit after 1♣ opening.

Outside the ACBL, why risk

1M-1N*
2x**-3M***
P

* F1N
** x<M
*** 3c limit raise

when you're allowed to bid e.g.

1M-2♣*
2♦**-2M ***
P.

* "NAT, BAL or Drury". Forcing to 2M or game (or, alternatively, to 2M, 3♣ or game)
** ART MIN
*** 3c limit raise

?

It's true that you can miss a 5-3 M fit if you open 1♣ with 11-13, 5M(332), e.g. after 1♣-[1M-1]; 1M-1N; P, but that's not a big problem in my experience. And maybe it works for similar reasons that

* opening 1N instead of 1M with 5M(332);
* rebidding 1N instead of 1♠ over 1m-1♥ in standard with 4S4m(32)

work (IMO)?

It should also be mentioned that the same 5-3 H fit can be found after

1♣*-1♦
1♥-2♥
P

* NAT or 11-13/17-19 BAL, incl. 5M(332)
** 4+ H

but missed after e.g.

1♠-1N*
P.

* semi-forcing (or non-forcing)

Kapi Blas, on 2017-August-10, 05:17, said:

Generally we use T-Walsh after 1♣ opening but since we play 2♣ as 18-19 balanced we can use 1NT rebid by opener to show a minimum hand with 6+♣.

If 18-19 BAL is in 1♣, it's possible to use the 1N rebid as a kind of non-forcing lebensohl, as in

1♣-[1M-1]; ?:

(...)
1N = a) "11-13", 2-M6+C and, if M=♥, 3- S b) 18-19 BAL, 2-3 M
...P = 4 M, wants to play 1N opposite b) (and therefore, by bridge logic, opposite a) as well)
...2♣ = to play opposite a)
......P = a)
......2♦-2M = b)
...2♦+: similar to 2♦+ over 1♣-[1M-1]; 2♣, but with a way for Opener to show 18-19 BAL
2♣ = "14-16", 2-M6+C and, if M=♥, 3- S
(...).

[Kapi Blas]

nullve, on 2017-August-11, 03:40, said:

Welland-Auken usually open 1♣ instead of 1M with 5M(332) and 11-13/17-19 hcp. So here we have an undeniably WC pair that can open 1M systemically with 11-13, 5M(332) if they want to, but still choose to open 1♣ most of the time. This suggests that opening 1♣ instead of 1M works quite well for them, although I suspect they have systemic reasons for doing so that don't exist in a "standard" T-Walsh system. (E.g. over 1♠-2♣ = like a standard F1 1N response, but with 1- S if < 10 hcp they play

2♦ = "3+ H"
2♥ = "6+ S"
2♠ = "4+ m"

according to their CC, which not only makes the 5233 shape unbiddable but also suggests there will be some violations of Burn's law when Opener has 53(32) and Responder something like 6-9, 13(54).)


Outside the ACBL, why risk

1M-1N*
2x**-3M***
P

* F1N
** x<M
*** 3c limit raise

when you're allowed to bid e.g.

1M-2♣*
2♦**-2M ***
P.

* "NAT, BAL or Drury". Forcing to 2M or game (or, alternatively, to 2M, 3♣ or game)
** ART MIN
*** 3c limit raise

?

It's true that you can miss a 5-3 M fit if you open 1♣ with 11-13, 5M(332), e.g. after 1♣-[1M-1]; 1M-1N; P, but that's not a big problem in my experience. And maybe it works for similar reasons that

* opening 1N instead of 1M with 5M(332);
* rebidding 1N instead of 1♠ over 1m-1♥ in standard with 4S4m(32)

work (IMO)?

It should also be mentioned that the same 5-3 H fit can be found after

1♣*-1♦
1♥-2♥
P

* NAT or 11-13/17-19 BAL, incl. 5M(332)
** 4+ H

but missed after e.g.

1♠-1N*
P.

* semi-forcing (or non-forcing)


If 18-19 BAL is in 1♣, it's possible to use the 1N rebid as a kind of non-forcing lebensohl, as in

1♣-[1M-1]; ?:

(...)
1N = a) "11-13", 2-M6+C and, if M=♥, 3- S b) 18-19 BAL, 2-3 M
...P = 4 M, wants to play 1N opposite b) (and therefore, by bridge logic, opposite a) as well)
...2♣ = to play opposite a)
......P = a)
......2♦-2M = b)
...2♦+: similar to 2♦+ over 1♣-[1M-1]; 2♣, but with a way for Opener to show 18-19 BAL
2♣ = "14-16", 2-M6+C and, if M=♥, 3- S
(...).

You're making some good points here. The only thing is about this sequence:


1M-2♣*
2♦**-2M ***
P.

* "NAT, BAL or Drury". Forcing to 2M or game (or, alternatively, to 2M, 3♣ or game)
** ART MIN
*** 3c limit raise


2♣ as a Nat, Bal or Drury obviously makes sense to me. The first thing is why would you like 2♦ a minimum and not 4+♦? The second thing is if u use 2M in this sequence as limit raise you must bid GF hands with 3 card fit as 3M I suppose, that's a lot of wasted bidding space when you are propably seeking slam or something.

[nullve]

Kapi Blas, on 2017-August-12, 07:59, said:

The first thing is why would you like 2♦ a minimum and not 4+♦? The second thing is if u use 2M in this sequence as limit raise you must bid GF hands with 3 card fit as 3M I suppose, that's a lot of wasted bidding space when you are propably seeking slam or something.

2♦ as 4+ D is part of a competing "standard" scheme where Opener rebids 2M over 1M-2♣ to reject the invitiation with 3c M support. Maybe that's better.

I play

1M = "10-21, 5+ M, unBAL"

1M-2♣; ?:

2♦ = "10-12"
...In one partnership:
...2M = the 3c limit raise
...2OM = GF relay
......2♠(M=♠): idle!
......2N+ = relay structure
...4M = to play
...other = GF, 5+ C, unBAL
...nullve-nullve:
...2♥(M=♥) = the 3c limit raise
...2♥(M=♠) = Multiinvite (incl. the 3c limit raise)
...2♠ = GF relay, not very unBAL unless M SUPP
......2N+ = relay structure
...4M = to play
...other = GF, 5+ C, (very) unBAL
2♥+ = "13-21", i.e. GF.

[JLilly]

If T-Walsh is disallowed (thanks, ACBL!), what do you recommend be done with the 1♦ response to 1♣? The GCC lets it be "artificial and forcing". Of course this presumably affects the entire response structure. . .

Some possibilities off the top of my head:
1) 1♦ is Stayman-like, asking opener to rebid 4-card majors. Direct response of 1M by responder promises 5 cards. It may be useful to interchange the standard spades and NT responses after opener's 1♥: Responder's 1♠ rebid shows 4 spades and 3- hearts, which allows opener to declare 1NT; responder's 1NT rebid shows 5 spades and 4 hearts, which opener will pull as appropriate.
2) Weak (6~9 HCP) transfer to 1NT with no 4-card major OR unbalanced with diamonds. 1M response shows 4+; direct 1NT response is stronger 10~11 HCP. Opener bypasses the transfer with the unbalanced club hand or the strong balanced hand.
3) Either zero 4-card majors or both 4-card majors. With 4 hearts, opener bids 1♥, with responder rebidding 1♠ with zero 4-card majors to transfer to 1NT, allowing opener to declare. If opener has 4 spades and not 4 hearts, they bid 1♠ and the transfer-to-1NT trick doesn't work. This also precludes the responder rebidding 1♠ over 1♥ to show 5 spades and 4 hearts. At this point, might as well use a proper relay system, I guess.

Speaking of what's allowed by the GCC, 1C and 1D are allowed to be "an all-purpose opening bid (artificial or natural)". Presumably this allows something like "1♦ promises 3+ diamonds unbalanced (however defined), and 1♣ is everything else", which these coded-minor systems are.

fromageGB, on 2017-August-10, 15:16, said:

My definition of a 1♦ open is any hand that has 6 diamonds or a singleton or void outside diamonds. The definition of a 1♣ open is any hand that cannot open 1♦, or all hands with 6 clubs. This leads to the slightly unexpected result of a {42}52 shape opening 1♣, but it works well.

So a {4-1}=3=5 hand is a 1♦ opening, right?

Helene, thanks for the link

[Kapi Blas]

nullve, on 2017-August-12, 11:30, said:

2♦ as 4+ D is part of a competing "standard" scheme where Opener rebids 2M over 1M-2♣ to reject the invitiation with 3c M support. Maybe that's better.

I play

1M = "10-21, 5+ M, unBAL"

1M-2♣; ?:

2♦ = "10-12"
...In one partnership:
...2M = the 3c limit raise
...2OM = GF relay
......2♠(M=♠): idle!
......2N+ = relay structure
...4M = to play
...other = GF, 5+ C, unBAL
...nullve-nullve:
...2♥(M=♥) = the 3c limit raise
...2♥(M=♠) = Multiinvite (incl. the 3c limit raise)
...2♠ = GF relay, not very unBAL unless M SUPP
......2N+ = relay structure
...4M = to play
...other = GF, 5+ C, (very) unBAL
2♥+ = "13-21", i.e. GF.

I play this way in this sequence:

1M - 2♣
?

2♦- 4+ diamonds
2♥- 4+ hearths, or no other viable bid if opener bid ♥
2♠- 4+ spades, or no other viable bid if opener bid ♠


And now:

1M - 2♣
2♦ - ?

2M - 15+ with 3 card fit
2 in the other major - 12+ with clubs, denies fit, relay
2NT - 12+ balanced, relay
3♣ - 15+ single suited hand with clubs, denies fit, relay
3M - 12-14 with 3 card fit

[nullve]

JLilly, on 2017-August-13, 00:02, said:

If T-Walsh is disallowed (thanks, ACBL!), what do you recommend be done with the 1♦ response to 1♣? The GCC lets it be "artificial and forcing". Of course this presumably affects the entire response structure. . .

The GCC allows

1♣-?:

1♦ = 4+ S. May have longer H unless GF*
...E.g.:
...1♥ = 3(+) S OR 11-13 BAL, 2-3(4) S
......E.g.:
......1♠ = 4+ H
......1N = NAT NF
......2♣+ = XYZ
...1♠ = 4+ H, unBAL
...1N+ = similar to 1N+ over 1♣-1♥ in "Swedish" T-Walsh (where the 1N rebid is 17-19 BAL, 2-3 S)
1♥ = 4+ H. 3- S unless GF.
...E.g.:
...1♠ = 3(+) H OR 11-13 BAL, 2-3(4) H**
......E.g.:
......1N = NAT
......2♣+ = XYZ
...1N+ = similar 1N+ over 1♣-1♦ in "Swedish" T-Walsh (where the 1N rebid is 17-19 BAL, 2-3 H)
1♠ = GF relay
1N = NAT NF,

which is similar to the kind of T-Walsh that Welland-Auken play.

* Or you can play Flannery by Responder (instead of Reverse Flannery by Responder, which makes more sense in a standard or T-Walsh context)
** This is why the 1♥ response denies 4+ S unless GF.

[fromageGB]

JLilly, on 2017-August-13, 00:02, said:

So a {4-1}=3=5 hand is a 1♦ opening, right?

Certainly. Playing natural continuations and not strong, you rebid 1NT over 1♥, which shows a 3-suiter short in hearts, so responder can bid 2-anything to play. If responder bids 1NT (no 4 card suit other than clubs), you bid 2♣.

[blackshoe]

If I'm not mistaken, T-Walsh will be allowed in the ACBL under the upcoming Yellow chart. Assuming it all gets approved.