[ali quarg]

Another option http://www.bridgematters.com/idea3.htm if you're OK to play 1NT as forcing

[nullve]

I play a mixture of Gazzilli and transfers over 1♠("10-21, 5+ S, unBAL")-1N("5-12, NF"):

P = "10-12, 5S3-H" (would reject a game invite in notrump)
2♣ = "10-15, 4+ H (a 2-under transfer) OR 16-18, any"
...2♦ = "8+, most hands, GF opposite 16-18"
......2♥ = "10-12" (would reject a game invite in hearts)
......2♠ = "13-15" (would accept a game invite in hearts)
......2N+ = "16-18, RS"
...2♥ = "5-7, PREF opposite 5S4H" OR "8-10, 1-S3H"
......P = "10-15, 4+ H"
......2♠ = "16-18, 3- H, most hands"
......2N = "16-18, 4+ H"
.........3m = 3H5+m1-S, NF
.........(...)
......(...)
...2♠ = "5-7, PREF opposite 5S4H" OR 5-7 TP, 3(4) S
...2N+ = "5-7, usually 1-S2-H, NAT"
2♦ = "13-15, 5S4+m3-H" (Muiderberg 2♠-like)
...2♥ = 5+* H, NF
......P = 2-3 H
......2♠ = 1- H
...2♠ = to play
...2N = GF relay
...3♣ = P/C
...(...)
2♥ = "13-15, 6+S3-H" (a 1-under transfer)
2♠ = "10-12, 6+S2-H"
2N+ = "19-21, RS"

where RS is my usual home-grown relay structure.

Spoiler

A variation based on

1♠-1N; ?:

P/2♣/2N+: as above
2♦ = "10-15, 6+ S" (another 2-under transfer)
...2♥ = range ask
......2♠ = would reject a game invite in spades
......2N+ = would accept a game invite in spades
...2♠ = to play
...(...)
2♥ = "13-15, 5S4+m2-3H"
2♠ = "13-15, 5S4+m1-H"

might be prettier, but would sometimes leak more info. Compare

1♠-1N; 2♦("13-15, 5S4+m3-H")-2♠; P

and

1♠-1N; 2♥("13-15, 5S4+m2-3H")-2♠; P / 1♠-1N; 2♠("13-15, 5S4+m1-H")-P

.

One idea behind this is to avoid 2N and unLawful 3M contracts as much as possible and have auctions such as

a) 1♠-1N; P
b) 1♠-1N; 2♣-2♦; 2♥-P or 1♠-1N; 2♣-2♦; 2♥-2♠; P
c) 1♠-1N; 2♥-2♠; P

instead of the standard auctions

d) 1♠-1N; 2m-2N; P
e) 1♠-1N; 2♥-2N/3♥; P
f) 1♠-1N; 2♠-2N/3♠; P,

respectively.

* The one thing I like about original Bart is being able to separate weak 2-S6+H from weak 2S5H hands at the two-level after 1♠-1N; 2♣. To do something similar without Bart I use the Ambra-like

1♠-2♦ = "hearts"
1♠-2♥ = "diamonds or (in my case an extremely) weak raise"

and include some weak hands with 6+ H (especially those with 1- S, which can be a nightmare after 1♠-1N; 2♦-2♥; 2♠(1- H)) and invitational hands with 5+H2S in the 2♦ response as well. Then over 1♠-2♦; 2♥(NF),

P = weak w/ 6+ H
2♠ = INV w/ 2S5+H, NF
(...)

.

[mw64ahw]

ali quarg, on 2022-December-18, 02:57, said:

Another option http://www.bridgematters.com/idea3.htm if you're OK to play 1NT as forcing

Some interesting ideas here and from nullve.
Some notes

• I like the idea of being able to stop in 2♣ which of course isn't possible with Gazzilli.
• Personally I don't have an issue with stopping in 2NT rather than 2M; after all it scores better than 2M assuming equal tricks.
• Bids like 1♠-2NT as 6+♣ GI or Jacoby 2NT work well if 3♣ shows a minimum for both.
• The same principle as above for 2/1 bids also works well for me.
• I can continue to use 1♠-3♣/♦ as GI or mixed raises.
• I don't think transfers over 1♥ add as much if you play KI.
• Forcing vs semi-forcing NT for me is a toss up between going down in 1NT if responder is weak versus finding a decent fit.
• There only seems to be the space for opener to show strong hands and 2nd suits for 2 of the other suits over 1NT if I want to be able to stop in 2♣. My proposal would be to use 2♦ as ♥ or strong ♣ and 2♥ as 6+♠ or strong ♥. Opener's 2NT is then GI and higher bids are GF. 1♠-1NT-2NT then shows either the GI balanced hand or strong ♦.
• Opponents Xing a transfer could work well over 1♠-1NT-2♥ when opener is strong. Playing a full range of transfers over 1♠-1NT would deter Xing.

Any other thoughts?

[DavidKok]

• Giving up on 1NT but trying to stop in 2♣ sometimes seems backwards to me. Voluntarily stopping in 2-of-a-minor is a bit of a parlay bet anyway - you need to not make 9 tricks, not make 8 in notrump, and the opponents need to not have a profitable sacrifice. It also tends to eat into the allocation of the cheapest bids, so you pay for it on every auction that doesn't stop in 2m.
  
• 2NT and 2M are wholly different beasts, I would not be eager to give up stopping on 2M on even just a few auctions. I don't know how often this is relevant, maybe it is just in one or two infrequent sequences, but it's still a significant cost.
  
• You also need the strong answers to be compatible. If your J2N structure includes, say, a 3♠ rebid showing a minimum with a singleton somewhere (guess what, it's almost always clubs) that might be an issue. You are also exposing yourself to interference.
  
• I imagine this works better on 2/1 sequences, although the interference issue is greater here.
  
• -
  
• -
  
• There's a lot more to it in my opinion, and this choice can have significant consequences for the rest of the system. I've observed that bidding theorists tend to prefer a forcing notrump, possibly to fit in more sequences (which means you need more bidding theorists).
  
• I am not at all a fan of these multi-way bids. Quite frequently they end up slaving partner to the simple reply so we can clarify which type we have, and the cooperative bidding starts one level higher than normal. If you have a detailed set of answers for breaking the transfers that would probably help a lot. And again, multi-way bids expose you to interference.
  
• Doubling artificial low level bids tends to be a suckers game, voluntarily increasing the space for the opponents' side. Generally you can just play 'system on' here, or some simple response scheme making use of redouble and (forcing) pass.

[mw64ahw]

DavidKok, on 2022-December-29, 18:04, said:

3. You also need the strong answers to be compatible. If your J2N structure includes, say, a 3♠ rebid showing a minimum with a singleton somewhere (guess what, it's almost always clubs) that might be an issue.

Yep this one is providing me with a challenge. I guess that 3NT and 4♣ become unusable in a J2N context. With the version I use this impinges on some of the slam-bidding. I'm also not sure how the standalone GI bids normally progress. Does opener usually blast to 3NT/4♣ or are there potentially ♦ and ♥ stopper requests on the way through? Something to simulate further.

This issue seems to pervade all of the 2-way bids when a transfer break may be invitational in the weak suit. i.e. 1♠-1NT-2♦-2NT as an invitational raise in ♥ or perhaps both minors. Constructing these follow-ups makes the bidding more complex.

[DavidKok]

Rather than 'more complex', I think 2-way bids are usually just inferior to 1-way bids because of this issue. In my experience they only work well in very specific situations. The simple (and boring) 2-way bids are all just split range with the same shape, because responder's hand will evaluate the same opposite those regardless.

[mw64ahw]

Started some simulations.
The first hand was exactly as above with a 3♠ bid required showing a minimum and short ♣ so as to be in the optimum makeable contract rather than 3♣

[mw64ahw]

I've played around with a few simulations given the proposed structures above and come up with a couple of further options.

The key elements in these options are:

• 2/1 bids are game invitational rather than game forcing
• semi-forcing NT with all Weak balanced hands passing. Good 14+ balanced hands should be are included in the 15-17 NT
• responder doesn't usually play in 1NT with a long weak suit with the exception of ♣
• responder doesn't usually play in 1NT with 9-10 and any long weak suit
• openers game invitational bids in a 2nd suit are shown via 2NT rather than using the Gazzilli approach and stopping in 2M. 3♣ by responder now becomes a game force.
• opener's game forcing bids are shown via 3♣ and higher bids that describe shape
• ♠ support bids are as comprehensive as I can get with regards to strength
• transfer breaks have been simulated with reasonable results which appear to help in slam bidding (details not included)

1st Option: Responses after 1♠ opening

• 1NT 6-10
• 2♣ 3+♣ 11+ or 3+♣3♠ GF or 6+♦ Weak or 6+♦ 9-10
• 2♦ 5+♦ 11+ or 2♣3+♦3♠ GF or 6♥ Weak or 6+♥ 9-10
• 2♥ 5+♥ 11+ or Constructive 3+♠ or 3♠ Limit Raises
• 2♠ 3/4♠ Pre-emptive
• 2NT 4+♠ Limit+
• 3♣ 6+♣ 9-10
• 3♦ Stronger 4+♠ mixed raises
• 3♥ Weak 4+♠ mixed raise
• 3♠ Pre-emptive
• 3NT 13-16 (3433)
• 4♣ SI ♣ void
• 4♦ SI ♦ void
• 4♥ SI ♥ void
• 4♠ Pre-emptive

Rebids after 1NT response

• Pass Balanced 11-13/14
• 2♣ 4+♣ 17+ or 4+♦
• 2♦ 4+♦ 17+ or 4+♥
• 2♥ 4+♥ 17+ or 6+♠
• 2♠ 5+♠ 4+♣
• 2NT 18-19
• 3!♣ good 5+♣♠ 14-16
• 3♦ good 5+♦♠ 14-16
• 3♥ good 5+♠♥ 14-16
• 3♠ good 6+♠ 14-16
• 3NT 18-19 no weak doubleton

With 2♣-2♥ after responder has shown a preference 2NT now shows the game invitational hand while higher bids are game forcing and show shape.


2nd Option
This follows the broad structure above with the following exceptions

• Responder may stop in 2♣ as in http://www.bridgematters.com/idea3.htm
• 1♠-1NT-2♠ now shows 5+♣♠ as in http://www.bridgematters.com/idea3.htm
• 1♠-1NT-2NT is either 17+ 5♠4+♦ or 5323 18-19 with a weak ♦ doubleton
• 1♠-1NT-2♦ now shows ♣ as the strong option or 5332 18-19 with a weak doubleton
• 1♠-1NT-2♥ now shows ♥/♠ as the strong option or 5232 18-19 with a weak doubleton

[DavidKok]

Sorry, I don't get it. Quite a few of those key elements sound like weaknesses? 2/1 is no longer GF so you lose accuracy on game auctions, responder's game force starts at the 3♣ level, opener starts showing shape with GF hands at the 3♣ level, the first round bids contain many different hand types both in terms of shape and strength so you're vulnerable to interference. What are the benefits of this approach?

[mw64ahw]

DavidKok, on 2023-January-01, 15:26, said:

Sorry, I don't get it. Quite a few of those key elements sound like weaknesses? 2/1 is no longer GF so you lose accuracy on game auctions, responder's game force starts at the 3♣ level, opener starts showing shape with GF hands at the 3♣ level, the first round bids contain many different hand types both in terms of shape and strength so you're vulnerable to interference. What are the benefits of this approach?

I guess the best way to test the structure is to try it in practice rather than just simulate since at the moment this is just an academic exercise

Your points

a) 2/1 GI vs GF is a question of style. As you are aware there are benefits to GI. At least with GI you can exclude any balanced hand rather than having a 13-14 balanced hand sitting there with a semi-forcing NT
b) With Gazzilli I guess opener doesn't get to show their 2nd suit with 17/18 and responder not showing 8+.If they do then its at the 3-level? In option 1 you know both the strength and the 2nd suit at 2NT. I've seen hands where having this definition will get you to 3NT with less than 8hcp if you apply the correct judgement
c) Responder can GF after a 2NT response knowing both opener's precise strength and 2nd suit so:
1♠-1NT
2♥-2♠
2NT shows 17/18 5+♠4+♥xx - 3♣ (as an option) then asks opener to define further, say
--3♦ <Default>
---- 3♥ asks 55xx, 5422 etc.?
--3♥ 5413
--3♠ 64xx
--3NT 5431
--4♣5404
--4♦5440
--4♥ 6♠5♥
If you can't place the contract from there then this is not the approach for you

d) You are correct that responder's bid can be subject to interference, more so with the weak option. However, I don't think this is any different from any other approach where you may get interference. With interference your methods change. The benefit is that you don't get stuck in 1NT with a long minor suit and weak when opener passes. The bid in the weak case is also more pre-emptive than 1NT where something like a Vasilevsky defence can be applied. And woe betiede opponents who X when you have the stronger options. I do run simulations with and without interference and defence becomes trickier with the mulri from my limited perspective.

1♠-P-2♦ ♣ interference is now at the 3[level]
1♠-P-1NT-X as ♣

[DavidKok]

The issue with interference on multi-way bids is that is can be difficult for opener to evaluate their hand without a clear cue on what responder might have. For example, on the first option 1♠-(P)-2♥-(3♦); <some bid>-(4♦) might be problematic since opener doesn't know about support, and might not have a safe bid over 3♦ if partner has hearts, while responder can't safely bid at the 4-level over what is potentially a minimum. The more the weak and strong options differ in shape the worse this problem is (the 2♣ response in particular is vulnerable to this).

[mw64ahw]

DavidKok, on 2023-January-01, 17:49, said:

The issue with interference on multi-way bids is that is can be difficult for opener to evaluate their hand without a clear cue on what responder might have. For example, on the first option 1♠-(P)-2♥-(3♦); <some bid>-(4♦) might be problematic since opener doesn't know about support, and might not have a safe bid over 3♦ if partner has hearts, while responder can't safely bid at the 4-level over what is potentially a minimum. The more the weak and strong options differ in shape the worse this problem is (the 2♣ response in particular is vulnerable to this).

I think you have plenty of options here:
Pass - partner will bid ♠ with 3+ (possibly passing VN with a weak constructive bid), X for penalty, bid 3♥ with 6♥ or 3NT with a GF hand and ♦ stopper
X Penalty without ♥
3♥ 5+S♠3+♥ enough for 3♠ or GF ♥
3♠ 5+S♠3+♥ GF in either contract
3NT ♦ stopper with 17+
4♦ SI in either contract
4♠ self-sustaining suit