[yunling]

In the past few years mexican 2D(or 2C)has become more and more popular among top players, if my observation is right.
I used to be against it, but a few analysis shows that 2NT opening is a big winner versus natural 1 minor, and probably also a winner versus precision 1C.
So now I wonder if bid to 2 level quickly with a strong balanced hand is theoratically very sound?
It just prevents opponents from making a cheap overcall which matters much more than staying in 1NT or slam auction.
This also applies to meckwell 1C-2D 8-10 balanced sequence which now I believe is better than putting 8-10 balanced into 1D or 1H——I lost in a few occasions when fourth seat was able to overcall.

[johnu]

yunling, on 2026-March-14, 23:08, said:

In the past few years mexican 2D(or 2C)has become more and more popular among top players, if my observation is right.

2♦ has never been popular among top players, and has become even less popular in recent years IMHO. On the other hand, Multi 2♦ has become very popular.

yunling, on 2026-March-14, 23:08, said:

I used to be against it, but a few analysis shows that 2NT opening is a big winner versus natural 1 minor, and probably also a winner versus precision 1C.

What analysis is this that show 2NT is a big winner versus starting lower? A common description of a 2NT opener is slam killer, the implication being that starting the auction at the 2NT level doesn't leave room to explore for slam at a lower level.

[mw64ahw]

Possibly someone taking a contrarian position for discussion sake?

A Weak NTer in Shenzhen also feels like a bit of an anomaly.

[DavidKok]

My impression is that putting strong balanced in 1♣ is a significant winner.

I think the reason some players prefer an artificial 2♣ or 2♦ showing 18-19 bal is that this hand type can have a hard time in standard after interference. There's significant extras after the opening, but no great suit to bid. Splitting it out of the opening relieves takeout doubles in competition and permits more shape-based bidding. In return, you lose a 2-level opening bid for other uses and you can no longer resolve the big balanced hand at the 1-level, which plenty of other systems can.
Precision faces other tradeoffs as the 17-19 balanced range is the 'default' responder assumes in competition. There's not much pressure to act with that hand type. I don't think this combination is a good idea. You could split out e.g. 20-21, but I prefer not to.

Using 1♣-2♦ to show a minimum positive balanced hand is a fine idea, though in general the positive system to a strong 1♣ won't have a large impact on your score.

[PrecisionL]

I have used Rodwell's 1♣ - 2♦ as balanced hands (including 5332) for 10 years now with good results.

Recently we have put all the balanced hands in 1M.

1♣ - 1♥ = Positive (a) 5+ Spades or (b) 11+ Balanced. 1♠ is the relay and 1NT = 11-13, 2♣ = 5+♠, 2♠ = 14+ Balanced.
1♣ - 1♠ = Positive (a) 5+ Hearts or (b) 8-10 Balanced. 1NT is the relay and 2♣ is the Heart hand.

Playing 2/1 I prefer:

2♣ Opener is (18)19-21 Balanced hand with 2♦ Response = 0-5 hcp
2♦ Opener is the 22+ Balanced or 4-loser hand with 2♥ = 0-1 Control

[foobar]

PrecisionL, on 2026-March-16, 11:48, said:

I have used Rodwell's 1♣ - 2♦ as balanced hands (including 5332) for 10 years now with good results.

Recently we have put all the balanced hands in 1M.

1♣ - 1♥ = Positive (a) 5+ Spades or (b) 11+ Balanced. 1♠ is the relay and 1NT = 11-13, 2♣ = 5+♠, 2♠ = 14+ Balanced.
1♣ - 1♠ = Positive (a) 5+ Hearts or (b) 8-10 Balanced. 1NT is the relay and 2♣ is the Heart hand.

Playing 2/1 I prefer:

2♣ Opener is (18)19-21 Balanced hand with 2♦ Response = 0-5 hcp
2♦ Opener is the 22+ Balanced or 4-loser hand with 2♥ = 0-1 Control

Actually, I recently doubled down on that idea and even added a split range, so:

1♣:
...2♦: 8-11/15+ balanced -> symmetric with 2♠
...2♠+: 12-14 balanced, includes 4♥4m32, 5m332, 4♥333, 4m4m

Note that this only includes 5m332 because there simply isn't enough space to handle all the hand types. In fact, we can't fit in even all 4432, 4333 and 5m332, so there-in lies a small tweak to make it work. Basically, 1♣ - 1♥ is 4+♠ and includes the ♠ canape hands, the balanced 4♠332 and the 5+♠ hands.

Now, after 1♣ - 1♥ (4+♠) - 1♠ ® - 1N is the balanced or canape with the minors, so over 1N:
......2♦: 8-11/15+ balanced -> symmetric with 2♠
......2♥: Canape with one ♣ -> join 2N+
......2♠: 12-14 balanced, only includes 4♠4m32 and 4♠333
......2N+: Symmetric two-suited, high short with diamonds

The tradeoff was having to bundle the 5M332 in the single suited scheme, but the nice part is that it's the same GFR over the 1M opening.

[PrecisionL]

Interesting foobar!
We tried a very similar design 10 years ago and liked it very much.
Our new design (Major Positives or balanced) were an attempt to ease the memory. No conclusions at this early stage.

[foobar]

PrecisionL, on 2026-March-17, 17:56, said:

Interesting foobar!
We tried a very similar design 10 years ago and liked it very much.
Our new design (Major Positives or balanced) were an attempt to ease the memory. No conclusions at this early stage.

Note that it's the exact same scheme over the 1D opening (only two hand types with 11-13 balanced OR 4M with minor canape hands).

1D - 1N (GFR):
....2C: Major + Clubs /5m4M40, then follow 2H+
....2D: 5m322 + balanced with spades
....2H: D+S
....2S: 4H4m32 or 4H333 (5m4M40 via 2C)
....2N+: Two suited, high short with D+H

Note that 4M441 are systemically opened 1M, which now allows them to be part of the same 1C - 1M response.

In all, every single opening from 1C through 2D uses the exact same relay scheme.

[blackshoe]

Romex, whence "Mexican 2♦" comes, currently has, for strong balanced hands:

19-20 HCP, 6 controls: open 1NT (artificial, forcing), rebid 2NT
21-22 HCP, 7 controls: open 2♦ (artificial, forcing, may include an unbalanced GF with primary diamonds), rebid 2NT
23-24 HCP, 8 controls: open 2♣ (artificial, forcing), rebid 2NT
25-26 HCP, 9 controls: open 2NT (Game forcing) OR open 2♣, rebid 2♥ then 2NT over partner's forced 2♠ (Birthright)
27-28 HCP, 10 controls: open 2♦, rebid 3NT (not forcing, but if responder bids again, that's forcing to game or 4NT).
29-30 HCP, 11 controls: open 2♣, rebid 3NT (not forcing, but if responder bids again, that's forcing to game or 4NT).

When playing Birthright, the 2NT opening is artificial, weak, preemptive in either minor where that is legal, or in clubs only where "either minor" is not legal.

Rosenkranz found the control requirement to be key in assessing slam possibilities.

[johnu]

blackshoe, on 2026-March-20, 08:41, said:

Romex, whence "Mexican 2♦" comes, currently has, for strong balanced hands:

19-20 HCP, 6 controls: open 1NT (artificial, forcing), rebid 2NT
21-22 HCP, 7 controls: open 2♦ (artificial, forcing, may include an unbalanced GF with primary diamonds), rebid 2NT
23-24 HCP, 8 controls: open 2♣ (artificial, forcing), rebid 2NT
25-26 HCP, 9 controls: open 2NT (Game forcing) OR open 2♣, rebid 2♥ then 2NT over partner's forced 2♠ (Birthright)
27-28 HCP, 10 controls: open 2♦, rebid 3NT (not forcing, but if responder bids again, that's forcing to game or 4NT).
29-30 HCP, 11 controls: open 2♣, rebid 3NT (not forcing, but if responder bids again, that's forcing to game or 4NT).

When playing Birthright, the 2NT opening is artificial, weak, preemptive in either minor where that is legal, or in clubs only where "either minor" is not legal.

Rosenkranz found the control requirement to be key in assessing slam possibilities.

I have the Rosenkranz Romex book stored away in a box in the basement. I don't remember the control requirements for balanced hands (maybe because I never played any part of Romex). For example what do you open with 21 HCP and only 6 or fewer controls if 2♦ is supposed to show 7 controls?

As far as controls in balanced hands go, George also invented CONFI and Super CONFI to investigate the total number of controls held, as well as finding good 8 card fits for play 6 of a suit instead of 6NT.

[blackshoe]

johnu, on 2026-March-20, 19:11, said:

I have the Rosenkranz Romex book stored away in a box in the basement. I don't remember the control requirements for balanced hands (maybe because I never played any part of Romex). For example what do you open with 21 HCP and only 6 or fewer controls if 2♦ is supposed to show 7 controls?

There is not just one "Romex book", there are about half a dozen. The earliest was published in IIRC 1968, the latest in the early 2000s.

With one fewer control and a minimum, open one step less, so in your example case, 1NT, planning to rebid 2NT. If you have a maximum in HCP you do not downgrade the hand because you lack a control.

johnu, on 2026-March-20, 19:11, said:

As far as controls in balanced hands go, George also invented CONFI and Super CONFI to investigate the total number of controls held, as well as finding good 8 card fits for play 6 of a suit instead of 6NT.

Yes he did, and CONFIT (which is what Rosenkranz called it) was included in early versions of the system, but was later abandoned.

[bluenikki]

blackshoe, on 2026-March-23, 01:29, said:

Yes he did, and CONFIT (which is what Rosenkranz called it) was included in early versions of the system, but was later abandoned.

CONFI is what he called it in the first two books. It was brilliant, producing smooth auctions. My wife and I used it also after one of a suit, initiated by 2NT, and after weak NT, initiated by 2♠.

I asked him in 1984, I believe, why he abandoned it. I did not understand his answer.

[awm]

Rosencranz must've been great at rubber bridge, given that he built a system with so many calls dedicated to hands of 20+ HCP. I feel like my partnership averages less than one of these per session, not nearly enough to devote four artificial forcing bids to them!

There are a number of somewhat old fashioned methods (I'd include the original Blue Team Club, as well as Romex) where the idea was to respond to a strong opening by showing controls, then look for fit later. The modern trend has swapped these, focusing on fit first and then controls later. In principle you might think that this doesn't matter, but there are several reasons that very few modern players use the controls-first style:

1. If opponents jump into the auction (and modern opponents do this much more aggressively) you'll be better off if you have some shape information.
2. Having some idea of fit lets you decide how high you can afford to bid (can you commit to 4♠ or might you need to play 3NT) as well as how many controls you need (far fewer if you're looking at three small opposite partner's singleton). This lets you decide whether to even bother asking for controls on some auctions, whereas you always need to find out shape since you can make slam on 26 hcp (or even less) on a good mesh.
3. You probably want a more optimised encoding of shapes than just "natural bidding throughout" and you might also want to try to make the stronger hand declare in your most likely strains, and both of these are easier if you start with shape showing (since you can use the same bids to show the same shapes and then do controls by steps, rather than starting with controls by steps and then having different sequences to show the various shapes depending on how high you ended up after the control-showing response).

[johnu]

bluenikki, on 2026-March-23, 06:34, said:

CONFI is what he called it in the first two books. It was brilliant, producing smooth auctions. My wife and I used it also after one of a suit, initiated by 2NT, and after weak NT, initiated by 2♠.

I asked him in 1984, I believe, why he abandoned it. I did not understand his answer.

Also, CONFI (and Super CONFI) is the name Rosenkranz used in his series of Bridge World articles in 1975.

For the uninitiated, the premise was the with less than 10 controls (Ace = 2, King = 1), a small slam with 2 balanced or semi-balanced hands was likely to be at best on a finesse (or down off the top if AK was in the same suit). E.g. Missing 3 kings, you need 2 out of 3 finesses (50%), or missing an ace, plus a king in another suit, need that finesse or else you are down off the top.

The other cornerstone was that 6 of a suit with an 8 card suit (usually 4-4) often played better than 6NT when holding less than 33 HCP. And a slam killer was having a weak trump suit fit that had a secondary loser, e.g Axxx opposite Kxxx, or AQxx opposite xxxx, etc.