[antonylee]

Hi,
I've recently started looking around Mexican 2♦ (trying to find ideas to rearrange my NT structure should I switch to 11-13-NT, e.g. 11-13=1N, 14-16=1m..1N, 17-19=2♦) (of course I could switch to prepared 1m openings but that's not the point here).
It seems that most response systems use some artificial 2♥&2♠ to ensure right-siding of the contract, but is that really optimal? What about something simpler such as
2M, 2N = to play [or possibly: 2N = some minor(s) oriented scramble / minor(s) strong hand]
3♣ = puppet
3♦♥ = invitational transfer
3♠ = transfer to 3N

True, we wrong-side 2M and 2N but assuming we're in a field where most people play standard, their auction is likely going to be:
- in the 2M case: 1m-1M-2N-P/3M/some sort of signoff; so they've wrong-sided too and they're one level higher;
- in the 2N case: 1m-P ??? and now the opponents are in.
And, much more importantly, we get to play in 2♥, which more artificial schemes do not seem to allow (I believe).

Is the right-siding issue really more important than the ability of signing off in 2♥?

[blackshoe]

What hand types are included in the 2♦ opening?

As I first learned this convention, 2♦ was one of:

1. Balanced 21-22 HCP with 7 controls (and hands might be adjusted upwards or downwards based on the number of controls).
2. Unbalanced GF with primary diamonds (might have a second 4+ card suit).
3. Unbalanced GF, three suited, unspecified singleton.
4. Rarely, Balanced 27-28 HCP with 10 controls.

The responses were simple:

2♥: 0-4 HCP
2♠: 5-10 HCP (FG)
2NT: 11+ HCP (slam is probable).

Opener would then show his hand type.

The latest version, 2♦ does not include the three suiters. Responses are based on the assumption that open will have the first hand type (a bit more than a 75% chance), and attempt to "right side" the contract as often as possible. So the responses are a bit more complicated:

Pass: a yarborough with a long diamond suit.
2H: 0-9 HCP, no slam interest opposite 21-22 balanced, < 4 hearts
2S: 10+ HCP, 3+ controls (usually), slam interest
2NT: transfer, 0-3 HCP, 6+ clubs, no 4 card major, or possibly a major two suiter
3C: special Stayman, at least 4-4 in the majors and only game interest.
3D: transfer, 0-9 HCP, exactly 5 hearts, < 4 spades.
3H: transfer, 0-3 HCP, 5+ spades, < 4 hearts, signoff
3S: balanced game only hand, exactly 4 hearts, < 4 spades
3NT: at least 5-5 in the majors, game interest only
4C: 6+ hearts, to play in 4 hearts
4D: 6+ spades, to play in 4 spades

[antonylee]

A priori I only need strong balanced right now, though squeezing in some extra hand types is always welcome.

[Free]

It depends on what you want. Playing 2M/NT as natural signoff basically means you want to use your regular 2NT structure for 3♣+ responses. Note that you've lost some bidding space already by not opening 1m, so partner will have a lot less information. That's why it seems sensible to try and get as many hands as possible across.

The way L-V play:
- they are still able to signoff in 2♠ (and rightside this btw)
- they can rightside 2NT
- they can describe many hand types
- they can signoff in 3♣ (and rightside ♣ for stronger hands)
- they can show minor 2-suiters below 3NT
- ...
The only thing you gain by playing 2M/NT natural NF is that you are able to play 2♥ while they have to play 3♥. Compared to all the good and more frequent stuff you lose, it's a really poor idea imo.

[whereagles]

If I were to play this, I would definitely try and profit from the possibility to stop in 2M.

Pass = some diamonds and weakish.
2M = stop, but opener can raise with a super-accept type of hand.
2NT = to play.
3C = usual puppet or muppet stayman.
3D/H = GF transfer. Opener can bid 3NT with a doubleton, so accepting shows a fit and slam ambition. Super-accepting shows a discouraging hand.
3S = whatever you normally play over a 2NT opener.

[antonylee]

Free, on 2011-September-14, 02:22, said:

The only thing you gain by playing 2M/NT natural NF is that you are able to play 2♥ while they have to play 3♥. Compared to all the good and more frequent stuff you lose, it's a really poor idea imo.

Sure, looks convincing to me.

[mike777]

antonylee, on 2011-September-13, 22:12, said:

Hi,
I've recently started looking around Mexican 2♦ (trying to find ideas to rearrange my NT structure should I switch to 11-13-NT, e.g. 11-13=1N, 14-16=1m..1N, 17-19=2♦) (of course I could switch to prepared 1m openings but that's not the point here).
It seems that most response systems use some artificial 2♥&2♠ to ensure right-siding of the contract, but is that really optimal? What about something simpler such as
2M, 2N = to play [or possibly: 2N = some minor(s) oriented scramble / minor(s) strong hand]
3♣ = puppet
3♦♥ = invitational transfer
3♠ = transfer to 3N

True, we wrong-side 2M and 2N but assuming we're in a field where most people play standard, their auction is likely going to be:
- in the 2M case: 1m-1M-2N-P/3M/some sort of signoff; so they've wrong-sided too and they're one level higher;
- in the 2N case: 1m-P ??? and now the opponents are in.
And, much more importantly, we get to play in 2♥, which more artificial schemes do not seem to allow (I believe).

Is the right-siding issue really more important than the ability of signing off in 2♥?

I have played mexican 2d(17/18-19 bal for many years.

You can do a forum search for a more complete response system here in the forums but for starters

95% of the time your auctions will start 2d=2s(forcing 2nt)=2nt(forced) then have a nt auction.


2d=2h=tfr to spades.


if you have any detailed questions feel free to ask.


Again the main reason we play this is to put many 14+ hands into a nt auction and make our lite, wideranging other one level bids more accurate.

1nt=14-16 offshape often
2d=17-19
or 18-19 and 1bid and then 2nt=17.

[antonylee]

mike777, on 2011-September-14, 14:48, said:

1nt=14-16 offshape often
2d=17-19
or 18-19 and 1bid and then 2nt=17.

I thought the 2NT rebid would rather be freed for some other awkward strong hand, e.g. 6m3M? Or some other usefule conventional use?

[mike777]

antonylee, on 2011-September-14, 18:47, said:

I thought the 2NT rebid would rather be freed for some other awkward strong hand, e.g. 6m3M? Or some other usefule conventional use?

IN my example if 17-19 sure...

I mostly play it as 17 and natural and shorten mexican to 18-19 but sure.