mexican two diamonds

The Mexican 2 diamond opening, invented by George Rosenkranz, is an opening bid of 2 diamonds showing a balanced hand of 18 or 19 HCP. Hands with a 5 card major are possible, i.e. any 5332,4432 or 4333 hand is ok for the bid. Whether you decide to include 6 card minors as well is a choice, but I believe those are better opened with one of the minor. The primary advantage of this tool is you don’t have to open with a 1 bid on balanced hands in the range between a 1nt and a 2nt opening. This means when you open 1 of a suit and rebid 2nt over a 1 level response, you can not be balanced. The best way to take advantage of this is via the Mecksroth adjunct.

1 1NT

2 bids - normal but limited to a bad 17 HCP

3x - Promises 55 in spades and bid suit, and a 5 loser hand or less

3 - this is around 15-17 HCP with a good six card suit and a hand unsuited to no trump (i.e. will usually have a singleton or two spade losers).

4 - to play, with at least four key cards missing for slam.

2NT - forcing bid, 17+ HCP, unbalanced. Responder rebids

3 - a hand with a limit raise in spades (10-11 with three spades)

3, - at least a decent five card suit, or any six

4 - a weak spade raise not strong enough for direct raise

3NT - 10-11 HCP balanced, stoppers all suits

3 - anything else, this is an artificial relay asking for more description

1 1NT

2NT 3

3 - 4 card suit, could have 6 spades, responder will usually continue 3 if he has two spades

3 - 4 hearts, may have 6 spades or 4 card minor, but commonly 5422 or 5431

3 - 6 card spade suit, nearly forcing.

4 - to play, but not denying 4 key cards

3NT - typically is 4 cards , 5134,5314 or 5224, could be 6223 with solid club stoppers

1 1NT

2NT ?

3 - limit raise

4 - weak raise

3 - strong diamond suit

3 - strong club suit

3NT - side stoppers with 10-11 HCP

3 - neutral relay

1 1NT

2NT 3

3- 4 card suit

3 - 6 hearts

3NT - 6322 with some help in side suits, or 2524 with good pointed suit cards

3 - confirms 4 clubs, and doubts about no trump

1 1NT

2NT ?

3 - weak, not forcing

3 - natural, club suit or strength, forcing

3M - Stopper, aiming for 3NT, likely weakness in other major

1x 1M

since 3NT can not be balanced and 2nt followed by 3NT can handle all long x hands, 3NT should show a raise of the major. Usually this is used to sort out void and singleton splinters. You can play 1x - 1M - 4 lower as a void, then 3NT is either semi-balanced 4522 or some splinter. With slam interest responder bids 4 to ask for the singleton (1-1-3 is an ordinary splinter, so if needed after 1x - 1NT - 3NT - 4, you can play 4 as a club splinter.

1M 1NT

3x ?

3NT - solid stoppers in unbid suits

3M - may be artificial preference. Can drop bidding if opener rebids 4x.

3 (new suit) - a strong six, since can only hope for doubleton support

3 (new suit) - may be a stopper only

4x (minor) - forcing, with at least the possibility of slam (i.e. 2 possible high cover cards)

5x - no help except in x

jump new suit - splinter in support of x

4M - signoff

Multi auctions with Mexican

2 (multi - Mexican) 2/

2NT (18-19) ?

Treat this exactly like a 2NT opening in terms of responders rebids, i.e. Puppet and transfers on.

2 2NT

3 - max weak two, unspecified major, then 3 asks puppet to major

3 - minimum weak two with hearts

3 - minimum weak two with spades

3 - 18-19 with 5 spades

3NT - 18-19 without 5 spades. 4 then is Puppet for hearts only, opener bids 4 with 4 spades, 4 with 4 hearts, 4 with five hearts, 4NT with no major

If opponents compete over 2, double by opener when responder has not bid shows the 18-19 hand, as do bids of 3 or 3 (presumably with small doubleton in opponents suit). However if responder shows values with a 2NT response and the opponents compete, major bids simply show maximum weak two bids, so you will have to either jump or cue bid to show the Mexican type hand.

Responses to a pure Mexican Two Diamonds (no weak component)

The original responses to the Mexican 2 were based on point count, which isn't particularly useful information. A better response structure aims to show shape, as well as to stop in part scores when appropriate

2 ?

Pass - diamond bust

2 - transfer, showing at least 5 spades, may be weak, super accept with four trumps dead maximum only. Natural game force rebids except 3 is invitational

2 - forces opener to bid 2NT, then responder continues with

3 - Stayman or Puppet Stayman, depending on restrictions for opening bid

3 - transfer to hearts, very weak or game at least. Opener must accept transfer

3/ - a possible use is singleton with 4144 shape (or hearts=club singleton, spades=diamond singleton)

2NT - transfer showing 5+ clubs, opener must accept transfer. Responder is either weak, minor slamish or has a second suit to show. Note this rebid may wrong side the NT, so use with discretion. Can use transfer rebids here also (after 3, responders 3= 4 hearts and 3 = 4 spades

3 - transfer showing 5+ diamonds, natural rebids.

3 - transfer showing 5 hearts invite to game (weaker or stronger hands bid 2 and 3 as above

3/ - singleton in bid suit, 3 of other major, 54 in minors

4 - Gerber

4/ - Texas transfers

This structure is similar to that over a normal 2NT opening, but with the ability to signoff with a very weak hand

AKJ	109xx	2	2NT
xx	x	3	3 (spades)
AKJxx	xxx	4	5
Axx	KQxxx

Kx	9xxxx	2	2
KQ10x	x	2	P
K9xx	xxx
AKQ	108xx

A97	J10xxx	2	2
AJ7	K109xx	2	3
AQ10x	---	3	4
Axx	Qxx