BBO Discussion Forums: Muiderberg Two-Bids - BBO Discussion Forums

I learned from your thread I can defend by calling the director and having the score adjusted for improper disclosure.

The weird thing is that the thread asked what the recommended defence was, yet that hardly received a passing mention.

Basically, you defend as you would against a weak two opening but with a couple of important differences:

1. Double is for take-out, but does not promise support for all three unbid suits. The point is that they have one of the minors, so being 1444 or similar is not only unlikely, but is not even particularly desirable. So you should double 2♠ with:

♠xxx
♥AQxx
♦AKJxx
♣x

I would even do so with the minors reversed. Is it risk free? Clearly not, but it works most of the time.

2. Pass and double is penalties. Example from the database:

[Event ""]
[Site ""]
[Date ""]
[Board "16"]
[West "Jacek Pszczola"]
[North "Andrew Gromov"]
[East "Piotr Gawrys"]
[South "Aleksander Petrunin"]
[Dealer "W"]
[Vulnerable "EW"]
[Deal "W:8.K754.J8642.764 QT642.Q.T53.QJT3 AKJ953.AJ92..AK2 7.T863.AKQ97.985"]
[Scoring ""]
[Declarer "N"]
[Contract "3CX"]
[Result "6"]
[auction "w"]Pass 2S Pass 2NT Pass 3C X AP
[Play "E"]
CA C5 C7 CT
SA S7 S8 S2
S3 H3 C4 S4
CK C8 C6 C3
C2 C9 H4 CJ
S5 D9 DJ D3
HA H6 H5 HQ
[Room "Open"]
[Score "NS -500"]
[BCFlags "1f"]

For those who find the hand unreadable, Gawrys was able to make a delayed "penalty" double on:

♠AKJ953
♥AJ92
♦-
♣AK2

Yes, he would be stuck if they find diamonds, but these people must be punished for bidding with 5-4!

 han, on 2012-June-12, 04:46, said:

pseudo-code for standard practice in applied statistics:


provisory_inference <- some_very_naive_inference

DO UNTIL provisory_inference == desired_inference {
REFINE (provisory_inference)
}

PUBLISH (provisory_inference)

 Cthulhu D, on 2012-June-11, 18:16, said:

How often and by how much do you gain from this? Once your major is known, it is also known that most of your measly HCPs will be in that suit. With the opponents declaring they are going to be finessing partner in the other three suits for any missing high cards. Another downside is wasting the 2♦ which could be used for something else. You can put some discipline into the 2♥ and 2♠ bids by insisting that they are sound when red (9-11 HCP). White you still have OGUST/Feature Ask/Shortage Ask when interested in game?

 32519, on 2013-July-22, 10:21, said:

No. The whole point of the garbage multi is that it is a totally random pre-empt. I've seen xxxxx Kx Kxx xxx and similar type hands opened at favourable. It's intended to be basically just a random destructive opening, and it can be quite effective. Obviously you play a different scheme of responses to the ones you would use opposite a normal weak two.

A question for Muiderbergers:
Is a raise to 3M in the suit opened -
1. Invitational, or
2. Pre-emptive?

 32519, on 2013-August-10, 23:51, said:

Preemptive. Invites bid 3♦.

 Free, on 2013-August-11, 01:01, said:

Then what is the 3♣ bid used for? If you use it as Pass/Correct, then what is the 2NT bid used for?

 32519, on 2013-August-11, 01:17, said:

3♣ is Pass/Correct, 2NT is a (strong) relay to ask for shape and/or strength.

It all makes sense now. You've never encountered anyone playing Muiderberg with 5M-4m because you haven't encountered the opening at all. Otherwise you'd know this.

 Free, on 2013-August-11, 04:17, said:

In two recent tournaments/club games a number of hands came up which met the requirements of Muiderberg. The only pair who used the bid against us failed to alert it. I assumed it was a normal weak two. Only when I saw opener’s full hand afterwards did I realise what had happened. I let it go because the final contract and result wasn’t affected in any way.
For the record, this pair opened a 5/5 hand with 7 HCP.

Back to Muiderberg: As I saw quite a few hands recently which met the requirements, I may just (only maybe) reconsider my opinion of the bid. To do that, tell me your recommended continuation structure after 2NT. You’ve already given me most of the others. Then while you’re at it, what do you use OM (other major) for, whether it be 2M or 3M? 3NT I assume is to play.
2M Continuations:
2NT = Strong relay to ask for shape/strength
3C = P/C
3D = Invitational
3M = Pre-emptive
2/3OM = ?
3NT = To play?

3NT is to play.

2/3OM can be played however you want. I haven't seen anyone play it other than natural, but some prefer to play it NF while others prefer forcing. In the Netherlands and in Belgium there's a tendency not to open a Muiderberg with a 3 card OM, so most prefer a direct bid of OM as NF, trying to improve the contract rather than using it for constructive purposes.

After 2M-2NT you have lots of systems available. Here are a few:
- Prefer to distinguish between min or max:
3m = min, 4+m
3♥/♠ = max, 4+♣/♦
3NT = max, 4-4m (so 5440)

- Prefer to distinguish between 4 or 5 card m:
3m = 4 card m
3♥/♠ = 5 card ♣/♦
3NT = 4-4m (so 5440)

- Interested primarily in 3NT or a distributional minor suit slam:
3m = min, 4m
3♥/♠ = 5+♣/♦
3NT = max, 4m, minor unknown

- Interested in complete relays:
3♣ = any min
3♦/♥ = 4 card m (after which you can relay for exact pattern)
3♠/NT = 5 card m (after which you can relay for exact pattern)

 32519, on 2013-August-11, 05:51, said:

When you say "used the bid against us" does this mean

"Chose to open 2M" or "Had the explicit agreement that they were playing Muiderberg"

If the latter holds true, how do you know that the pair in question was playing Muiderberg rather than chose to open an offshape 2M playing standard methods?

As has been pointed out many times, 5/5 is not what is classically referred to as Muiderberg.
There are many different 5/5 openings - CRO, OCR and CRO are but 3 Multis.
Then you have 2H = H+?, 2S = S+m, which are often part of Polish systems.

I guess you have never played against Muiderberg?

Is there any way of combining natural weak 2s with Muiderberg hand patterns? The continuation bidding will need to sort out which hand type opener has. Sure you may end up playing in a 6-1 major suit on level 3. However that may not necessarily turn out to be a complete disaster when responder was showing preference for the minor suits. Hopefully some of openers minor suit losers can be taken care of in responders hand.

 32519, on 2013-August-11, 23:53, said:

The usual way to do this is just to accept playing in 2M when responder is weak. The bad hand where you actually want to run into responder's minor suit a level higher is kind of rare -- if you have doubleton in opener's major you usually want to play in 2M. So this leaves stiff in opener's major, but you also need 4-4 in the minors (a 4-3 fit at the three-level is dangerous and it's often better to play a 5-1 at the two-level at least until they double). The point being, this 1444/1435/1453 hand hardly comes up, so you're probably okay playing 2M = 5M+4m or 6M and just passing with a weak hand. You do want a way to sort things out if responder is looking for game or slam, but then you have a reasonable amount of space available (something like 2♠-2NT and 3♣=min with a minor with 3♦ asking which, 3♦=max with a minor and 3♥ asking which, 3♥=min one suited, 3♠=max one-suited would seem to work).

 32519, on 2013-August-11, 23:53, said:

As usual, Chris Ryall's site is the first point of call for any questions of this type. The "Alexander" method linked to is a version of what you are looking for. Remove the (anyway dubious) side requirements and it is exactly.

Note also that this is exactly the same page as the one I linked to for Muiderberg. Notice also that within the Muiderberg entry is an alternative 2♠ response scheme using a Lebensohl-based method. There are other alternatives around too, such as using 3♣ as an invitational advance. Finally, the response scheme I personally use is as per Free's method 1 (min/max), except that over 2♠ I prefer 3♥ to be the good raise and 3♦ to show hearts.