Contributed by Mr. Bart Moonen - August 2003

Muiderberg is a convention called after the place of birth of one of its inventors. Sometimes Muiderberg is spelled Muiderbergh, but that is in fact incorrect as the Dutch village near Amsterdam is spelled without the letter h.

Muiderberg is a disturbing opening bid of 2 or 2 that promises:

1. a 5-card Heart suit (exactly) or a 5-card Spade suit respectively, plus
2. a 4-card or longer Minor suit, plus
3. 6 - 10 card-points.

It is important that the points are situated in the long suits. Especially the declared Major should have some quality.

This convention fits into bidding systems like Acol or Biedermeijer Red, in which strong hands in Major suits are declared by Artificial Strong 2 and Weak Twos in Major suits are declared by Multicoloured 2 . Muiderberg gives an extra opportunity to declare these special hands, which in fact have a strong distribution. Furthermore Muiderberg disturbs strongly opponents' auction.

Muiderberg is meant to disturb the opponents' auction, but sometimes it disturbs your partner. But there are ways to declare (very) strong hands opposite a Muiderberg opening.

Note 1: Never open Muiderberg if you have a 4-card in the other Major suit. There is to much of a chance you miss a fit in that suit.
Note 2: If your hand is too strong for Muiderberg, then it is strong enough for a normal (Acol) opening bid.

Basic Advances to Muiderberg

Partner has basically the following options:

Not interested in anything else: Pass

Escape to the minor suit of Muiderberg-declarer: 3
Muiderberg opener passes or corrects to 3 . The auction will then stop.
Note that this will always lead to a contract on 3 level. Advancer should ask himself if playing the 2-Major contract even with a 5-2 fit could be the better contract. Escaping is most of the times only better with a void or 1-card in Muiderberg's Major.

Continuing to disturb the opponent further: 3 or 4 /.
There is a fit and especially 4 / could very well be made. In any case Muiderberg passes.

Positive advances (forcing game): 2 No Trump.
With any hand that is forcing game, the advancer starts with 2 No Trump.

After 2 No Trump the Muiderberg-opener gives information about his Minor suit. This can simply be done by 3 / or with more finesse shown in the schema below.

There are several other possibilities, which are given in the next schema.

Complete Schema of Advances to Muiderberg

Note that advancer will never seek a 4-4 fit in the other Major as Muiderberg denies a 4-card in the other Major.

Response Meaning
Pass To play 2 /
2 After 2. Proposal to play. 5-card Spades and Hearts are very short (void or 1 card). Definitely non forcing, since that would be declared with 2 No Trump. Advancer is just seeking a better contract. If Spades does not suit opener (void or 1 card), the opener could introduce his Minor suit (5-card) or bid 2 No Trump to let advancer choose a Minor suit. There is always at least a 4-3 fit. But maybe, with such a misfit, any contract on 2-level is the best.
3 Advancer wants to play in any Minor suit. Opener will pass or correct to 3. The auction then ends. Note that a contract in 2 / with a 5-2 fit could be a good contract. So the advancer will have a void or 1 card in opener’s Major. Note also that both Minor suits must be acceptable (4-card at least).
3 Inviting game in opener's Major. Invitation depends only on the general strength of the opener's hand. With a minimum opener signs off at the 3 level.
3 / (Raising opener's suit).
4 / Advancer want to play this contract. Maybe because he think it will be made; maybe just to disturb the opponent further. In any case the auction ends for the opener. Advancer could raise further for take out.
3 / (Declaring the other Major).
Inviting for game in this Major. At least a 6-card suit and denial of opener's Major suit (void or 1 card).
Therefore the Muiderberg opener could now introduce his Minor suit if it has extra length and if this Major is very short (void or 1-card). But maybe even a 6-1 fit in this Major could be the better contract, if Muiderberg opener has enough quick values.
2 NT Forces game. Fit is not sure yet.
Opener is forced to declare his Minor suit, but there are several options, which are given in the schema below.
3 NT To play. Advancer has no fit in Muiderberg's Major.
Advancer's hand would normally be opened with 2 No Trump. After Jacoby or Niemijer, this would have led to 3 No Trump.

The Auction After 2 / - Pass - 2 No Trump

Opener is forced to give information about his Minor suit(s):

Rebid Meaning
3 / 4-card / or maybe longer, but then the hand is very weak. (Sorry, partner, won't do it again).
3 5-card Club suit.
3 5-card Diamond suit.
3 NT 4-card Club suit plus a 4-card Diamond suit.
4 / 6-card Club or Diamond suit.

Slam?

When the advancer's next bid (after 2 No Trump - ...) is not a game-bid, than he is interested in slam. If Muiderberg is weak, he should stop the auction by raising to game level. Otherwise he should start investigating slam.

There are several options to investigate slam, of which the partnership should choose one.

Opener Bids Splinter (void or 1-card)

Opener Responder Meaning
2 2 NT Game Forcing.
3 Second suit.
3 Forcing.
3 Void or 1-card Spade suit.
4 1-card in Diamonds. Note that a void is, theoretically, not possible, because declarer would then have a 4-card Spade suit, in which case he should not have opened Muiderberg.
3 NT No Splinter; two doubletons in Diamonds and Spades and generally a strong hand (9 or 10 card points).
4 Weak hand.

Bid Controls (Aces, Kings, or Splinter)

Opener Responder Meaning
2 2 NT Game Forcing.
3 Second suit.
3 Forcing.
3 Control in Spades
4 Control in Clubs, but not inSpades.
3 NT No controls, but generally a strong hand (9 or 10 card points)
4 Weak hand.

Further Discussions

There is still more to be discussed:

Opener Responder
2 2 NT
3 / 3
   
or  
2 2 NT
3 3

These must both be strong hands, which normally would have been opened with 2 : semi-forcing in a suit. Because Muiderberg-declarer promises at least 6 card-points, auction should not end below game.

Advancer's Major should be at least a 6-card and there is no fit in Muiderberg's Major. 3 No Trump is still an option. But then the Muiderberg's hand should not be very weak, because of the possibly bad communication between the hands.

Opener Responder
2 2 NT
3 / 3 NT

This must also be a very strong hand, which normally would have been opened with 2 : 23+. Because there is no fit in Muiderberg's Major, this opening bid would have led to 3 No Trump. With a good hand, Muiderberg opener could investigate slam in No Trump.

Opponents Overcall Muiderberg

There does not change very much after an overcall or a double, there are mainly extra possibilities. The most important change is, that 2 No Trump is not forcing to game any more, although it still forces opener to bid his Minor suit.

Auction after 2 / - Double

Redouble We could make this. Advancer wants to double opponent's Major at any level. Muiderberg-opener should double opponent's Minor, if this is his Minor 4-card.
2 NT Asks for Minor suit. Is not forcing any more. Example below:

Opener

Overcaller Responder
2 Double 2 NT Pass
3 Pass 3 Pass
?
3 is now inviting to game, but not forcing.
Cuebid Cuebid is forcing to game in Muiderberg's Major suit. Interest in slam if Muiderberg has a maximum.
Other Rebid Any other rebid is to play.
Question: is advancer's 3 inviting to game or just to play?

Auction after 2 / - 2 /3

Double Punishment / Penalty
2 NT Asks for Minor suit. Is no longer forcing any more. Example below:

Opener

Overcaller Responder
2 2 2 NT Pass
3 Pass 3 Pass
?
3 is now inviting to game, but not forcing.
Cuebid A cuebid is forcing to game in Muiderberg's Major suit. Interest in slam, if Muiderberg is maximal.
Other Rebid Any other suit is to play.

The partnership should discuss this sequence or auction: 2 - 3 - 3 . Is Advancer's 3 inviting to game or just to play?

Auction after 2 / - 3 /

Double Many people play a double in this situation also as punishment / penalty. But there is another dialect/variation: If this suit is by any chance Muiderberg's Minor, then he should pass. Otherwise, he should bid his cheapest suit. Example below:

Opener

Overcaller Responder Advancer
2 / 3 Double Pass
A Pass by the opener shows a 4-card Club suit.
3 rebid by the opener shows a 4-card Diamond suit.

Opener

Overcaller Responder Advancer
2 / 3 Double Pass
3 / rebid by the opener shows a 4-card Club suit.
Cuebid A cuebid is forcing to game in Muiderberg's Major suit. Interest in slam, if Muiderberg is maximal.
Other Rebid Any other suit is to play.

 

 

 

If you wish to include this feature, or any other feature, of the game of bridge in your partnership agreement, then please make certain that the concept is understood by both partners. Be aware whether or not the feature is alertable or not and whether an announcement should or must be made. Check with the governing body and/or the bridge district and/or the bridge unit prior to the game to establish the guidelines applied. Please include the particular feature on your convention card in order that your opponents are also aware of this feature during the bidding process, since this information must be made known to them according to the Laws of Duplicate Contract Bridge. We do not always include the procedure regarding Alerts and/or Announcements, since these regulations are changed and revised during time by the governing body. It is our intention only to present the information as concisely and as accurately as possible.

 


     
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