Translation of: Defense Against Muiderberger Two- By: Christine Karman

The predominant objective of the Muiderberg convention is to keep opponents out of the bidding or to confuse the opponents so that they are obstructed in their bidding process. Since the Muiderberg conventional method is becoming increasingly popular, especially in the Netherlands, it is important to have an effective defense mechanism.

Basic Concept

This defense mechanism against the Muiderberg convention is based on the principle of "Keep It Simple". The same principles are used as against an ordinary opening. The fundamental principle to know is that the Muiderberg convention takes the bidding auction one level higher, and therefore the overcalls and doubles need to have more substance.


After a Muiderberg conventional opening, every double is informative when the partner has not bid, but has passed. There are two requirements:

1. The double promises a hand with opening values, 13 points or more. In the balancing position, the player can double with less than 13 points. In this situation the player may, however, have no more than eight losers.
2. The double will promise a hand that is short in the opening suit with preferably four cards in the other Major suit.

The responses to the double are natural. However, the player can use the conventional method, which is becoming increasingly popular, and is called the Negative 2 No Trump. The responses and their meanings are shown below after the bidding sequence of:

Auction   2   Double   Pass
Pass: Pass for Penalty.
2 NT: Weak hand, maximum of 10 points, minimum of 8 losers. Requires partner (second position) with normal informative double to bid 3. After that, you pass or bid your own suit. If the partner (second hand) is much stronger (for example: 6 losers or less), then they bid his/her own suit instead of 3.
3 : Partner's suit, inviting. (Good 5+ card and maximum 8 losers)
3 : Partner's suit, inviting. (Good 5+ card and maximum 8 losers)
3 : Partner's suit, inviting. (Good 5+ card and maximum 8 losers)
3 NT: To play.
4 : Your suit, forcing.
4 : Your suit, forcing.
4 : To play.

Overcall of 2 No Trump

In the second position with 2 No Trump, you are promising 15-18 points. In the fourth position you have 14-17 points. This does not deny a 5-card Major suit, so after the 2 No Trump overcall you can play Neimeijer or Puppet Stayman.

Overcall in a Suit

This is only done when you have a strong hand and you definitely want to bid. That is, if by not bidding, you risk that your partner also passes and you miss a possible game.

A jump overcall is promising a strong hand with a minimum of a 6-card suit and a maximum of 6 losers. There is no use for a weak jump against the Muiderberg convention. Do not employ a preemptive bid against a preemptive bid.


Some pairs play transfers after the double of the partner. The risk they take is that by doubling, the opponents regain the initiative in the bidding process. Against a preemptive bid, you need to find and bid a fit as quickly as possible.



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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