In bridge, Muiderberg Two Bids are weak opening preempts. They show 5-10 points, a 5-card major and at least a 4+ card minor:

  • 2H - Shows 5 hearts and an unspecified minor.

  • 2S - Shows 5 spades and an unspecified minor.

At unfavorable vulnerability, the minor should be 5+ cards.

Muiderberg is used in conjunction with the Multi 2D convention that shows a weak 6-card major. The idea is to simply add more preempts to one's arsenal.

The convention is also known as Lucas Two Bids (albeit with slight differences) or Dutch Two Bids.


Responses

Partner's responses are all non-forcing with the exception of an artificial 2NT or 3D reply.

PassNatural.

2SIn response to a 2H opening bid only. Natural and non-forcing, showing at least a 6-card suit.

2NT15+ points, artificial and asking for opener's minor. Please see full description in the next section.

3CShows support for either minor and asks opener to pass or correct. Denies support for opener's major.

3DArtificial, showing 3+ card support with game-invitational strength. Opener is expected to sign off at 3-level with a weak hand, or bid game with a maximum.

3H/SA single raise shows 3+ card support and is non-forcing. See RONF.

3NTNatural, signoff.

4H/SNatural, signoff. A jump raise may be weak or strong, the same as with a conventional weak two bid.


Opener's Rebids After 2NT

Responder's 2NT is strong and artificial, representing a variety of possible hands. It asks opener to show his minor suit.

Responder may be genuinely interested in identifying the correct minor suit strain. Or he may have game or slam aspirations in the major suit, and simply wants to know more about opener's hand.

After hearing 2NT, opener may bid as follows:

3CNatural with minimum strength.

3DNatural with minimum strength.

3HShows clubs with maximum strength. Forcing.

3SShows diamonds with maximum strength. Forcing.


Examples

OpenerResponder
98SK65
HAQT75K63
DK54286
C93K8654

Opener    
2
Pass

Responder    
3 (1)

  1. Raise only non-forcing


OpenerResponder
9SAK65
HKJT75A632
DJ5463
CA983KT7

Opener    
2
4 (2)

Responder    
3 (1)
Pass

  1. Inviting game in hearts
  2. Accepting the invitation with a maximum


OpenerResponder
A9875SKQ
H83AQ52
DAJ87265
C6AQT82

Opener    
2
3 (2)
Pass

Responder    
2NT (1)
3NT (3)

  1. Asking for opener's minor (and hoping for clubs)
  2. Showing diamonds with maximum strength
  3. Signing off after hearing the misfit


Origins

Muiderberg was named by its Dutch inventors Onno Janssens and Willem Boegem for their homedown of Muiderberg.

See also

  • Multi 2
    An artificial 2 opening bid showing either a major suit preempt or a strong 4441 hand.

  • Raise Only Non Forcing
    The practice of raising a weak two bid as a preemptive, non-forcing bid.

  • Weak Two Bids
    Opening bids of 2// to show a 6-card suit with a weak hand.

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