Muiderberg Two Bids

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:

2 - Shows 5 hearts and an unspecified minor.
2 - Shows 5 spades and an unspecified minor.

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

Muiderberg is used in conjunction with the Multi 2 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 3 reply.

Pass Natural.

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

2NT 15+ points, artificial and asking for opener's minor. Please see full description in the next section.

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

3 Artificial, 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.

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

3NT Natural, signoff.

4/ Natural, 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:

3 Natural with minimum strength.

3 Natural with minimum strength.

3 Shows clubs with maximum strength. Forcing.

3 Shows diamonds with maximum strength. Forcing.

Examples

Opener Responder

98 K65

AQT75 K63

K542 86

93 K8654

Opener
2
Pass

Responder
3 (1)

Raise only non-forcing

Opener Responder

9 AK65

KJT75 A632

J54 63

A983 KT7

Opener
2
4 (2)

Responder
3 (1)
Pass

Inviting game in hearts
Accepting the invitation with a maximum

Opener Responder

A9875 KQ

83 AQ52

AJ872 65

6 AQT82

Opener
2
3 (2)
Pass

Responder
2NT (1)
3NT (3)

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

Origins

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

Pass	Natural.
2	In response to a 2 opening bid only. Natural and non-forcing, showing at least a 6-card suit.
2NT	15+ points, artificial and asking for opener's minor. Please see full description in the next section.
3	Shows support for either minor and asks opener to pass or correct. Denies support for opener's major.
3	Artificial, 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.
3/	A single raise shows 3+ card support and is non-forcing. See RONF.
3NT	Natural, signoff.
4/	Natural, signoff. A jump raise may be weak or strong, the same as with a conventional weak two bid.

3	Natural with minimum strength.
3	Natural with minimum strength.
3	Shows clubs with maximum strength. Forcing.
3	Shows diamonds with maximum strength. Forcing.

			Opener			Responder
			98			K65
			AQT75			K63
			K542			86
			93			K8654
			Opener 2 Pass			Responder 3 (1)

			Opener			Responder
			9			AK65
			KJT75			A632
			J54			63
			A983			KT7
			Opener 2 4 (2)			Responder 3 (1) Pass

			Opener			Responder
			A9875			KQ
			83			AQ52
			AJ872			65
			6			AQT82
			Opener 2 3 (2) Pass			Responder 2NT (1) 3NT (3)