Muiderberg convention

From Wikipedia, the free encyclopedia
  (Redirected from Muiderberg (bridge))
Jump to navigation Jump to search

Muiderberg is a bidding convention in the card game bridge. It is a two-level preemptive opening based on a two-suiter with precisely a five-card major and a minor suit (four-card or longer). In Muiderberg the 2 opening denotes five hearts and an unknown minor suit, whilst 2 denotes five spades and an unknown minor suit. The convention is also known as the Dutch Two, Lucas Two or Woo Two (mainly UK) opening.[1]

The convention is named after the Dutch village Muiderberg, the residence of the designers of the convention - Onno Janssens and Willem Boegem.[2]


The partner of the Muiderberg opener can take the following actions:

  • pass (with tolerance for the opened suit)
  • bid 3 (a pass-or-correct bid)
  • bid 3 to invite for game in the major suit
  • bid 2 (over 2) as a contract improvement (opener is allowed to raise with a suitable hand)
  • bid 3/ (opener's suit) as a preemptive raise
  • bid 3/ (other major) which is non-forcing but invitational
  • ask for the minor suit using a 2NT relay bid with a strong hand.

The 2NT response is often defined as forcing to game, for example in Biedermeijer and AcolPlus. In particular, with a strong hand with an own suit, responder must bid 2NT first as there is no other way to establish a force. The Muiderberg opener can respond in several ways to the 2NT answer:

  • bid 3 with a minimum and clubs / with a four clubs
  • bid 3 with a minimum and diamonds / with a four diamonds
  • bid 3 with a maximum and clubs / with a five or more clubs
  • bid 3 with a maximum and diamonds / with a five or more diamonds
  • bid 3NT with 4-4 in both minors
  • bid 4/ with a 6+ cards in the bid suit

Both approaches are equally popular.

In competition, 3 is natural (opener is expected to pass) while 2NT asks for opener's minor suit and is not necessarily strong. Further, 4/ are defined as fit-bids in competition.


A variant known as Lucas Twos allow for five cards or more in the bid suit (diamonds, hearts or spades) and four cards or more in a second suit which can be any of the remaining three suits.

Another variant, called Antispades Twos, provides for either a two-suited hand containing at least nine cards in the two suits with four or more cards in the bid suit — clubs, diamonds or hearts — and four or more in another suit, or a single-suited hand of at least six cards in the bid suit, in a hand worth 5-10 HCP.

See also[edit]


  1. ^ "Muiderberg". Bridge Guys. Retrieved 7 November 2015.
  2. ^ Manley, Brent, Editor; Horton, Mark, Co-Editor; Greenberg-Yarbro, Tracey, Co-Editor; Rigal, Barry, Co-Editor (2011). The Official Encyclopedia of Bridge (7th ed.). Horn Lake, MS: American Contract Bridge League. p. 282. ISBN 978-0-939460-99-1.CS1 maint: Extra text: authors list (link)