Ekren convention

Responses to a 2♦ Ekren opening:[1]

Pass = to play (can be a tactical manoeuvre in the absence of a major suit fit and does not guarantee long diamonds)

2♥/♠ = to play

2NT = relay (invitational or stronger)

3♣ = natural, not forcing

3♦ = invitational with 3-3 in the majors

3♥/♠ = preemptive, to play

4♥/♠ = to play

In responding to the 2NT relay the opener indicates whether he holds a minimum or a maximum (because of their playing strength 5-5's are generally considered maximum), and - in case of a maximum - the distribution in the majors:

3♣ = any minimum (responder's 3♥/♠ rebid now indicates an invite)

3♦ = 5-5 min or max (creates game force)

3♥ = 4-5 max (creates game force)

3♠ = 5-4 max (creates game force)

3NT = 4-4 max (creates game force)

Variants of Ekren include the use of the 2♥ opening to indicate a weak hand with at least a 4-4 in the majors.[2] This treatment has the advantage that the left hand opponent of the opener can hardly gamble on the fact that (s)he will get a second chance to bid.

Another variant that is popular in the Netherlands (where it is referred to as Tilburg Two) and Belgium is to accommodate the Ekren hands as a weak variant in the strong 2♣ opening. This leaves untouched the 2♦/♥/♠ openings which are commonly utilised in the Low countries as Multi 2 diamonds and Muiderberg (also known as Tartan or 'Jón og Símon') openings. Also, a 2♦ relay is now available to responder that can be used to ask for the longest (or better) of the two major suits.