The origin of this conventional method is unknown. The concept behind this method is to indicate either a two-suited holding or a possible one-suited holding. This opening bid is forcing for one round and the first response allows the opener to clarify his holding.

Concept Parameters

The opening 2 Diamonds bid indicates values ranging from:

1.	Either 7 to 9 high card points and a distribution of 5-5, one suit being a Major suit, or
2.	8-10 high card points with at least a 7-card Minor suit with no Major suit tolerance.
3.	The state of vulnerability may be a determining factor in the length of the two-suited holding: 5-5 or 5-4 in length.

Responses

The responses vary according to the partnership agreement, but the general guidelines include:

2 :	This first response can be employed to show preference to Hearts, but the opener can correct to Spades if the 5-card plus suit is Spades.
3 :	This first jump response shows good Clubs and is an attempt at committing to game.
3 :	This first jump response shows good Diamonds and is an attempt at committing to game.
3 :	This first jump response shows good Hearts and is an attempt at committing to game.
3 :	This first jump response shows good Spades and is an attempt at committing to game.
2 NT:	This first response asks the opener to further clarify his holding. See opener's rebids below:

Opener's Rebids After 2 No Trump

3 :	Promises a 5-card plus suit in Clubs.
3 :	Promises a 5-card plus suit in Diamonds
3 :	Promises a 5-card Heart suit and an unspecified 5-card Minor suit.
3 :	Promises a 5-card Spade suit and an unspecified 5-card Minor suit.
3 NT:	Promises both Hearts and Spades.

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.