WARREN CONVENTION

The origin of this conventional method is unknown. It is also known under the designation of the San Francisco Convention. The conventional method is also known under the designation California Blackwood. It is a variation of the concept known and designated as the Norman convention. This variation allows the partnership to more accurately identify the honors after the trump suit has been established in a slam attempt.

It was used by many bridge players when the game of bridge was evolving and it is also, to some degree, very similar to the concept of the Culbertson Four-Five No Trump convention.

The 4 No Trump bidder, after the trump suit has been established or inferred, is required to hold at least two Aces before being able to make this bid. The responses by the partner show the holding of both Aces and Kings by using only one bid. In order to accomplish this, the Aces are counted as 3 points and the Kings as 1 point, and the responses are as follows:

Responder:
5 :		Shows less than 3 points: no Ace and at most 2 Kings
5 :		Shows 3 points: 1 Ace and no Kings, or 3 Kings
5 :		Shows 4 points: 1 Ace and 1 King, or 4 Kings
5 :		Shows 5 points: 1 Ace and 2 Kings
5 NT:		Shows 5 points: 1 Ace and 3 Kings, or 2 Aces
6 :		Shows 7 points: 2 Aces and 1 King, or 1 Ace and 4 Kings
6 :		Shows 8 points: 2 Aces and 2 Kings
6 :		Shows 9 points: 2 Aces and 3 Kings
6 :		Shows 10 points: 2 Aces and 4 Kings

The responder can also show the number of points for the Aces and Kings even if the opener decides to open the auction with a Strong, Artificial 2 Clubs bid or, by partnership agreement, any Strong Two-Bid in any suit. After this opening the responder uses other bids to communicate to partner the number of points held. This is outlined below using the example of 2 Clubs.

Opener		Responder
2		5		Shows no points
		5		Shows 1 point
		5		Shows 2 points
		5		Shows 3 points
		5 NT		Shows 4 points
		6		Shows 5 points
		6		Shows 6 points
		6		Shows 7 points
		6		Shows 8 points
		6 NT		Shows 9 points, etc.

In the case of Strong Two-Bids, made in any suit, the immediate jump to the Five Level proves to be cumbersome upon the partnership since much bidding space has been eliminated. The possibility and the percentage of ambiguity is increased since the opener must decide as to the number of Aces and Kings held by inference.

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.

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