A cooperative double is a double that provides the partner the option, information for deciding to, or the opportunity of passing for penalties or to continue bidding. This is the essence, the intrinsic quality, and the characteristic feature of the cooperative double.

Note: Cooperative doubles are employed mostly on low-level bidding auctions. They generally do not reach or exceed the three level.

Note: Although not specifically and/or officially recommended the employment of the cooperative double remains a partnership agreement based mainly on the values of the combined holdings, whether it is based solely on high card points, or high card points together with distributional points, or based on the inferred number of combined losing tricks. The call itself is also based on the fact that neither side, in a competitive auction, has game values combined based on any and every evaluation method.

Note: The designation cooperative double was originally employed by Mr. Ely Culbertson in the 1930s to describe a double of an opening three-level bid of any suit. Source: OEofB 1971. Thus the assumption is made that the designation is a remnant of the era of Whist and Bridge Whist, a card game which reached its peak of popularity in the late 19th century and early 20th century, and which continues to be played competitively today.

Most bridge players do not employ the cooperative double, but this fact does not in any way signify that this form of the double has become obsolete, or is not worth exploring.

Takeout Double vs. Cooperative Double

The first and second examples serve to illustrate the difference between a takeout double and the initiation of a cooperative double.

Example 1:
West		North		East		South		Meaning
Pass		Pass		1		Double		1. Takeout Double by South.
								2. Support in all other unbid suits.
								3. Strongly suggests a 4-card Spade suit.
Example 2:
West		North		East		South		Meaning
1		2		Pass		Pass
2		Pass		Pass		Double		1. Cooperative Double by South.
								2. Final decision is the option of North.

Reviewing the second auction, it is apparent that South has moderate to very good defensive strength, shortness in Hearts, and medium support in Diamonds. The cooperative double by South puts East-West into a game contract, but South is informing his partner that they may have a contract and also that they may be able to defeat the contract of their opponents. South finds himself in a position that he cannot, with his holding, guarantee a penalty, and therefore, South is clearly leaving the final decision up to his partner.

Example 3:
South		West		North		East		Meaning
1		Pass		Pass		Double		Takeout / Balancing Double by East.
1		2		Pass		Pass
Double		Pass		Pass		?		Cooperative Double by South.

After two passes, East decides to make a takeout double. South rebids 1 Spade, showing generally somewhere around 18-19 high card points. His distribution and strength do not allow him to open No Trump. West decides to enter the auction with a bid of 2 Diamonds, which is passed to South, who doubles. Hence South only has the Cooperative Double left as his only option, leaving the decision up to his North whether to pass for penalty or to bid.

Note: The bridge student will notice that the call of double can change its meaning in a single competitive auction.

Optional Double or Cooperative Double

During the evolution of the game of bridge certain definitions of designations were changed, altered, and modified. The parameters were re-defined, re-adjusted, and fine-tuned. The optional double is closely related to the cooperative double. Originally the optional double was defined as the employment of a double following an opening preemptive bid by an opponent almost always on the three level. This definition has not changed significantly.

South		West		North		East		Meaning
Pass		3						Preemptive opening showing weak values.
				Double				Defintion: optional double.
				AK76 A KJ109 QJ75

The partner of the doubler, namely North, had the option of converting to a penalty double, or bid and convert to a takeout double.

The principle difference is that the cooperative double does not include this option in combatting a preemptive opening bid on the three level. Although both definitions may seem similar, the application and employment are sufficiently distinct to deserve a singular defintion.

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.