This conventional defense method was devised and developed by Mr. R. James Donaldson of Vancouver, Canada. The Jim Donaldson Trophy is awarded to the winners of the Canadian Open Pairs Championship, the first of which was conducted in 1985.
The features behind the concept of this variation are employed after a No Trump opening by an opponent. Whether or not the concept can / should be employed only in the immediate seat or also as a balancing action is dependent on the partnership agreement.
The competing partnership may have to alter the held values depending on the range of the No Trump. The reasoning behind the concept, as with practically all the conceived defense methods, is that the partnership interfere with the bidding of the opponents and to hopefully discover an immediate fit.
The bids and the meaning thereof are shown below.
Double: It is the obligation of the partnership to determine whether or not the double is penalty-oriented or not. The decision is based on several factors such as whether a double shows also a No Trump opening and/or a long running suit. 2 : Promises one of the two Major suits, either Hearts or Spades.1. The advancer bids 2 if Hearts is the preferred suits and 2 if Spades is the preferred suit. The reason for not bidding the preferred suit directly is that the lead is intended to come through the No Trump bidder. 2 : Promises a three-suited holding.The advancer bids the longest suit in the holding. If this suit is not one of the three suits, then the intervenor corrects to the next higher-ranking suit. With equal length in two suits, or by a distribution of 3-3-3-4, then the advancer bids the next higher-ranking suit Hearts. 2 : Promises Hearts and an unspecified Minor suit.If the advancer wishes to discover the Minor suit, then the advancer will bid 2 No Trump and the intervenor then names the Minor suit. 2 : Promises Spades and an unspecified Minor suit.If the advancer wishes to discover the Minor suit, then the advancer will bid 2 No Trump and the intervenor then names the Minor suit. 2 NT: Per partnership agreement. 3 +: All bids on the three level are natural and preemptive.
The overcalls employed in the Donaldson defense conventional method, which show a two-suited holding, normally show two suits with a minimum of five cards in each suit. This requirement may be more flexible depending on the state of vulnerability and reduced per partnership agreement to a 5-4 shape.
Whether or not the partnership can employ the Donaldson Over No Trump defense method with a 4-4 distribution was not addressed in the original version and, therefore, is purely a matter of partnership agreement.
The number of high card points or other evaluation methods are not addressed in the original version, but the standard values should be maintained expecially when employing the Losing Trick Count method. Both the values and the result of the evaluation method should fall within agreed upon parameters before deciding to compete.
Whether or not the Donaldson defense conventional method can be employed after a 2 No Trump opening is a matter of partnership agreement.
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.