This conventional method was devised by Mr. David F. Buchanan, and was published in Bridge Magazine in January, 1980. This publication is promoted as the longest continuous running Bridge magazine in the world, founded in the year 1926. In various references the designation is shortened to Buchanan, or Buchanan Defense to 1 No Trump.

Note: Any additional information as to the person of Mr. David F. Buchanan, especially photographic material, would be greatly appreciated.

The CDH Buchanan defense method is employed mainly against weak No Trump openings by the opponents. The conventional method requires that the overcall be based on a two-suited holding of 4-4 distributional pattern or greater. The held values should amount to about 10 to 14 high card points.

The CDH designation is short for Clubs-Diamonds-Hearts Buchanan. The following schematic explains the overcalls and their significance of this defense method. The defense method is also, more simply, referred to as Buchanan. Other source: Buchanan, which has only been preserved and archived on this site in .pdf file format for future reference.

CDH Buchanan Defense Bids

The following outline presents the original version up to and including the bid of 2 No Trump. Any higher bid suit above 2 No Trump becomes preemptive in nature. The comparison of this conventional defense method has been made to the D.O.N.T. conventional defense method as published by Mr. Larry Cohen in his book To Bid or Not To Bid, page 90, but there are several differences upon detailed comparison.

Double:	Any double is for penalty. Partner must pass. Point range is per partnership agreement, which is generally 15 plus points.
2 :	Shows Clubs plus an unspecified higher-ranking suit: Diamonds or Hearts or Spades.
2 :	Shows Diamonds and an unspecified higher-ranking suit: Hearts or Spades.
2 :	Shows both Major suits.
2 :	Shows a one-suited holding with Spades.
2 NT:	* This bid can be employed to show a single-suited holding in a suit other than Spades. However, in other presentations 2 NT is an idle bid and can be employed as wished by the partnership, possibly to show both Minor suits.
3 :	Preempt in Clubs. Promises a minimum of a 6-card plus suit.
3 :	Preempt in Diamonds. Promises a minimum of a 6-card plus suit.
3 :	Preempt in Hearts. Promises a minimum of a 6-card plus suit.

The shape and distribution of the holding determines primarily the decision to make an overcall or not. The high card point count is secondary although the location of the values is a strong determining factor. The distribution is generally 5-4 by favorable vulnerability and should be 5-5 by unfavorable vulnerability when two suits are shown. Whether or not the principle concept can be employed with a distribution of 4-4 by any vulnerability is a matter of partnership agreement as are the responses.

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.