This conventional method was designed and developed by Mr. Ely Culbertson in the year 1934 and was published in his book Contract Bridge Complete: The Gold Book of Bidding and Play in the year 1936. Publisher is The John C. Winston Company, Philadelphia, Pennsylvania, ISBN B000KJ31MU, LC:36017463. It is also referred to sometimes as a Captain-Private Four-No Trump Slam Method.

Historical Information

This is perhaps the first bridge conventional method employed in the game of bridge, which asked for the number of Aces, Kings, and even voided suits. Since the scoring method introduced by the leading authorities included bonus points for slams many leading bridge experts, self-proclaimed or not, attempted to find the best method of reaching a slam contract by communicating to partner the number of held honor cards. Mr. Ely Culbertson was perhaps the first of the bridge pioneers to develop and publish such a method.

In a strange but positive twist of fate, as soon as Mr. Ely Culbertson announced and made public his conventional method and before publishing it, the famous Portland Club of London, England, which assumed the role of the promulgator, or the party which announced a Law as a way of putting it into execution, of the Laws of Contract Bridge, at first disallowed this particular bidding method since it presumably could be viewed as a means of playing double dummy, and which, therefore, could / should / must be considered as playing with exposed cards, revealed cards, open cards.

However, in the year 1935, when the new and revised, reworked and updated Laws, titled The Code of Laws of Contract Bridge, were published by the Portland Club it contained the acceptance of The Culbertson Four-Five No Trump convention as being allowed and permissible. It was evident that this particular method, endorsed by the leading bridge personality of the United States, could no longer be refused entry into the annals of the game of bridge. It is rumored, that in order to keep the peace among the governing bodies and also to promote the game of bridge, the organizational and sponsoring bodies should set aside their personal and perhaps political-internal opinions to further the fundamental cause of popularizing the game of bridge.

Mr. Ely Culbertson did indeed enhance, increase, and open the possibility of introducing original, newer, more effective methods and approaches to the game of bridge with this significant victory. It allowed for the members and non-members to present their ideas, their concepts, and their methods to not only be more readily accepted by the governing bodies, but also to be published under the auspices, endorsement and guidance of the corresponding governing authorities promoting the game of bridge.

This conventional method, with a bid of 4 No Trump, could be introduced or initiated by either partner at any time during the auction, preferably after a trump suit has been either established or inferred, and means one of two things shown below. A curious element of this particular method is the fact that the 4 No Trump bidder not only conveys information to partner with the bid of 4 No Trump, but also requests information from partner at the same time.

1.	Promises 3 Aces, which are not specified or identified, or
2.	promises 2 Aces in addition to the King of a real suit bid previously by one of the partners. This bid requests partner, at the same time, to show any Aces.

The first requirement for the application of this Ace-asking method is for the partner, who makes the bid, to be absolutely certain, depending on the suit length(s) and values, that he is able to bid on the five level. This holds also true when a slam is not possible as defined by the continuing auction. If this is not the case, then the Culbertson Four-Five No Trump conventional method should not be employed.

Continuances

1.	If the responder holds zero Aces, then the responder bids the cheapest suit previously bid by one of the partners at the five level. This first response is entirely artificial and reveals no information about the suit itself.
2.	If the responder holds 1 Ace in a suit unbid by the partnership, then the responder bids the Ace in the actual suit at the five level, thereby identifying the suit, in which the Ace is located. If, however, the Ace is held in a higher-ranking suit than the actual trump suit, then this particular Ace is bid only if the holding of the responder holds additional values, which would practically guarantee at least a small slam.
3.	If the responder holds 1 Ace in a suit previously bid by either partner or the Kings of all the suits (real suits) previously bid by the partnership, then the responder bids the suit at the six level, which the responder believes to be the best trump suit.
4.	If the responder holds 2 Aces or 1 Ace and all the Kings of all the suits (real suits) previously bid by the partnership, then the responder bids 5 No Trump.

A particular distinction was defined when introducing this conventional method and must be understood by partnerships employing this method. Mr. Ely Culbertson introduced the idea of real suits, meaning that all such bids are natural; they are not artificial bids. This separation, understanding, distinction is important for the comprehension of this particular method.

For example, the strong, artificial 2 Clubs opening is an artificial bid and names an artificial suit. The Club suit may be the intended suit, but the opening itself is an artificial bid, and therefore not a real suit. As a consequence, the Club suit may not be regarded as a real suit unless bid naturally later in the auction.

A second and important distinction of The Culbertson Four-Five No Trump convention is the fact that if the partnership wishes to sign-off on the five level, then the partner wishing to sign-off may not bid the established or inferred trump suit, but rather the cheapest suit bid naturally or genuinely by the partnership.

As time elapsed and the conventional methods evolved, other enhancements were added in subsequent publications. These features and elements were added as the need arose. Following is a short summary of these enhancements:

1.	If the responder holds 1 Ace in a higher-ranking suit than the established or inferred trump suit (see # 2 above) and does not have the additional values necessary to play in a contract on the six level, then the responder is able to sign-off in the cheapest suit bid by the partnership. This additional feature provided an escape bid for the partnership.
2.	If the responder does not hold an Ace, but rather a voided suit in a lower-ranking suit than the established or inferred trump suit, then the responder should bid the voided suit. If the responder does not hold an Ace, but rather a voided suit in a higher-ranking suit than the established or inferred trump suit, then the responder should not bid the voided suit since this action may cause a duplication of values. This problem was foreseen by Mr. Ely Culbertson and he realized that a void should not be equated to 1 Ace when the partnership could be considering the artificial 5 No Trump response.
3.	If the partner, contemplating a 4 No Trump bid, indeed holds all 4 Aces, then this partner must bid 5 No Trump to show all 4 Aces following the negative response.

An illustration should assist in clarifying this concept as developed by Mr. Ely Culbertson:

Opener		Responder		Meaning
K64 AKJ65 Q8 865		AQJ972 Q104 AK4 A
1				Promises opening values.
		2		Strong jump shift showing at least 6 cards in the bid suit, game values, and a few additional high card points, generally 16 high card points plus.
3				Shows a limit raise and a minimum of 3-card support.
		4 NT		The Culbertson Four-Five No Trump convention, promising either 3 Aces, which are not specified or identified, or 2 Aces in addition to the King of a real suit bid previously by one of the partners. This bid requests partner, at the same time, to show any Aces. (Note: As mentioned, this bid not only conveys information, but requests information.)
5 NT				Promises 1 Ace (unspecified) and the Kings of all suits bid the partnership, namely the King of Hearts and the King of Spades.
		7 NT		The responder now knows that partner holds the Ace and King of Hearts and the King of Spades and, therefore, no losing tricks in these suits. The Club suit can be ruffed. The only uncertainty is the Diamond suit, but since partner has already shown 10 high card points, additional values must be held somewhere and Diamonds is always a likely source.

 

 

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.