CAB is an acronym for Two Clubs, Ace-asking, Blackwood, and is a designation for a bidding system, which enjoyed some popularity in England during the decade of the 1950s. The major contributions to the development of the CAB bidding system is accredited to Mr. Leslie William Dodds, born in the year 1903 and died in the year 1975. Although there were several other contributors to the CAB bidding system one other major contributor was Col. George Gordon Joseph Walshe of London, England, who was born in the year 1873 and died in the year 1959.

Note: One historical feature of the CAB bidding system is that it was developed by Col. George Gordon Joseph Walshe in the early 1930s, and it was Mr. Leslie William Dodds, who actually popularized, promoted, and campaigned for the system. The efforts of Mr. Leslie William Dodds had quite a success when, as a member of the British Team, these players indeed won the Bermuda Bowl in the year 1955 while employing the CAB bidding system. The other team members were Mr. Kenneth Konstram, Mr. Adam Meredith, Mr. Jordanis Pavlides, Mr. Terence Reese, Mr. Boris Schapiro, and Mr. Reginald Corwen (npc).

Note: As our reader Carol Pocock has informed us via email the above description should in no manner suggest or explicitly imply that the CAB bidding system, as devised by Mr. Leslie William Dodds, was also the system employed by all other team members, whose names are mentioned above.

Note: The concept itself is also referred to as the CAB bidding system, the CAB bridge system, the Cab System, and all three designations are correct in the sense that the game was evolving and there was no standard definition of what constituted a bidding system.

Note: Col. George Gordon Joseph Walshe, among other accomplishments, was the the bridge columnist of the London Daily Times writing under the pseudonym of Yarborough. He was also one of the referees at the famous and historical Culbertson-Lenz bridge match, which took place in 1932.

Note: The CAB bidding system was the result of a mixture of popular conventions as the name strongly suggests, and the main promoter of this system was Mr. Leslie William Dodds. During his bridge career he was rather scoffingly designated as the prophet of CAB. The phrase Dodds' Cab was used frequently as in the sense of taking a taxi. At this point in the evolution of the game of bridge there were three bidding systems in contention in the United Kingdom: Acol, Baron, and CAB. Acol won eventually, but it became a heated debate among bridge experts, bridge authorities, and bridge players.

Note: Any additional information as to the CAB bidding system and any information regarding the developers and promoters would be greatly appreciated, as well as any contribution of photographic material.

The CAB system incorporates many elements of the Standard American system and is not completely dissimilar. The bidding system also employed a strong No Trump opening and the partnership agreement was to employ all responses of the concept behind the conventional method of Gladiator.

All opening bids were based on the principle of opening the long suit first, meaning that even if the holding contained a 5-card Major suit the longer Minor suit would be opened first.

Opening Bids

Opening Point Range Card Length
1 12 to 21 high card points Shows a 4+ Club suit.
1 12 to 21 high card points Shows a 4+ Diamond suit.
1 12 to 21 high card points Shows a 4+ Heart suit.
1 12 to 21 high card points Shows a 4+ Spade suit.
1 NT 16 to 18 high card points Shows a balanced holding. Gladiator responses.
2 22 plus high card points Shape may vary. This is a game-forcing opening bid.
2 18 plus high card points Shows a 5+ Diamond suit. Forcing for one round without competition.
2 18 plus high card points Shows a 5+ Heart suit. Forcing for one round without competition.
2 18 plus high card points Shows a 5+ Spade suit. Forcing for one round without competition.
2 NT 21 to 23 high card points Shows a balanced holding.
3   Shows a solid suit.
3   Shows a solid suit.

From the point range, it is obvious that the No Trump opening is strong, and the responses to the No Trump opening are those used in Gladiator, which became popular in New Zealand, however, with variations. As the bidding system was played the requirement for CAB was that the responses to this particular conventional method were mandatory.


Gladiator is a conventional method of responses to a strong No Trump opening bid by partner. The concept was developed by Mr. C. L. Eastgate and Mr. L. M. Killop, both of New Zealand. These responses, modified to a small degree, were basically employed soon after there development in the Roman bidding System and also the CAB bidding system. The perceived and claimed advantage of this response method allowed a more accurate description of the holding of the responder by allowing the responder to indicate strength between a weak zone of 7 high card points, a limit zone of 8-9 high card points, and a strong zone of at least 10 high card points.

A response of 2 Clubs by the responder to an opening of 1 No Trump is a relay bid and the opener is forced to rebid 2 Diamonds. Any minimum suit rebid, for example 2 Hearts or 2 Spades, by the responder then shows weakness, and the opener generally passes.

A response of 2 Diamonds is considered a Stayman-style bid asking the opener if he has a 4-card Major suit, and is generally perceived to be a forcing-to-game bid.

A response of 2 Hearts or 2 Spades is considered absolutely forcing to game, and any and all other responses on the three level are considered forcing to game, but also the exploration of a possible slam. This is where the Blackwood convention is initiated.

After opening a suit, as in the Standard American system, any bid by the responder on the two level shows 10 plus high card points and is a forcing bid. If the responder bids 2 No Trump or jumps in any suit, then the opener is forced to go to game, and possibly slam.

If the responder jumps in the suit of his partner, then the rebid by the opener shows a first round control, such as an Ace or void.

As the name implies, CAB incorporated the Ace Showing Responses method and were usually activated after a strong, artificial Two Clubs opening bid.

1. If the responder bids 2 Diamonds, the responder would be showing zero Aces.
2. If the bid were 2 No Trump, the responder would be showing zero Aces, but 2 Kings and 8 plus high card points.
3. If the bid were 3 No Trump, then the responder would be showing 2 Aces
4. The response of 2 Hearts would show only 1 Ace in Hearts.
5. The response of 2 Spades would show only 1 Ace in Spades.
6. The response of 3 Clubs would show only 1 Ace of Clubs.
7. The response of 3 Diamonds would show only 1 Ace in Diamonds.

Three Level Minor Suit Opening Bids

Any opening on the three level in the Minor suits shows a solid or almost solid suit and no void in the other suits, and is considered to be an invitation to the partner to bid 3 No Trump if he has stoppers in the unbid suits and an entry to the suit of the opener.

Note: The bridge community was eager at that time to experiment with new conventions, systems and bidding methods. The CAB bidding system enjoyed some popularity, but other conventions were devised, which made the auctions more accurate, and in time CAB was used less and less.



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.