This concept was devised by Mr. Eric Crowhurst of England, where the Acol bidding system is the established approach. In the Acol bidding system an opening of 1 No Trump indicates a definite point range from generally 12 to 14 points, as opposed to the point range of 15-17 points normally played in the 5-Card Majors approach such as Standard American.
This concept is designed to assist those bridge players to show this different range agreed upon by partnership agreement. Note: The picture presented below is of Mr. Eric Crowhurst in the year 1992.
The reasoning of Mr. Eric Crowhurst for his concept is that the opening bidder can be dealt certain holdings, whereby a certain advantage could be gained by bidding in a particular manner in order to denote larger ranges in No Trump. This is accomplished by opening a suit following by a rebid of No Trump.
There are six possible auctions, in which the Crowhurst concept can be applied, and they are:
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Opener |
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Responder |
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Opener |
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Responder |
1  |
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1 |
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1 |
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1  |
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1 |
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1  |
| 1 NT |
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1 NT |
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1 NT |
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| Opener |
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Responder |
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Opener |
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Responder |
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1 |
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1 |
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1 |
| 1 NT |
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1 NT |
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| Opener |
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Responder |
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1 |
| 1 NT |
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In all auctions the rebid of 1 No Trump shows a point count range between 12 and 16 points. These six auctions are distinctive and treated differently as opposed to a regular Acol opening of 1 No Trump, which defines the holding as balanced and containing a definite 12-14 point range. In order to discern the difference Mr. Eric Crowhurst developed the Crowhurst conventional method.
The following example should clarify the reasoning behind the concept of Mr. Eric Crowhurst.
| Opener |
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Responder |
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Meaning |
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| 1 |
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1 |
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| 1 NT |
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Showing either a range of 12-14 points or 15-16 points. |
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2 |
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Crowhurst conventional method asking for additional clarification. |
The holding of the opener contains 13 points and falls within the definition and parameters of a regular Acol opening of 1 No Trump. However, the semi-solid Heart suit is overwhelmingly dominant in conjunction with two side suits without stoppers. Therefore, the consensus is to open the holding with 1 Heart as opposed to 1 No Trump.
The rebid of 1 No Trump promises, per partnership agreement, a range between 12 and 16 points. In order to narrow this range Mr. Eric Crowhurst conceived of the 2 Clubs rebid by the responder to inquire. It is the different responses to this 2 Clubs inquiry, which allows the opener to define more narrowly the values of the holding.
Values and Holding Evaluation
The responder has several options once the opener has rebid No Trump. They are as follows:
| 1. |
Pass when holding fewer than game values and the contract cannot be improved. Game values are determined and based on the higher range of 15-16 points. |
| 2. |
Holding game values, also based on the higher range of 15-16 points, the responder initiates Crowhurst. |
| 3. |
When holding possible distributional points, then the responder must make a judgment call regarding continuances. There will always be borderline holdings, which present an individual evaluation. |
Rebids by the Opener
The rebids by the opener allow the responder to determine and establish the final contract. The clarifying rebids of the opener following a Crowhurst inquiry are as follows:
Rebids Showing Support for Responder
These responses are valid in those auctions, in which there is no immediate fit. The following rebids promise support, however the support shows only a minimum of 3 cards.
| Opener |
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Responder |
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Responder |
| 1 /1 |
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1 |
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The response promises a 4-card plus Heart suit. |
| 2 |
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Promises 14-15 points and a 3-card support in Hearts. |
| 3 |
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Promises 16 points and a 3-card support in Hearts. |
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| Opener |
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Responder |
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Responder |
| 1 /1 |
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1 |
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The response promises a 4-card plus Spade suit. |
| 2 |
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Promises 14-15 points and a 3-card support in Hearts. |
| 3 |
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Promises 16 points and a 3-card support in Hearts. |
Impossible Major
In a refinement of this conventional method to overcome a certain disparity Mr. Eric Crowhurst also devised the so-called Impossible Major as the solution to one particular problem not covered by his original conventional method. If the opener indeed has a genuine Spade suit in the following auction, then the opener would bid 1 Spade.
| Auction 1 |
| Opener |
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Responder |
| 1 |
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1 |
| 1 |
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However, in the following auction:
| Auction 2 |
| Opener |
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Responder |
| 1 |
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1 |
| 1 NT |
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2 |
| 2 |
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the opener does not have a genuine 4-card Spade suit to bid. The opener could rebid 2 No Trump to show 15-16 high card points and any distribution. The 2 rebid, an idle bid, by the opener therefore promises a "borderline holding" with a good 14 high card points or a weak 15 high card points indicating that the responder becomes the captain and places the contract. This idle bid of 2 has been designated as the Impossible Major.
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.