The origin of this concept, this particular conventional opening bid remains unknown. A description of this method can be found in the writings and publications of Mr. George D. Jesner, born in the year 1925, of Glasgow, Scotland, but relocated to Canberra, Australia, in the year 1964. Mr. George Jesner died in the month of October in the year 2010. He developed an Acol-based bidding style in the 1950s, which he played actively until his death.

This is a special and specialized opening bid employed in the Acol bidding system, which asks partner directly how many Aces he holds. The bid itself describes a holding with 10 winning tricks, or three or fewer losing tricks. It describes a holding, which is stronger than needed for a minimum strong, artificial 2 Clubs opening bid.

Note: The concept has as a cornerstone the feature that the holding can contain two possible suits as opposed to a strong, artificial 2 Clubs opening bid, which generally shows either a one-suited holding or a balanced holding. Since the strong, artificial 2 Clubs opening bid has evolved to include two-suited holdings, and even three-suited holdings, this distinction does not remain as sharp as at the inception. Therefore, the main distinction remains that the strong, artificial 2 Clubs opening bid may have a minimum requirement of 8.5 winning tricks as opposed to a holding with a minumum of only 10 winning tricks for an Acol 4 No Trump opening bid.

Basic Concept

1.	If the responder holds either zero or 1 winning tricks such as an Ace, then the responder bids according to the following outlined responses below.
2.	If the responder holds at least 2 winning tricks, then the final contract must be a minimum of a small slam.
3.	If the responder holds 3 winning tricks, then the final contract must be a grand slam either in a suit contract or No Trump contract.

The idea behind the entire concept is that if the responder can produce at least two wining tricks, then the responder should assist in establishing the small slam.

The concept behind this opening bid is that the bidding space for any manner of competition by the opposing side has been removed. Since the basic concept is based normally on a solid suit headed by a minimum of two of the top three honors of that suit, then competition is possible by the opposing side in the suit, in which the opener is short. By beginning the auction on the four level, the incentive to compete has been gr

Response Method

The responder bids according to the guidelines outlined below, which inform the opening partner as to the number and even specifying the location of any specific Ace.

5 :	Shows no Ace.
5 :	Shows the Ace of Diamonds.
5 :	Shows the Ace of Hearts.
5 :	Shows the Ace of Spades.
5 NT:	Shows two unspecified Aces.
6 :	Shows the Ace of Clubs.

Examples for Acol 4 No Trump Bids

Example 1
Opener		Responder		Meaning
A KQJ965 4 AKQJ5		8753 104 98 107643
4 NT				Shows a holding containing a minimum of 10 winning tricks.
				Note: the student realizes that the opponents hold 8 Spades, 5 Hearts, 10 Diamonds, and 3 Clubs, and 20 high card points in two combined holdings, which is sufficient for entering the competiion if the opening bid were on the one level. However, entering the auction on the five level is rather risky for any competing partnership.
		5		Shows zero Aces, and informs partner that no winning trick is held.
5				Since the opener knows that partner holds zero winning tricks, then the opener clearly bids 5 Hearts since this is the safest contract. This rebid by the opener establishes the final contract and partner must pass.
				Note: once the opener has been informed of the lack of or the number of Ace(s) held by the responder, then there is no need for any additional continuations, such as King-asking or even Queen-asking.

Example 2
Opener		Responder		Meaning
A KQJ965 4 AKQJ5		8753 A104 Q875 73		Shows a holding containing a minimum of 10 winning tricks.
4 NT				Shows a holding containing a minimum of 10 winning tricks.
		5		Shows only the Ace of Hearts, and denies a second winning card.
6				Since the opener knows that the responder holds only the Ace of Hearts and that the 4 remains a losing trick, then the opener must establish the final contract as a small slam in Hearts, the better, if not longer of the two possible suits.

Example 3
Opener		Responder		Meaning
8 AKQJ10953 AKQ void		A753 104 7543 A54
4 NT				Shows a holding containing a minimum of 10 winning tricks.
		5 NT		Shows two unspecified Aces.
7 NT				Since the opener has only one losing trick, the 8 of Spades and the responder has shown both the Ace of Spades and the Ace of Clubs, then there is no possible losing trick with a solid Heart suit and a solid Diamond suit.

Disadvantage

Although not often included the frequency rate of this particular conventional method is extremely low. Therefore, the employment of a 4 No Trump opening bid lies rather low on the opening bid scale, and is rarely used, if at all.

Convention Card of Mr. George D. Jesner and Mr. John Brockwell of 2002 - 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.