This conventional defense method was originated by Mr. John Trelde and Mr. Gert Lenk, both of Copenhagen, Denmark. The concept is a system of jump overcalls, which promises a two-suited holding after the auction has been opened by an opponent in a suit on the one level.

Note: This conventional defense method is also known as Danish Asking Bids.

Note: The Trelde Asking Bids were first published in the magazine Dansk Bridge in August 1972. and in four following issues.

The values should correspond to the level of the indicated and the working values should be located mainly in the indicated two suits. The decision to overcall may also be based on the number of Losing Tricks, which is the preferred method of evaluation. The originators stated that the pattern should be at least a 5-5 distribution and the holding must contain at most 5 Losing Tricks if the state of vulnerability is unfavorable. By favorable vulnerability the number of Losing Tricks should total 6 Losing Tricks and, at the most, 7 Losing Tricks. By equal vulnerability, both vulnerable or both non-vulnerable, then the maximum number of Losing Tricks should be 6 Losing Tricks.

The following schematic describes and explains the overcalls:

2 NT:	Promises at least a 5-5 distribution in the lowest-ranking two unbid suits.
3 :	Promises at least a 5-5 distribution in the top and bottom unbid suits.
3 :	Promises at least a 5-5 distribution in the highest-ranking two unbid suits.

Example 1, whereby both sides are vulnerable:

East		South		Meaning
106 Q74 AK9 KJ1064		AK974 KJ985 6 A3
1		3		Copenhagen conventional method showing at least a 5-5 distribution in the highest-ranking two unbid suits.

The continuances are mainly based mainly on an agreement established by the partnership.

Bidding Conditions

The Copenhagen conventional method may also be employed according to the above described overcalls in the fourth seat following two passes. However, if both opponents are competing, then only the bid of 2 No Trump is employed to show a two-suited holding in both of the unbid suits.

Example 2, whereby both sides are vulnerable:

East		South		West		North		Meaning
106 Q74 AK9 KJ1064		J83 A106 J732 875		Q52 32 Q10854 Q92		AK974 KJ985 6 A3
1		Pass		1		2 NT		Copenhagen conventional method showing a two-suited holding in both of the unbid suits.

In a competitive bidding sequence, as shown above, if the opening bidder bids again, then the advancer is not required to bid.

Continuations

In bidding sequences, whereby the advancer has the opportunity to compete, then the advancer should give preference to one of both specified suits of the intervenor, which could result in the advancer becoming the declarer.

In rare instances when the advancer holds values worthy of slam attempts, then the advancer will cuebid the suit of the opener first before establishing a trump suit. The cuebid is an asking bid and the intervenor is required to bid in steps to show the number of Losing Tricks in the holding. The bridge student should be aware of the fact that the main features of the Copenhagen conventional method are based on the Losing Trick Count method.

The intervenor, following a cuebid by the advancer replies according to the following guidelines:

Bid		Vulnerable		Non-Vulnerable		(Optional): Equal Vulnerability
First Step:		Shows 5 Losing Tricks		Shows 6/7 Losing Tricks		Shows 6 Losing Tricks
Second Step:		Shows 4 Losing Tricks		Shows 5 Losing Tricks		Shows a maximum of 5 Losing Tricks
Third Step:		Shows 3 Losing Tricks		Shows 4 Losing Tricks		Shows a maximum of 4 Losing Tricks

Example 3, whereby both sides are vulnerable:

East		South		West		North		Meaning
Q4 KQJ85 KJ10643		AK974 KJ985 6 A2		632 73 1097432 85		QJ1085 A1062 A Q97
1								Conventional opening bid with sufficient values.
		3						Copenhagen conventional method promising at least a 5-5 distribution in the highest-ranking two unbid suits.
				Pass		4		The advancer cuebids the suit of the opener to discover if there is a slam possibility. The cuebid also assures partner that there is an implied fit in either one or both Major suits, which means that there are perhaps two fits of minimum 5-3 distribution in both suits.
Pass		4		Pass				By bidding the First Step the intervenor shows 5 Losing Tricks according to the state of being vulnerable.
						4 NT		The advancer, knowing that the actual Losing Trick count almost guarantees slam, double-checks by bidding Blackwood. The correct contract of 6 Spades will be reached.

Important Note of Clarification

The originators, both Mr. John Trelde and Mr. Gert Lenk, realized that a certain flaw was inherent in their method and that is the fact that the method pushed the intervenor immediately to the three level. Therefore, they both placed emphasis on the fact that the partnership must be acutely aware of the state of vulnerability and also the number of Losing Tricks promised in connection also with the number of working points.

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.