Source: Bridgeguys
The origin of this conventional method is unknown. The concept is to determine the location of specific Aces and Kings with an opening bid of 3 No Trump. The opening bid is forcing and implies a very strong holding with three or fewer Losing Tricks. After determining whether partner holds any specific values and the location thereof, the opener is then able to set the correct contract at the correct level.
Note: The first response show only the location of one Ace. These first responses do not allow the responder to show two or three Aces. Since the Kabel 3 No Trump opening bid shows a holding with three or fewer losing tricks, then it is quite doubtful that the responder could hold more than one Ace or one King. Therefore the necessity of showing two or three Aces is not present.
Responses
Opener Responder Meaning 3 NT An opening bid of 3 No Trump asks the responder for the location of held Aces. 4 Shows zero Aces. 4 Shows the Ace of Diamonds. 4 Shows the Ace of Hearts. 4 Shows the Ace of Spades. 4 NT Asks the responder for the location of held Kings. 5 Shows zero Kings. 5 Shows the King of Diamonds. 5 Shows the King of Hearts. 5 Shows the King of Spades. 6 Shows the King of Clubs. Continuations following a 5
first response to a 3 NT opening, which promises the Ace of Clubs are as follows:
Opener Responder Meaning 3 NT Asks for the location of held Aces. 5 Shows the Ace of Clubs. 5 NT Asks for the location of held Kings. 6 Shows the King of Diamonds. 6 Shows the King of Hearts. 6 Shows the King of Spades. 7 Shows the King of Clubs.
Note that the first responses do include the possibility of discovering the location of the held Kings as opposed to the variation presented below, which only addresses the location and number of held Aces.
Example
The following example should assist in clarifying the employment of this three level opening bid. Since the opener has a holding with three or fewer losing tricks the concept only allows the responder to bid only what is requested.
North 104 94 AK9865 643
West 8765 52 73 AKJ72
East 92 1086 J102 Q10985
South AKQJ3 AKQJ73 Q4 Auction
North East South West Pass Pass 3 NT Pass 4 Pass 4 NT Pass 5 Pass 7 All Pass
Once North discovers that partner holds both the 
Ace and King, then North bids the grand slam, knowing that there are no losing tricks in Diamonds. The only danger to the fulfillment of the contract would be a 5-0 split in trump topped by the Ten.
Variation of the Original Version
This variation does not provide the opportunity to ask for the location of any held Kings.
Opener Responder Meaning 3 NT An opening bid of 3 No Trump asks the responder for the location of held Aces. 4 Shows zero Aces. 4 Shows the Ace of Diamonds. 4 Shows the Ace of Hearts. 4 Shows the Ace of Spades. 5 Shows the Ace of Clubs. 4 NT Shows two non-touching Aces. 5 Shows the Ace of Diamonds and the Ace of Hearts, the next higher-ranking suit. 5 Shows the Ace of Hearts and the Ace of Spades, the next higher-ranking suit. 5 Shows the Ace of Spades and the Ace of Clubs, the next higher-ranking suit. 6 Shows the Ace of Clubs and the Ace of Diamonds, the next higher-ranking suit. 5 NT Shows three Aces. The origin of this response variation following the Kabel 3 No Trump opening bid is unknown. Source is Mr. Lorne Russell of the website for Bridge Squeezes Complete.