The origin of this variation of the Blackwood conventional method is unknown. Once a convention has been adopted by the majority of players in the bridge community, there are inevitably variations and modifications. The concept of asking for Aces and Kings is one of those conventions where many modifications abound.
From the Blackwood Convention, there is the variation of Roman Key Card Blackwood, which is an Ace-asking bid and where the King of Trump is counted as the fifth Ace or Key Card, and Key Card Blackwood.
Note: It must be stated, and the bridge student reminded, that this variation does not include the possibility of showing the possession of the Queen of the established or implied trump suit.
Key Card Blackwood is a variation of the Blackwood convention, whereby the four Aces and the King of the trump suit are counted as Key Cards. Based on the following example, and other similar examples, where the trump suit has been predetermined, the different responses listed below show the number of Key Cards held.
The bidding auction is only one of many possible bidding sequences, whereby the trump suit has been either been directly established or implied.
Opener Responder Meaning 1 3 Limit raise by responder. 4 NT Keycard Blackwood
5 : Shows 0 or 4 Key Cards 5 : Shows 1 or 5 Key Cards 5 : Shows 2 Key Cards 5 : Shows 3 Key Cards
After having established that all Key Cards are held by the partnership, a bid of 5 No Trump can be made to determine the number of Kings held, counting the three remaining Kings left.
6 : Shows 1 King 6 : Shows 2 Kings 6 : Shows 3 Kings
Although this Key Card Blackwood convention entertained some popularity at one time, it has generally been replaced by the Roman Key Card Blackwood convention.
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.