Roman Key Card Blackwood
This is a refinement of Blackwood that asks about the king of trumps in addition to the four aces - the five making up the so-called key cards - and sometimes provides extra information about the queen of trumps. Usually knowledge of these five or six cards is sufficient to determine whether or not slam is on.
When to use RKCB
If the loser count, or loser plus covers, suggests slam is on, then check for key cards. If one key is missing, small slam is indicated; if none, grand is possible.
You must ONLY use RKCB after a trump suit has been agreed. However, a partnership may agree that a jump to Blackwood implicitly accepts partner's last natural bid suit. Use your judgment if it's not clear; such a jump without clear agreement might also be indicative of a standard Blackwood ask for aces with the intention of playing in no-trumps.
How to bid
The asking bid is 4NT. The responses are:
| Response | Number of key cards held | Queen of trumps |
|---|---|---|
| 5C | 0 or 3 | no information |
| 5D | 1 or 4 | no information |
| 5H | 2 or 5 | held |
| 5S | 2 or 5 | not held |
Asking for kings
King asking is not usually needed given the extra information provided by RKCB over standard ace-asking. Because of this, there are many ways to do so; beware!
A simple count (a la ordinary Blackwood or Gerber) could be asked with 5NT, but it runs the risk of pushing you higher up the bidding than is comfortable.
Alternative technique
This one is suggested by Ron Klinger.
Initiator bids the next non-trump suit. This promises that the partnership holds all five keys, and enquires about the queen of trumps and outside kings.
Responses:
- 5 of trumps shows no outside king, nor QT
- 6 of trumps shows no outside king, have QT
- anything else is a cue bid showing the QT and at least that king - always the cheapest one possible.
Over a cue bid, the initiator probably wants to bid 6 of trumps; responder should then bid up to 7 if they have a further outside king, or indeed if they have some other good as-yet undisclosed source of tricks.
Resolving ambiguety
A similar technique to king-asking can be used when it's not clear to the initiator which of the two meanings of the response applies.
For example, consider a 5C response when initiator holds two key cards; responder has zero or three keys. In this case, the initiator should sign off in 5 of trumps (which obviously doesn't work if clubs are trumps; that's life); the responder should pass with no keys, but bid on if they have three keys:
- 6 of trumps shows three keys, no outside king nor QT
- 5NT shows three keys, no outside king, but with the QT held
- anything else is a cue bid showing an outside king as above.