Bridge Tips No 9
Roman Key Card Blackwood (RKCB)
Old fashioned Blackwood uses a bid of 4NT to ask partner how many aces are held to avoid bidding a slam with two aces missing but if the following suit has been
established as the trump suit:
then, despite having all the aces, a slam is doomed to failure. Clearly, the king of trumps is a very important card when considering a slam and so too is the queen of trumps to a slightly lesser degree. RKCB is a modified version of the original Blackwood, designed to overcome the problem highlighted above. This is achieved by including the king of trumps as a fifth key card along with the four aces.
The responses to an RKCB 4NT are as follows:
5C = 0 or 3 key cards
5D = 1 or 4 key cards
5H = 2 key cards without the trump queen
5S = 2 key cards with the trump queen
So, if you hold:
and, after agreeing a trump suit, partner bids 4N (playing RKCB):
If spades are trumps you bid 5S = 2 key cards and the SQ
If hearts are trumps you bid 5H = 2 key cards without the HQ
If diamonds are trumps you bid 5C = 3 key cards
If clubs are trumps you bid 5C = 3 key cards
If all five key cards are held and the 4N bidder is interested in a grand slam he can bid 5N to ask for kings exactly as in Blackwood but, of course, there are only 3 kings to worry about since the trump king has already been accounted for. If the response to 4N is 5D or 5C (which say nothing about the trump queen) it is possible to ask about the trump queen by bidding the lowest available suit which is not the agreed trump suit. In response to this asking bid partner signs off in 5 of the trump suit without the trump queen and bids 6 if holding the trump queen.
Here is an example of RKCB in action:
West East W E
JT98 Q5432 The bidding: 1C 1S
86 AKQ5 2S 3H
A7 KQ6 4S 4N
AKJ62 7 5H 5S
West has shown a good 7 loser hand to which East adds his 4 losers to conclude that the hands are good for a small slam and maybe a grand slam. Using ordinary Blackwood the 5H bid shows that an ace is missing so East may bid 6S and go down because both the ace and king of trumps are missing. Using RKCB, East knows that two key cards are missing and signs off in 5S.