Roman Key Card Blackwood


Roman Key Card Blackwood (Key Card, RKC, RKCB, 0314, 1430) is a variation of the Blackwood convention. It is used when the partnership has agreed to a trump suit and is interested in slam. A 4NT bid asks partner how many "key cards" he holds. A key card is any ace or the trump suit king.

There are two versions of RKC: 0314 and 1430 ("Fourteen-Thirty"), which refer to the step responses below.

Responses to 4NT


Playing 0314:

5 shows 0 or 3 key cards.
5 shows 1 or 4 key cards.
5 shows 2 or 5 key cards without the trump queen.
5 shows 2 or 5 key cards with the trump queen.


Playing 1430:

5 shows 1 or 4 key cards.
5 shows 0 or 3 key cards.
5 shows 2 or 5 key cards without the trump queen.
5 shows 2 or 5 key cards with the trump queen.

The 4NT bidder can usually (!) determine if responder has 0/3, 1/4, or 2/5 key cards.

Void-showing responses

5NT  shows an even number of key cards and an unspecified void.
6 shows an odd # of key cards and a void. If clubs are trumps, then it shows a void in another suit.
6 shows an odd # of key cards and a void if hearts or spades are trumps. If diamonds are trumps, then it shows a void in a higher suit (hearts or spades).
6 shows an odd # of key cards and a void if spades are trumps. If hearts are trumps, then it shows a void.

It is important to agree with partner when RKC is on, and when it is off. Sometimes one player wants to just ask his partner how many real aces he holds, and this can cause a lot of confusion at a precarious bidding level.

Origins


Roman Key Card Blackwood was initially based on Roman Blackwood, a Blackwood variant that was used by the famous Italian Blue Team in the 1960s. American expert Eddie Kantar is credited with popularizing the "key card" nature of the convention thereafter.

References


1 Bergen, Marty (2008). Slam Bidding Made Easier. Note: Mention "BRIDGEBUM" when buying this book directly from Marty to get 2 softcover books free.

2 Kantar, Eddie (2003). "A Key Question." ACBL Bulletin, January 2003.

Asking for Kings (5NT)


A 5NT rebid asks partner for kings. It is a grand slam try, and should only be bid if the partnership holds all 5 key cards and the queen of trumps.

There are two ways to play 5NT:

  1. To ask partner to bid his cheapest (non-trump) king.

  2. To ask partner how many kings he holds (standard Blackwood responses):
      6 - 0 kings.
      6 - 1 king.
      6 - 2 kings.
      6 - 3 kings.

An example auction playing RKCB with the 5NT "cheapest" king-ask:

OpenerResponder
KSA65
HAQT754K632
DA5K6
CAQ54J932

Opener    
1
4NT (1)
5NT (3)
6 (5)

Responder    
3
5 (2)
6 (4)

  1. RKCB for hearts.
  2. 2 key cards without the Q.
  3. Asking for partner's cheapest king.
  4. Showing the K.
  5. Signing off because of the missing K.

Asking for the Trump Queen


The 5 or 5 replies don't indicate whether responder holds the queen of trumps. The 4NT bidder can bid the cheapest non-trump suit to ask this question. The responses to the queen-ask are:

Bidding the trump suit   No trump queen
5NT The trump queen, but no kings (the king of trumps doesn't count)
Bidding any non-trump suit   The trump queen AND the king of that suit

An example auction playing RKCB 1430 with a queen-ask:

OpenerResponder
AJT75SK93
HAKTQ3
DAKT2J8
C5KQ7642
Opener    
1
3
4NT (1)
5 (3)
Pass

Responder    
2
3
5 (2)
5 (4)

  1. RKCB for spades.
  2. 1 key card.
  3. Asking for the Q.
  4. Denies the Q.

Why You Should Play 1430 vs. 0314


American expert Marty Bergen says that he asked 60 top pairs which Blackwood variant they use. 8 use plain Blackwood, 8 use RKC 0314, and an overwhelming 44 use RKC 1430. 1

Why is this? Eddie Kantar, author of "Roman Keycard Blackwood: The Final Word", theorizes that RKCB is usually used when a "strong" hand is interested in slam, and wants to ask the "weak" hand for key cards. As a corollary:
"One of the beauties of using Roman Key Card Blackwood instead of regular Blackwood is that it allows the 4NT bidder to ask partner whether he holds the queen of the agreed suit, as well as for other goodies. (Ed. note: See 'Asking for the Trump Queen', above.) To do this economically the asker needs room. The optimal response to 4NT, therefore, is 5 (as opposed to 5) allowing a follow-up bid of 5 to become the queen-ask.

"Playing 0314, a 5 response shows zero or three. '3' is a highly unlikely response when the stronger hand asks the weaker hand, so the 5response figures to show "0".

"After a zero response the asker usually signs off. The end result is that a 5 response seldom leads to any further asks.

"Playing 1430 the 5 response shows one or four. It doesn't take a rocket scientist to work out that it shows '1'. Now if the asker wishes to ask for the queen, 5 is available. This lower step is especially important when hearts is the agreed suit. Now the queen-ask can be made beneath the five level of the agreed suit.

"Playing 0314, the '1' response is 5, preempting the asker out of a lower-level queen-ask if hearts is the agreed suit. Clearly 1430 works best when the strong hand asks the weak hand."2

RKCB In Competition


See ROPI when the opponents double 4NT. Redouble shows 0, 3 or 5 keycards while Pass shows 1 or 4 keycards.

There are a number of ways to show key cards if 4NT is overcalled. One way is called DOPI, which stands for "Double = 0 (or 3 or 5) key cards, Pass = 1 (or 4)." The cheapest available bid shows two key cards, the second-cheapest bid shows three key cards, and the third- cheapest bid shows four.

Another method of showing key cards is DEPO, which stands for "Double = Even number of key cards, Pass = Odd number of key cards."