Roman Key Card Blackwood: 1430 and 3014 Explained

Roman Key Card Blackwood (RKCB) is a 4NT ask for five key cards: the four aces plus the king of the agreed trump suit. In the popular 1430 version partner answers 5♣ with 1 or 4 key cards, 5♦ with 0 or 3, 5♥ with 2 and no trump queen, and 5♠ with 2 and the trump queen.

It replaced plain Blackwood in most tournament partnerships because the trump king and queen matter as much as the aces. A slam missing one ace and the trump king is a bad slam, and plain Blackwood cannot see that. RKCB is part of nearly every modern 2/1 Game Force and Standard American card, and Acol players use it just as widely.

RKCB only works when a trump suit is agreed, because the trump king is one of the key cards. If the auction has not agreed a suit, most partnerships treat the last bid suit as trumps.

Once 4NT is bid, partner counts his key cards: each ace is one, and the trump king is one more, for a maximum of five. He also notes whether he holds the trump queen. Then he answers in steps.

The asker, as in plain Blackwood, is the captain. He chooses the contract; partner answers questions and accepts the sign-off. You can see what 4NT means in every system in this heart auction.

There are two common orders for the first two steps. The third and fourth steps are the same in both.

The names come from the first two steps: "14-30" means 5♣ shows one or four, and 5♦ shows three or zero. 3014 reverses them.

Many American partnerships play 1430, others prefer 3014, and some use one order for majors and the other for minors. Any of these works if both of you play the same one.

The "or" answers are almost never a problem: the asker knows his own key cards and the auction, so only one of the two counts makes sense.

The queen ask. After a 5♣ or 5♦ answer, partner has not told you about the trump queen. To ask, bid the cheapest suit that is not the trump suit. With spades agreed, after 5♣, 5♦ asks; after 5♦, 5♥ asks. With hearts agreed, after 5♣, 5♦ asks; after 5♦, the next suit is hearts (a sign-off), so 5♠ asks.

Partner answers:

• Without the queen: bid the trump suit at the cheapest level.
• With the queen: bid the cheapest side suit where he holds the king, or 5NT with the queen and no side king. (Some pairs simply jump to six of trumps with the queen.)

With a known ten-card fit, many partners answer "yes" without the queen, because it usually falls anyway.

The king ask. 5NT asks for side kings. It promises that your side holds all five key cards and the trump queen, so partner knows a grand slam is in view. The common modern answer is to bid the cheapest side king, with six of trumps denying any. Some partnerships count kings instead (6♣ = 0, 6♦ = 1 and so on). Do not count the trump king again: it was already shown as a key card.

Answers with a void. With a useful void, partner can show it: 5NT shows 2 or 4 key cards and a void; six of the void suit (when it ranks below trumps) shows 1 or 3 key cards and that void; six of trumps shows 1 or 3 key cards and a void in a higher suit. Only show a void the asker can use.

You are South and hold ♠AK5, ♥KJ74, ♦AQJ6, ♣K3: 21 HCP. Partner opens 1♥. You bid Jacoby 2NT, a game-forcing heart raise, and partner bids 4♥ to show a minimum with no shortness. You have three key cards: the ♠A, the ♦A and the ♥K. Slam is likely if partner has the ♥A or the ♣A, so you ask.

Partner's 5♣ must be one key card, not four: you hold three yourself. Five minus four is one missing, so the grand slam is out. The small slam also needs the trump queen, and you hold only the ♥J, so ask with 5♦, the cheapest suit that is not trumps (see what 5♦ means in every system). Partner bids 6♦: "I have the ♥Q, and my cheapest side king is the ♦K". Now 6♥ is right.

Before you bid 4NT, check that no side suit has two fast losers. Here the clubs are ♣K3 opposite ♣Q72, so the defense can take only the ♣A.

A grand slam with the queen ask. Now spades are trumps. Partner opens 1♠, you bid Jacoby 2NT, and he shows extras with 3♠. You hold two key cards and bid 4NT. Partner answers 5♦: three key cards in 1430, so your side has all five. You bid 5♥, the queen ask. Partner bids 6♣: "I have the ♠Q, and my cheapest side king is the ♣K". With all five key cards, the trump queen, the ♣K and enough tricks in your own hand, you bid 7♠.

1. Asking when you should cue bid. RKCB counts key cards; it says nothing about which side suits are controlled. With two small cards in an unbid suit, start with control-showing cue bids.
2. Forgetting the trump king. Partner's ♠K is a key card when spades are trumps, not when hearts are.
3. Disagreeing about trumps. In an auction with two possible suits, agree that the last bid suit is trumps unless a fit was clearly set earlier.
4. Going past five of a minor. With clubs as trumps, a 5♥ or 5♠ answer is already above 5♣. Many partnerships use a lower ask for minor suits, such as Kickback or Minorwood, for that reason.
5. Answering with a void you should not show. A void in partner's long suit is often worthless. Show only a void that saves a loser.

• Kickback: the suit above trumps (4♥ with diamonds agreed, for example) is the key card ask, so the answers stay lower.
• Minorwood: four of the agreed minor asks for key cards.
• Exclusion Blackwood: a jump to the five level in a void suit asks for key cards outside that suit. See Exclusion Blackwood.
• DOPI and ROPI: how to answer when the opponents interfere over 4NT. See DOPI and ROPI.

Key card auctions reward careful counting. The BridgeDummy Bidding Room lets you bid random hands with EPBot robots and then review all four hands, so you can see whether your slam was missing a key card. When you want to know how good a slam really is, our free double dummy analyzer shows how many tricks each contract takes on the deal.

• Blackwood convention: the plain ace ask RKCB grew from.
• Exclusion Blackwood: asking for key cards with a void.
• Slam bidding: when to start looking for slam at all.
• Jacoby 2NT: a common way to agree a major before RKCB.