Roman Keycard Blackwood
Roman Keycard Blackwood — 4NT asks for the 5 keycards (4 aces + trump king) and the trump queen.
What Is Roman Keycard Blackwood?
The Five Keycards
Roman Keycard Blackwood (RKCB) is the modern evolution of the classic Blackwood 4NT convention. Instead of asking for four aces, RKCB asks for five keycards: the four aces plus the king of the agreed trump suit. The trump king is elevated to keycard status because, for slam purposes, it is just as critical as an ace — it controls the trump suit and prevents the opponents from drawing trumps against you. A bid of 4NT, once a trump suit is firmly agreed, is the question: "How many of these five critical controls do you hold?"
The 1430 Variant
The most widely played version in Standard American today is called 1430, named for what the first two responses encode. After 4NT: 5♣ = 1 or 4 keycards, 5♦ = 0 or 3 keycards, 5♥ = 2 keycards without the trump queen, and 5♠ = 2 keycards with the trump queen. The label "1430" reminds you: 5♣ encodes 1 & 4, 5♦ encodes 3 & 0. Because you hold some keycards yourself, you can always deduce which interpretation applies to partner's ambiguous answer of 1-or-4 or 0-or-3 by counting what you hold.
The Other Variant: 3014
Some partnerships play 3014 (also called "0314"), where 5♣ = 0 or 3 and 5♦ = 1 or 4 — the reverse assignment. The 3014 version was historically common in Europe and among players who learned classical Blackwood first. The mechanics are identical; only the response assignment is flipped. When playing with a new partner, always confirm which variant is in use — this is one of the most common disasters at the bridge table.
Follow-up Bids
RKCB does not stop at the first response. After a 5♣ or 5♦ response, the asker can continue to probe: 5NT asks for specific kings (6♣ = king of clubs, 6♦ = king of diamonds, etc.), and bidding the cheapest non-trump suit asks specifically whether partner holds the trump queen. The entire structure is designed so that a partnership can identify exactly which controls they hold before committing to a small or grand slam — provided the trump suit is agreed before 4NT is ever bid.
Core Rules
Responses to 4NT (1430 Variant)
| Response | Meaning (1430) | Notes |
|---|---|---|
| 5♣ | 1 or 4 keycards | Asker deduces which from own hand |
| 5♦ | 0 or 3 keycards | Asker deduces which from own hand |
| 5♥ | 2 keycards, NO trump queen | Slam possible if asker has enough values |
| 5♠ | 2 keycards, WITH trump queen | If trumps are ♠, this forces the 6-level — see caution below |
Follow-up Bids After 5♣ or 5♦
| Bid by Asker | Meaning | Partner's Reply |
|---|---|---|
| 5NT | All keycards accounted for — ask for specific kings | 6♣=♣K, 6♦=♦K, 6♥=♥K, 6♠=♠K; 6NT=no side kings; may show extra controls |
| Cheapest non-trump suit | Trump queen ask | Next cheapest step = No queen; any other bid = Yes + shows that king |
The Queen Ask in Detail
After 4NT – 5♣ (1 or 4 KC), if trumps are hearts, the cheapest non-trump suit is 5♦. Responder answers: 5♥ = no trump queen; 5♠, 5NT, or 6♣/6♦ = yes, I have the trump queen, and this specific king too. The skip in the response tells you which king they hold alongside the queen.
Specific Kings via 5NT
5NT is only bid when the asker knows all five keycards are present. It asks partner to name their side-suit kings in ascending order. Responses: 6♣ = king of clubs, 6♦ = king of diamonds, 6♥ = king of hearts, 6♠ = king of spades, 6NT = no side kings. Some pairs use responses to show multiple kings; agree in advance.
Exclusion RKCB (Void)
When the asker holds a void, a direct jump to 5 of a new suit below trumps (not NT) is Exclusion RKCB, asking for keycards excluding the ace of that suit. For example, with spades agreed and a club void, jump to 5♣ (Exclusion). Responses follow the same 1430 pattern but exclude the ♣A from the count. This requires prior partnership agreement and careful judgment about when to use it.
Interference by Opponents (DOPI / DEPO)
| Method | After Interference Over 4NT |
|---|---|
| DOPI | Double = 0 or 3 keycards; Pass = 1 or 4 keycards; next available step = 2 without Q; etc. |
| DEPO | Double = Even number of keycards; Pass = Odd number of keycards |
DOPI is standard in most partnerships. DEPO is simpler but less precise. Both require explicit agreement.
Decision Tree
Use this tree to navigate RKCB decisions from the moment you consider bidding 4NT through to the final slam decision.
Quiz
Test your understanding of RKCB. Click an answer to see the explanation.
Revised answer: a — sign off in 5♠. You hold 3 keycards; partner's 5♦ must show 0 (since 3+3=6 is impossible). Combined = 3 of 5 — you are missing 2 keycards, including the ♠A. Do not bid slam.
Hand Examples
Example 1: Classic RKCB Small Slam
♠ A K J 7 5
♥ A Q 4
♦ K 6 5
♣ Q 4 3
19 HCP — opens 1♠
♠ Q 9 6 2
♥ K 5 4
♦ A Q 4
♣ A J 5
16 HCP
| North | South | Notes |
|---|---|---|
| 1♠ | 2♣ | 2/1 GF response |
| 2♠ | 3♠ | Setting trumps; inviting to explore further |
| 4NT | 5♥ | RKCB; 5♥ = 2 keycards, no ♠Q |
| 6♠ | — | North counts: own keycards ♠A, ♥A = 2. South shows 2 more (♦A, ♣A). Combined = 4 of 5; missing ♠K... wait, South holds ♠Q not ♠K. Let's recount: keycards are ♠K (trump king), ♥A, ♦A, ♣A, ♠A. North has ♠A, ♥A = 2 keycards. South has ♦A, ♣A = 2 keycards. ♠K (trump king) is with North (not a separate keycard from ♠A — wait, ♠K is a separate keycard). North: ♠A (1) + ♥A (2) = 2 keycards. Hmm, where is ♠K? South holds ♠Q, not ♠K. So ♠K is not accounted for. North = ♠A, ♥A = 2 KC. South = ♦A, ♣A = 2 KC. That is 4 of 5; ♠K is missing. South responded 5♥ = 2 KC no Q. Combined = 4. Slam is risky missing a keycard. Let's adjust hand. |
Revised hands for clean example:
♠ A K J 7 5
♥ A Q 4
♦ K 6 5
♣ K 4 3
Keycards: ♠A, ♠K (trump king), ♥A = 3 keycards
♠ Q 9 6 2
♥ K 5 4
♦ A Q 4
♣ A J 5
Keycards: ♦A, ♣A = 2 keycards (no ♠Q)
| North | South | Notes |
|---|---|---|
| 1♠ | 2♣ | 2/1 GF response, showing clubs and GF values |
| 2♠ | 4NT | Spades agreed; South asks RKCB |
| 5♦ | — | North shows 0 or 3 keycards. South holds 2, so 2+3=5 ✓ or 2+0=2 ✗. North must have 3 (♠A, ♠K, ♥A). South bids 6♠. |
| — | 6♠ | All 5 keycards present. 6♠ is an excellent contract. |
Key Point: South held 2 keycards. North's 5♦ (0 or 3) must be 3, since 2+0=2 means missing 3 keycards — clearly wrong with North's strong opening hand. Arithmetic solves the ambiguity.
Example 2: Knowing When NOT to Bid 4NT
♠ A K Q 7 5
♥ 4 3
♦ K Q 4
♣ A 5 4
Tempted to ask RKCB
♠ J 9 6 2
♥ K Q J
♦ 5 3 2
♣ Q 7 6
Would respond 5♦ (0 or 3) — actually 1 keycard: ♥K? No, ♥K is not a keycard for spades. South has 0 keycards.
North is tempted to bid 4NT (RKCB), but should first ask: what is my plan if partner shows 0 keycards? With North holding 3 keycards and partner holding 0, slam is off. Worse, if partner holds ♠J96x, the trump suit is soft. Here, North should simply jump to 6♠ based on self-sufficient strength, or sign off at 4♠ if not confident. Bidding 4NT only makes sense if you have a specific plan for each response.
Common Misunderstandings
Playing 1430 when partner expects 3014 (or vice versa) is catastrophic. In 1430, 5♣ = 1 or 4; in 3014, 5♣ = 0 or 3. A single-step difference means you may bid a grand slam with only 3 keycards or stop in game with all 5. Fix: Discuss the variant before every session and mark it clearly on your convention card.
Without trump agreement, 4NT is not RKCB — it's natural (quantitative Blackwood asking for aces) or a quantitative invite to slam. If your partner responds as if it were RKCB, the auction collapses. Fix: Always set trumps before bidding 4NT. Use a cuebid, raise, or Jacoby 2NT to establish the suit first.
In 1430: 5♥ = 2 keycards WITHOUT the trump queen; 5♠ = 2 keycards WITH the trump queen. Confusing these causes you to either bid a queen-less slam or pass a makeable contract. Fix: Memorize the mnemonic — "the higher response is better" (5♠ > 5♥, and ♠ response includes the queen).
Standard RKCB does not account for voids. If you hold a void, partner's keycards include the ace you are void in — which is worthless. The correct tool is Exclusion RKCB (jump to 5 of the void suit). Using regular 4NT with a void leads to over-counting. Fix: Agree on Exclusion RKCB with your partner; use it whenever you hold a first-round void in a side suit.
Many players bid 4NT and then realize they don't know what to do after a 5♦ or 5♣ response. This leads to panicked bids or misbid slams. Fix: Before bidding 4NT, mentally run through every response (5♣, 5♦, 5♥, 5♠) and decide your action for each. Only bid 4NT if you have a plan for all four possibilities.
Practice Sequences
Study and quiz yourself on these six common RKCB auction types.
Sequence 1: Basic 1430 Response and Sign-off
| West | North | East | South |
|---|---|---|---|
| — | 1♠ | Pass | 2♥ |
| Pass | 3♥ | Pass | 4NT |
| Pass | 5♣ | Pass | 5♥ |
| 5♣ = 1 or 4 KC (1430). South holds 2 keycards (♥K trump king + ♠A). 2+1=3 or 2+4=6. Since 6 is impossible, North has 1. Combined = 3. Slam is off. South signs off in 5♥. | |||
Sequence 2: Trump Queen Ask After 5♦
| West | North | East | South |
|---|---|---|---|
| — | 1♥ | Pass | 2♣ |
| Pass | 3♥ | Pass | 4NT |
| Pass | 5♦ | Pass | 5♠ |
| Pass | 6♦ | Pass | 6♥ |
| 5♦ = 0 or 3 KC. South deduces 3 (from own 2 keycards). 5♠ = trump queen ask (cheapest non-trump suit after hearts). 6♦ = "Yes, I have the ♥Q and also the ♦K." South bids 6♥ — all controls confirmed. | |||
Sequence 3: Specific King Ask via 5NT
| West | North | East | South |
|---|---|---|---|
| — | 1♠ | Pass | 2♦ |
| Pass | 2♠ | Pass | 4NT |
| Pass | 5♥ | Pass | 5NT |
| Pass | 6♦ | Pass | 7♠ |
| 5♥ = 2 KC no ♠Q. South has 3 KC = combined 5 of 5. 5NT asks for kings. 6♦ = king of diamonds. South can count 13 tricks and bids 7♠. | |||
Sequence 4: Exclusion RKCB (Void)
| West | North | East | South |
|---|---|---|---|
| — | 1♠ | Pass | 2♥ |
| Pass | 3♠ | Pass | 5♦ |
| Pass | 5♥ | Pass | 6♠ |
| South holds a diamond void and spade fit. 5♦ = Exclusion RKCB (asks for KC excluding ♦A). 5♥ = 2 keycards (not counting ♦A). South knows all other controls are present and bids 6♠. | |||
Sequence 5: Sign Off After Bad Response
| West | North | East | South |
|---|---|---|---|
| — | 1♥ | Pass | 3♥ |
| Pass | 4NT | Pass | 5♣ |
| Pass | 5♥ | Pass | Pass |
| North has 2 keycards. 5♣ = 1 or 4. 2+4=6 impossible; partner has 1. Combined = 3 of 5. North signs off in 5♥. (5♥ is the trump suit bid = sign-off; it is NOT the trump-queen ask here because it IS the agreed trump suit.) | |||
Sequence 6: Grand Slam Try — All 5 Keycards Plus Trump Queen
| West | North | East | South |
|---|---|---|---|
| — | 1♠ | Pass | 2♣ |
| Pass | 3♠ | Pass | 4NT |
| Pass | 5♠ | Pass | 5NT |
| Pass | 6♥ | Pass | 7♠ |
| 5♠ = 2 KC + ♠Q (and spades are trumps — so this response commits to the 6-level). South holds 3 KC = combined 5 of 5. 5NT asks for kings; 6♥ = king of hearts. South has all the information needed for 7♠. | |||
Expert Mistakes
Experienced players sometimes bid 4NT at a point where even a sign-off response forces the partnership past 5 of the agreed suit. For example, after a complex auction where the agreed trump suit is a minor and the bidding is already at 4♠, bidding 4NT risks having to play at the 5-level with inadequate trumps or controls.
Fix: Before bidding 4NT, verify that every possible response leaves room to sign off at 5 of the trump suit. If not — don't ask. Use judgment and bid the slam or sign off directly.
Even at the expert level, players sometimes bid 4NT and then hesitate after the response — revealing that they didn't have a plan. This is unfair to partner and ethically problematic when hesitation conveys information. A good player mentally scripts every response before asking.
Fix: Before bidding 4NT, rehearse mentally: "If partner bids 5♣ I will... If 5♦ I will... If 5♥ I will... If 5♠ I will..." Only proceed if you have a clear, pre-decided action for every possible answer.
The whole elegance of RKCB is that the ambiguous responses (5♣ and 5♦) are always resolvable by arithmetic. Yet even experienced players sometimes fail to count their own keycards and ask unnecessarily, or worse, bid incorrectly because they forgot to deduce the unambiguous answer.
Fix: After any ambiguous response, immediately count your own keycards. You hold X keycards. Partner shows Y or Z. Only one option is arithmetically possible (since the total cannot exceed 5). Act on that deduction without hesitation.
A void in a side suit inflates the value of RKCB responses. If partner holds the ace of your void suit, it counts as a keycard but provides no trick. Experienced players who haven't discussed Exclusion RKCB can end up in slams that fail because the "ace" counted was opposite a void.
Fix: Agree with your regular partners on Exclusion RKCB. When you hold a void and want to ask for controls, use the jump to 5 of the void suit rather than 4NT. This removes the irrelevant ace from the count.
Convention Card Notes
RKCB — Slam Conventions
4NT = Roman Keycard Blackwood (1430)
Requires prior suit agreement (explicit or by strong inference).
| Response | Meaning |
|---|---|
| 5♣ | 1 or 4 keycards (1430 — "1" and "4" are the first two digits) |
| 5♦ | 0 or 3 keycards |
| 5♥ | 2 keycards, NO trump queen |
| 5♠ | 2 keycards, WITH trump queen |
| 5NT | Asks for specific kings (after 5♣/5♦ when all KCs accounted for) |
| Cheapest non-trump | Trump queen ask (after 5♣ or 5♦) |
Notes:
- Exclusion RKCB: jump to 5 of void suit (asks KC excluding that ace) — requires agreement
- Interference over 4NT: DOPI (Double=0/3, Pass=1/4) by default
- NOT RKCB: after 1NT opening (quantitative), without suit agreement
- Variant: 1430 (5♣=1/4, 5♦=0/3). Confirm with partner before play.