RKCB, Eddie Kantar-style — how to ask for key cards without detonating your partner's brain

A practical, slightly cheeky look at Eddie Kantar’s variant of Roman Key Card Blackwood (RKCB). It’s simple, sharp, and keeps your partnership sane — most of the time.

A bit of history

Eddie Kantar — legendary American bridge player, teacher, and author — refined countless bidding conventions for clarity and sanity. This RKCB variant is a perfect example: compact responses to 4NT that pack in all the key-card info and a nod to whether partner owns the trump queen.

The core of the system

When you bid 4NT as RKCB you are asking for the five key cards (the four aces plus the king of trumps). In this variant, responder’s steps are:

Response to 4NT	Meaning
5♦	3 or 0 key cards
5♣	1 or 4 key cards
5♥	Exactly 2 key cards, without the queen of trumps
5♠	Exactly 2 key cards, with the queen of trumps

💡 Note: this version swaps the usual order of 5♣ and 5♦ — if that’s your agreement, stick with it. Confused partners are expensive partners.

How trumps are defined

If a trump suit has already been agreed, RKCB refers to that suit. If not, the trump suit is the last naturally bid suit by the partnership (no splinters allowed in this definition).

Finding out about the queen of trumps

The “2 key card” responses tell you whether partner has the queen of trumps:

5♥ → 2 key cards without the queen
5♠ → 2 key cards with the queen

When to ask the queen question

If partner responds 5♣ or 5♦, you don’t yet know about the queen. Simply bid the next cheapest step to ask directly. If partner has the queen, they move up a step; if not, they stay put.

Example:
4NT — 5♣ — 5♦ (ask about the queen).
If partner has the queen, they bid 5♥; if not, they pass or bid the next logical negative.

Use of 5NT and follow-ups

After the key-card responses, 5NT is the “which kings?” ask. Once the trump queen is known, responder can show specific kings by bidding the cheapest available suit — another partnership agreement worth writing down before the post-mortem begins.

When to bid small slam, big slam, or stop

Missing two key cards → stop below slam, collect dignity.
Missing one key card but have the trump queen → small slam is fine, provided side values behave.
Missing one key card and no trump queen → small slam only if you have 10 trumps, or 9 trumps plus the jack. Otherwise, stay earthbound.
For a grand → all key cards in place, and if you hold 10 trumps even without the queen — go for it. Courage favours the bold (and the reckless).

Finding out about outside honours

Once you’ve settled the key cards, use cue-bids, 5NT king-asks, or agreed suit checks for any remaining high-card mysteries. When in doubt, take the safe route — nobody admires a bold minus-1400.

Two worked examples

Example A — agreed trumps: spades
Auction:

1♠ — 3♠ — 4NT

Responder holds: ♠ KQJxx, ♥ Axx, ♦ Kxx, ♣ xx (13 cards at last!).
That’s 2 key cards and the trump queen → respond 5♠.
Opener now knows: 2 key cards plus the queen — small slam looks very tempting.

Example B — last suit becomes trumps
Auction:

1♣ — 1♥ — 2♥ — 4NT

(Hearts are agreed as trumps.)
Responder holds: ♥ Axx, ♠ KQxxx, ♦ Axx, ♣ xx → that’s 2 key cards without the trump queen → respond 5♥.

Quick cheat-sheet (printable)

Bid	Short meaning
5♦	3 or 0 key cards
5♣	1 or 4 key cards
5♥	2 key cards, trump queen absent
5♠	2 key cards, trump queen present
5NT	Asks for kings

Kantar’s version: fast, logical, and just smug enough to make your teammates roll their eyes. Use it wisely — and try not to detonate any more brains than strictly necessary.