Blackwood Bridge Convention – How to Ask for Aces and Kings
Blackwood Bridge Convention – How to Ask for Aces and Kings
The Blackwood Convention is one of the most famous and essential bidding conventions in bridge.
It allows you to ask your partner how many Aces or Key Cards they hold when exploring a slam, helping partnerships reach great contracts while avoiding unmakeable ones.
If you’ve ever wondered what that mysterious 4NT bid means, this guide explains everything: what Blackwood is, how it works, when to use it, and how to practice it online.
What Is the Blackwood Convention
The Blackwood Convention is a bidding tool used after a trump suit fit has been established and you believe a slam (12 or 13 tricks) might be possible.
When you bid 4NT, you are asking your partner to reveal how many Aces they hold.
This information helps you decide whether to stop at game, bid a small slam (6-level), or aim for a grand slam (7-level).
The convention was created by Easley Blackwood in the 1930s and remains a fundamental part of modern bridge bidding systems.
How the 4NT Ask Works
After your side agrees on a trump suit, bidding 4NT is recognized as the Blackwood Ace-asking bid.
Your partner replies according to how many Aces they hold:
| Response | Meaning | Example Auction |
|---|---|---|
| 5♣ | 0 or 4 Aces | 1♥ – 3♥ – 4NT – 5♣ |
| 5♦ | 1 Ace | 1♥ – 3♥ – 4NT – 5♦ |
| 5♥ | 2 Aces | 1♥ – 3♥ – 4NT – 5♥ |
| 5♠ | 3 Aces | 1♥ – 3♥ – 4NT – 5♠ |
Once you know the partnership has all four Aces, you can safely continue to 5NT to ask for Kings, determining if a grand slam is possible.
Asking for Kings with 5NT
The 5NT bid is a continuation of the Blackwood Convention, but it is not automatic after asking for Aces.
You only bid 5NT when your partnership already holds all four Aces and you are exploring the possibility of a grand slam.
By bidding 5NT, you ask partner to show how many Kings they hold, using the same step structure:
| Response | Meaning |
|---|---|
| 6♣ | 0 or 4 Kings |
| 6♦ | 1 King |
| 6♥ | 2 Kings |
| 6♠ | 3 Kings |
Because some responses can push the contract beyond the six-level, you should only use 4NT or 5NT when you are already committed to reaching at least a small slam.
Be aware that after asking for Aces with 4NT, it’s possible to receive a response that forces play at the 6-level — even if you are missing two Aces.
Knowing both the number of Aces and Kings allows you to judge if the partnership has enough combined power to reach 13 tricks confidently.
When NOT to Use Blackwood
Even though it’s one of the most powerful conventions in bridge, Blackwood should be used with caution.
There are situations where using 4NT can actually create problems instead of solving them.
Avoid using Blackwood when:
- You or your partner have a void, since the Ace response may not give you the answer you need — what matters are the Aces in the suits where you don’t have the void.
- You haven’t confirmed control in all side suits.
The 4NT Ace ask should only be used after both partners have shown “controls,” meaning no suit where the opponents can immediately win two tricks.
This is usually done through control cuebidding, where players bid side suits to show first- or second-round control (Ace, King, singleton, or void).
Once these controls are established, 4NT can safely confirm Aces before committing to a slam.
Beginner tip: If you’re not familiar with cuebidding yet, aim for a combined 32+ high-card points (HCP) before thinking about a slam, and simply make sure you’re not missing two Aces.
-
You risk being forced too high.
In some auctions, for example when clubs are the agreed trump suit, partner’s Blackwood response may push you to the six-level even if you discover you’re missing two Aces.
Always ensure that a 4NT ask won’t take your side beyond a safe level if the answer isn’t what you hoped for. -
No trump suit has been agreed.
In that case, 4NT is quantitative, not Blackwood. -
You lack the strength for a slam and are simply “curious.”
Blackwood should only be used when a slam is a realistic possibility based on combined strength and fit.
The key principle:
Use Blackwood only when your partnership has the strength, the controls, and the safety to explore slam confidently.
Example Auctions
Example 1 – Exploring a Small Slam
1♥ – 2NT
4NT – 5♦ (1 Ace)
5NT – 6♦ (1 King)
6♥ – Pass
Meaning: The partnership has game-forcing values with 4+ card support, holding all but one Ace and one King — enough for a small slam in hearts.
Example 2 – Avoiding a Bad Slam
1♠ – 3♠
4NT – 5♣ (0 Aces)
5♠ – Pass
Meaning: Partner shows no Aces, so you wisely stop at game instead of risking a slam.
Blackwood vs Gerber – What’s the Difference
| Convention | Used After | Ask Bid | Purpose |
|---|---|---|---|
| Blackwood | Suit agreement | 4NT | Asks for Aces (and Kings) |
| Gerber | Notrump openings | 4♣ | Asks for Aces (and Kings) |
In short:
Use Blackwood when you’ve agreed on a suit.
Use Gerber when the auction started with 1NT or 2NT and you don’t hold a 4-card major.
If you do, go through 2♣ Stayman first to look for a major fit before using Gerber.
Variations and Extensions
Several modern variations build on classic Blackwood, adding precision for advanced partnerships:
-
Roman Key Card Blackwood (RKCB): A version that counts five key cards — the four Aces plus the King of trumps.
The Queen of trumps is not a key card itself but helps distinguish between certain responses (for example, 5♥ vs 5♠) to clarify whether the partnership holds the trump Queen. -
Exclusion Blackwood: Used when you hold a void.
It is made once a fit has been established, using a jump bid to ask partner how many Aces they hold, excluding the Ace in the suit they just bid by jumping. -
Kickback: Uses 4 of the next suit above the trump suit as the Ace-asking bid, saving valuable bidding space and avoiding the risk of going beyond a safe level.
While these are advanced conventions, mastering standard Blackwood first provides the foundation you’ll need to understand these refinements later.
How to Practice Blackwood on Bridge Champ
Bridge Champ lets you practice bidding conventions like Blackwood directly online.
You can:
- Create custom deals in Deal Source that focus on slam exploration.
- Review auction histories to see if the Blackwood 4NT ask was correctly used.
- Play solo practice games against bots and apply your bidding skills under real game conditions.
- Use your camera and microphone to replicate an authentic table feel while playing with your partner.
This makes it the perfect environment to refine your judgment and develop partnership understanding.
Start Practicing Bridge Conventions on Bridge Champ
Common Mistakes with Blackwood
-
Using 4NT with no suit fit.
Without an agreed trump suit, 4NT is quantitative, not Blackwood. -
Asking with weak hands.
Don’t use 4NT just because you’re curious — only when a slam is truly possible. -
Forgetting about voids.
When you or partner have a void, switch to cue-bidding instead. -
Not stopping soon enough.
Always check you have all four Aces before bidding beyond 5NT.
Final Thoughts
The Blackwood Convention remains a cornerstone of modern bridge bidding.
By mastering how to ask for Aces and Kings, you’ll avoid unnecessary slams and make more confident, informed decisions.
Whether you play at a club or online, understanding Blackwood will dramatically improve your partnership’s accuracy and success rate.
Ready to test your bidding skills?
Join live tournaments and practice the Blackwood Convention today on Bridge Champ.
