The Gerber Convention (4♣) in Bridge Bidding
How to ask for aces in notrump auctions without confusing partner
The Gerber Convention solves a critical problem in bridge bidding: how do you ask for aces when you're in a notrump auction? In suit auctions, you can simply bid 4NT (Blackwood) to ask for aces. But after partner opens or rebids notrump, a bid of 4NT is quantitative—it invites slam and asks partner to pass with a minimum or bid 6NT with a maximum. It does not ask for aces.
Gerber provides the solution: a direct jump to 4♣ over partner's 1NT or 2NT opening (or notrump rebid) is artificial and asks partner to reveal how many aces they hold. Because the asking bid is at the 4-level rather than the 4NT level, you get the ace count sooner and can still stop at 4NT if the answer is disappointing.
When to Use Gerber
Use Gerber (bid 4♣ directly over partner's notrump) when you have:
- Partner has opened or rebid 1NT or 2NT
- You have enough combined strength that slam is likely if aces are not missing
- You need to know the number of aces before committing to slam
- You are planning to play in notrump (not a suit contract)
Key Principles
- Gerber = 4♣ over notrump: A jump to 4♣ directly over partner's 1NT or 2NT opening or rebid
- 4NT over notrump = Quantitative: This invites slam—it does NOT ask for aces
- In suit auctions, use Blackwood: Gerber only applies over notrump bids. In suit auctions, 4NT (Blackwood) asks for aces
- Advantage: Responses start at 4♦, keeping the bidding low enough to stop at 4NT if you're missing two aces
Gerber Responses (Aces)
After you bid 4♣ (Gerber), partner responds:
| Response | Meaning |
|---|---|
| 4♦ | 0 or 4 aces |
| 4♥ | 1 ace |
| 4♠ | 2 aces |
| 4NT | 3 aces |
Asking for Kings (5♣)
After getting the ace count, bid 5♣ to ask for kings:
| Response | Meaning |
|---|---|
| 5♦ | 0 or 4 kings |
| 5♥ | 1 king |
| 5♠ | 2 kings |
| 5NT | 3 kings |
Only ask for kings if you have confirmed that all four aces are accounted for and are considering a grand slam (7NT).
Example Hand
Your Hand (South)
♥ A J 3
♦ K Q 8 7
♣ J 4 2
HCP: 15 | Shape: 3-3-4-3 | Combined points: 35–36 (slam is certain if aces are held)
The Auction
| North | South (You) | Explanation |
|---|---|---|
| 2NT | 20–21 HCP, balanced | |
| 4♣ | Gerber—"How many aces do you have?" | |
| 4♠ | "I have 2 aces" | |
| 6NT | Slam! With your ace and partner's 2, only 1 ace is missing—safe for small slam |
With 15 HCP opposite 20–21, you have at least 35 combined points—more than enough for 6NT. The only danger is missing two aces. Gerber confirms you're missing just one, so you bid slam with confidence. Note that bidding 4NT here would be quantitative (inviting slam), not ace-asking!
Common Mistakes
- Using 4NT as Blackwood over partner's notrump opening: This is the most frequent error. Over a 1NT or 2NT opening, 4NT is quantitative (inviting slam), not Blackwood. If you want to ask for aces, you must bid 4♣ (Gerber).
- Using Gerber in suit auctions: Gerber only applies as a direct jump to 4♣ over a notrump bid. In suit auctions, a bid of 4♣ is natural or a cuebid. Use Blackwood (4NT) to ask for aces in suit auctions.
- Confusing Gerber responses with Blackwood responses: Gerber responses go 4♦–4♥–4♠–4NT in steps. Blackwood responses (using standard or RKCB) follow a different structure. Make sure you and your partner are on the same page.
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