Polling You #46: Slam Bidding – Gerber, Day 6, February 28, 2011

Gerber Convention: Slam Bidding in Contract Bridge


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With the Blackwood 4 Notrump convention in our arsenal to handle slam bidding in a suit contract, we are ready to explore the intracasies of the Gerber 4 Club convention.

When our partner has either opened our rebid a Notrump bid without a partnership suit fit, we need an alternative tool to check for Aces before bidding a Notrump slam.  And that’s where our friend the 4 Club Gerber comes into action.  Okay, let’s try the poll and watch our video commentary.

Slam Conventions: Blackwood and Gerber

With good shape (a long suit partnership fit), we often use the Blackwood Convention – 4 Notrump to search for slam in a suit contract.

With a more balanced hand, we typically use the Gerber Convention – 4 Clubs is used to search for slam in a Notrump contract (or possibly a suit contract when partner attempts to signoff in Notrump).

Like a suit slam contract, in a Notrump contract we appreciate the value of controls – Aces and Kings.  However, unlike a suit slam where a singleton or void might be particularly helpful, in a Notrump contract short suits are liabilities.

Gerber prerequisites:

Small slam, 12 tricks with 3-4 Aces/controls, 33+ distribution points

Grandslam, 13 tricks with 3-4 Kings/controls, 37+ distribution points

Typically a balanced hand (preferably not 4-3-3-3)
Perhaps a promotable long minor suit

Invoked after Notrump, continuing with a 4 Clubs conventional ask-asking bid 

Purpose of Gerber 4 Club bid:

Explore small slam – Bid 4 Clubs to ask, ensure sufficient Aces

Explore grandslam – Bid 5 Clubs to ask, promise all 4 Aces, ensure sufficient Kings
Captain and Crew:

Crew – limited strength shown by bidding. 

Open or respond Notrump:
1D – 1N;

Bid partners suit, signoff / invitational bid:
1H – 3H;

Opener rebid own/partner suit, signoff
1H – 1S; 2H / 2S

Responder rebids prior suit, signoff
1D – 1H; 1S – 2D / 2H / 2S

Captain – Unbounded strength, forcing bids

Open 1 level = 12-21 points

Respond in new suit = unlimited points

Strong Jump Shift = 1D – 2S    17+ points

Strong opener = 2C    22+ points

Gerber responses after 4 Clubs, as  2N – 4C:

4D = 0 or 4 Aces (first step)

4H = 1 Ace (second step)

4S = 2 Aces (second step)

4N = 3 Aces (third step)

Avoid the 4C response “Gotcha”

When responding to the 4C Gerber bid, be extra careful to remember that 4 Diamonds is the first step, showing 0 or 4 Aces.  Newer players tend to confuse Blackwood and Gerber responses which are physically on suit rank different.

Typical Gerber 4 Club examples:

1N – 4C

2N – 4C

1D – 2C;
2N – 4C;

2C – 2N;

1D – 1H;
2C – 2S;
2N – 4C

Gerber continuations after 4 Clubs response followed up by 5 Clubs:
2N – 4C;
4S – 5C;

5D = 0 – 4* Kings (first step)

5H = 1 King (second step)

5S = 2 Kings (third step)

5N = 3 Kings (fourth step)

*Some prefer to use 6C to show 4 Kings

Gerber continuation bids:

1D – 1H;
2N – 4C;
4S                 2 Aces

2N – 4C;
4N – 5C;      3 Aces, King ask (responder 1 Ace)
5H – 6N;      1 King

1D – 2C;
2N – 4C;
4D – 4S;       0/4 Aces, responder forces signoff in Notrump


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Warm Regards,



  1. richbria says:

    Some of my Beginner Students wonder about the 4 Diamond response showing 0 or 4 Aces. I ALWAYS have two comments about this question: (1) If you cannot work out whether partner has 0 or 4 Aces you should NOT be using this convention, and (2) very seldom will you be using Gerber if you have NO Aces in YOUR hand.

  2. warrenwolff says:

    So, in the 3 NT Limit Bid (13-15 HCP) sequence what is the meaning of 4 C/4 NT bids?

    North East South West
    1 C P 3 NT P
    4 NT

    Would a 4 C bid be Gerber? Or is this 4 NT a BW request?

    Think I will get varied answers.


    • gogogo says:

      4 clubs would be Gerber.
      4NT is a quantitative bid asking partner to go to 6NT with extra values or if not, pass.

    • BridgeHands says:
      Hi Warn, Gogogo, and Bob,
      Warren, interesting you should ask the question – coincidentally the topic of your question was covered in the upcoming Polling You #47, Gerber part 2. Gogogo and Bob said it well – 4 Notrump after 3 Notrump is Quantitative Blackwood. So in your auction, to ask for Aces, partnership agreements vary:
      4C is Stayman, 5C is “Super Gerber ask ask
      4D is Stayman, 4C is Gerber (apparently transfers are “off” for these folks)
      So indeed Warren, you’re correct that people have different views on the best conventional treatment. And since this auction seldom occurs, most folks don’t stay up late at time trying to get consensus on a ubiquitous agreement.
      Warm Regards, Michael
  3. Bob Noyes says:

    No not blackwood, it’s cumilitive asking partner to bid 6NT if maximum or pass if minimum

  4. BridgeHands says:
    Hello Bridge Pollsters,
    Well, Bridge Pollsters, we have a consensus on our Polling You survey question:
    Select the best answer regarding the Gerber Ace-asking convention.
    7 percent: 1N – 4C asks opener to conventionally respond with number of Aces
    0 percent: 1N – 4C; 4S shows 2 Aces
    23 percent: Both of the above
    3 percent: 1N – 4C; 4S – 5C partnership has 4 Aces, opener now shows the number of Kings
    67 percent: All of the above
    So perhaps about one-third of our pollsters would prefer not to use a follow-up 5C bid to check for Kings on the way to bidding a grandslam. Or maybe a few missed the point that the third step shows two Aces (Diamonds = 0, Hearts = 1, Spades = 2), a common slip for anyone to make – especially when away from the table.
    We have another Gerber poll coming up soon – stay tuned!
    Warm Regards, Michael

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