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Slam Bidding in Bridge

A slam in bridge is bidding and making 12 tricks and a grand slam is bidding and making all 13 tricks. Slams are fun!

grand slam in bridge

Grand Slam - for North and South!

How to bid a slam

Slams don't come around as often games or partscores and the score for making a slam is high so it can take some time to feel confident with 6 and 7 level contracts. You may have heard that you need to learn some special ace asking convention before you can bid a slam but it's really much simpler than that.

When you are considering bidding game the thing you really want to know is if you have enough overall strength. Generally, 25 points is enough to give your side a fair shot at making game. There's no guarantee that you'll make game with 25 points but you'll make it often enough that it's worthwhile bidding with that strength.

The first thing you need to figure out when you are thinking of bidding a slam is what your sides' combined strength is, just like you do when you're bidding game. How many points do you and partner have? Don't be tempted to leap into ace asking until you've worked out if you have enough points or overall strength for slam. Aces come later. In fact, if you have enough points for slam then you'll probably also have enough aces.

Points needed for slam in bridge

The strength of a hand depends on points, trumps, distribution, how well your honours are working together and various other things so it's not easy to give a number to what you need for 12 tricks but it's helpful to have a few guidelines. You'll be fairly safe if you use these numbers:

High Card Points (HCP)

  • 6♣, 6, 6, 6♠ - 31-32 HCP
  • 6NT - 32-33 HCP
  • 7♣, 7, 7, 7♠ - 35 HCP
  • 7NT - 37 HCP

So how do you know how many points your partner has? It's simple! You just stick to basic bidding technique. It's the early rounds of bidding at low levels that are the key to successful slam bidding.

easy slam bidding

Slam bidding is easy!

On the hand above, South's 1♠ bid paves the way to slam. 1♠ is a change of suit so it's forcing. That means North can't pass and is expected to describe his hand further which he does, in this case, with 2NT. That 2NT bid is a limit bid showing 18-19 points and a balanced hand. South has 15 high card points with good shape together with North's 18-19 making 33-24 between the two hands. North must have at least 2 spades for the 2NT bid so South can be sure of an 8 card trump fit. 33 points and 8 trumps - that's slam!

But don't we have to ask for aces? Nope. How many aces are you missing? There are 40 points in a pack of cards so with 33 of them your side can only be missing 7 points. Two aces equals 8 points. You can't be missing two aces.

Asking for aces too soon or even at all is the one thing that leads to more missed slams and more slams going down than anything else. Use basic bidding technique, the stuff you learned at beginners' lessons to work out your combined strength. That's how you bid a slam.

Limit bids

Limit bids show an exact point range and shape and are the cornerstone of all natural bidding systems. A 1NT opening bid is an example of a limit bid. For Standard players that shows 15-17 points and balanced hand. For Acol players it's 12-14 points and balanced. It's easy to know how high to bid when your partner makes a limit bid. You simply add your points to partner's and calculate the total. That total tells us whether to bid game, slam or stay in a partscore.

The quantitative 4NT bid in bridge is used when you have a strong balanced hand and you're not sure if your combined strength is enough for 6NT.

Hand Evaluation

Points alone are a big help in determining your partnerships' combined strength but there are other things to consider.

Trump fit

If you have a good trump fit then you'll often be able to make slam with 30 or even less combined points. However, with a trump fit, counting points may not be the best way to judge your strength. The losing trick count is much more accurate for deciding about games as well as slams.

Fitting Cards

How well your honour cards are working together makes a big difference. In the following hand, South has the K and J. Those cards are likely to combine well with North's shown diamond suit.

slam bidding in bridge

South loves those diamond honours!

Singletons can be a great help in a suit contract and knowing that your partner has a singleton can help you determine if your honour cards in that suit are going to be helpful or wasted.

A splinter bid in bridge shows trump support, a singleton or void in the suit bid and is invitational to slam.

Slam Bidding Conventions

Knowing your bidding system well and good hand evaluation will get you to most good slams and keep you out of the bad ones. Once you've determined your overall strength, you might need to check that you're not missing two aces.

An example of using Blackwood to stay out of a slam missing two aces.
Blackwood in bridge, 4NT asking for aces, is a convention useful for slam bidding when you're likely to end up in a suit contract.
Roman Key Card Blackwood (RKCB) is a variation of the Blackwood convention. 4NT asks for 'keycards' which are the 4 aces plus the King of trumps.
Cue bidding is a method of showing which aces and kings your side has. It can also be used to show singletons and void.
Gerber in bridge, 4♣ asking for aces, is a convention useful for slam bidding when partner's last bid was 1NT or 2NT.

Slam Bidding Practice Hands

Try these hands and videos to practice your slam bidding.

Game Slam or Grand Slam
Big hands are always fun!

Most Famous Slam Hand

The hand shown at the top of the page is from the James Bond movie, Moonraker. The evil Drax isn't happy sitting East when 7♣ makes. Nice, very nice.


Hi, I have looked to see how the 2NT shows 18-19 points. I thought 2NT bid was 15-16 points. Where to I learn the 2NT bid showing 18-19 points please.
Acol. 😊 Imoji for thank you.
Thank you Graeme. Printed it off to review it.
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