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Looking for Slams

Key Card Blackwood

This is the final check that we go through before bidding a slam, in order to be sure that our opponents can’t just take two tricks and defeat our contract. Find out how it works by watching the video, then practice using it in the quiz.

Try some hands

Hand 1

After cuebids from you and your partner which you learnt in the last module, your partner bids 4NT. You must pick the right response to show how many keycards you have. After the defence win the first club trick, you need to figure out a way to put that tempting club suit to use. Hint: it’s a type of finesse you might not have seen yet.

 Hand 2

You can jump rebid to 3♠ on the second round to show support and a very good hand. Your partner then bids keycard blackwood knowing you have all the controls between you. In the play you have a choice to finesse in clubs either way, but one is superior…

 Hand 3

Between you, you agree hearts and cuebid once each, so your partner is able to bid blackwood once they can see all the controls. Again, you must pick the right response. The hand is quite tricky, and you should be careful with your entries when finessing.

 Hand 4

With such a good hand, you can cuebid as soon as your partner agrees spades. After your partner cuebids in response, you need to decide whethe you can see all the controls for blackwood yet, or whether you should carry on cuebidding. Eventually, you must decide whether slam is a good contract or not.
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Looking for Slams: Key Card Blackwood

This clever convention lets you check you have all the important cards before you finally bid your most exciting contracts.

Question 1/7

Walter has a very nice hand, especially as his partner has opened the bidding. What should he bid here?

Walter has made a game forcing response and then agreed spades as trumps by bidding 2♠. Penelope then shows a control in clubs (Walter knows this will be a singleton or void, because he holds both the ace and king). Even though he has such a lovely hand, Walter should not bid 4NT key card, because he doesn't have a diamond control and Penelope has not had a chance to show one. He should bid 4♥ and wait to see what Penelope does next. If she signs off in 4♠ she won't have a diamond control either. If Penelope has a diamond control and bids 4NT Walter can now happily show his 3 key cards (A♥, A♣ and K♠) by bidding 5♦ (which shows 0 or 3 key cards).

Carrying on the same auction, Walter has bid 4NT as a key card enquiry. What does Penelope’s 5♥ bid show?

Remember your key card responses. First step (5♣) shows one, or one's pointy friend, four. Second step (5♦) shows zero or three (the round numbers), Then 5♥ is two without the queen (lower bid, worse situation) and 5♠ is two with the queen. So here, Penelope has two key cards and no queen.

Penelope has made the key card enquiry this time, with spades agreed as trumps. How many key cards does Walter have?

Walter's 5♦ response (second step) shows zero or three key cards. However, Penelope has three in her own hand (Ace and king of spades and ace of hearts). There are only five key cards in total, so it's impossible for Walter also to have three, and he must therefore have none.

Walter has bid 4NT as key card Blackwood here, but for which suit as trumps?

Where a suit has been bid and raised by the partnership, then that suit has been agreed as trumps. However, if no suit has been agreed in this way, then the key card enquiry is for the last suit bid, in this case, hearts, which Penelope has shown as her second suit and Walter is very enthusiastic about.

Should Penelope bid 6♠?

Walter's 5♣ response to the key card enquiry shows 1 key card (he can't have four because Penelope has three (Ace and king of spades and ace of hearts). That gives them four between them. Four key cards and the queen is enough to bid slam, but Penelope does not have the queen. If Walter had shown two key cards he would also have been able to show or deny the queen, but as he had only one, it remains unclear whether he has the queen.

In that same auction, Penelope can find out the missing information about that queen by making another bid. What is that bid?

When the response to a 4NT key card enquiry is 5♣ or 5♦, responder has not had a chance to show the queen of the trump suit. However, the 4NT bidder can ask about the queen if they need that information, by bidding the next suit up. In this case, where Walter's response is 5♣ (showing 1 or 4 key cards), the bid that asks for the queen would therefore be 5♦. If Walter has the queen of spades he should bid 6♠, and if not, he should sign off in 5♠.

What should Penelope bid now, after Walter’s response to her key card enquiry?

Penelope has asked about key cards and Walter has shown one or four by bidding 5♣. She knows it can't be four, because she has two. That means it's one, and so they only have three key cards between them, which is not enough to bid slam. Penelope should therefore sign off in 5♠.

These links will take you to the Bridge Training website, where you can have a go at bidding and responding to Key Card Blackwood. You will then be able to play the hands and see if you can make your contract. Have as many goes as you like if you don’t succeed the first time.