Slam Bidding

YMCA Bridge Lecture for BB3 Ch4 (April 11, 2017)

Our chapter for today — Audrey Grant’s Bridge Basics 3 series, Ch. 4 — tells how to avoid unmakeable slams. The chapter’s advice is to verify your HCP and controls by employing techniques and conventions such as cuebids, 4♣ Gerber, 4NT Quantitative, and 4NT Blackwood. The chapter shows the appropriate bids and responses for these informational requests. You may download this lesson in one of the three following formats:

  1. Paragraph: AG BB3 Ch4 Para
  2. Outline: AG BB3 Ch4 Note.docx
  3. Practice Hands: BeB Slam Bidding.docx
Quantitative Bidding

Theory: Statistical evidence shows that a small slam in notrumps is possible if the partnership holds a combined 33+ HCP. A grand slam in notrumps is possible with a combined 37+ HCP. In hands that are highly distributional, a grand slam is possible when Declarer holds as little as 10 HCP and 9 Length Points, while Responder holds as little as 0 HCP and 0 Dummy Points.

Grand Slam: If the bidding shows 37+ HCP, then a partnership knows it is missing at most a K. Before calling for a grand slam, the partnership could invoke a convention to determine whether they are missing a threatening K or just a QJ.

Small Slam: If the bidding shows 33+ HCP, then the partnership knows it is missing at most an AK. Before calling for a small slam, the partnership could invoke a convention to determine whether they are missing a threatening AK or just a QQJJJ.

4NT Quantitative: The bidding ladder has an “ask” that can inquire whether partner’s hand is a maximum. This is 4NT Quantitative. This bid requires the first partner (P1) to limit their hand, and for the other partner (P2) to determine that slam is possible if P1 is at the top of the range for their limit bid. For instance, an Opener of 1m-1NT would promise 12-14 HCP, an Opener of 1NT would promise 15-17 HCP, an Opener of 2NT would promise 20-21 HCP, and an Opener of 2C-2NT would promise 22-24 HCP. A Responder with 20 HCP, 17 HCP, 12 HCP, or 10 HCP, respectively, would know that 6NT had a reasonable chance at success. Provided that neither partner had confirmed a trump suit, a bid of 4NT asks an Opener to bid 6NT with a maximum (e.g., 13+, 16+, 21, or 23+ HCP).

Trump Slams: In suits, partners value their hands based on length points and dummy points. Opener with a 13-0-0-0 distribution could have 10 HCP, 9 Length Points, and 15 Dummy Points. Responder with a 0-5-4-4 distribution could have a zero fit, a Yarborough, 1 Length Point, and zero Dummy Points. Opener and Responder could make a grand slam in Spades. Opponents could make a grand slam in the other three suits, and depending on the lead, possibly in NT. Slam in a suit is much less precise to determine with math than is a slam in NT!

Unconfirmed Trumps: A suit need not be raised to be confirmed. If the first partner (P1) bids a suit and the other partner (P2) jumps to 4NT, that is an implied confirmation. If during their hunt for a fit, P2 bids a second major and P1 cuebids cheaply rather than raising either major, that too is a confirmation (of the 2nd major as trumps). Confirmation doesn’t stop either partner from bidding 4NT, but it does change the meaning from 4NT Quantitative to 4NT Blackwood.

Cuebids: A relay bid following a suit confirmation is a cuebid. It shows a control (A, K, s, or v). The cuebidder calls the lowest suit on the bidding ladder for which they have an appropriate control. For example, P1 has confirmed ♥ and P2’s next bid is a cheap ♣. P2 is denying a control in ♠ but promising one in ♣. If P1 has a ♠ control, P1 will show their next cheapest control, either a ♦ or ♥. Without a ♠ control, P1 will stop the cuebidding. P1 will place the contract in partscore or game.

4NT Blackwood

Inventor: Easley Blackwood invented his convention in the 1930s. Today the Blackwood Convention is useful in getting partners to abandon an unmakeable slam. AG explains that a partnership may have a dozen or more Playing Tricks, but if the Opponents win the first two tricks, the Opponents will set the Declarer. Blackwood alerts the partnership to any missing Aces and Kings.

How: A partnership begins by confirming a fit. P1 bids a suit and P2 raises that suit. Any later bid of 4NT after finding a GF is the Blackwood Convention, asking the other partner to report their aces in the first round and their Kings in the second round. AG has tables of the appropriate responses on pp. 146, 148, 156.

Alternatives: Blackwood may return useless information if one or both partners have a weak doubleton (Kx might be reported as a K but not be a stopper) or unreported void (v might not be reported, but could be an effective stopper in a suit contract). As an alternative, a partner may begin cuebidding. After a suit agreement, a new suit is a cuebid, which promises control of that suit and asks for control of any lower suits.

4 Gerber

Inventor: John Gerber invented his convention in the 1930s, following the similar Blackwood in form, responses, and purpose.

How: A partnership begins by opening in 1NT, 1m-2NT, 2NT, or 2♣-2NT. Before reaching 3♣, one partner must jump to 4♣ Gerber. A bid of 4♣ is not Gerber after (1) a previous natural bid of ♣, (2) no opening NT call, or (3) no jump. A Stayman sequence of 1NT-2♣-2♥-4♣ is Gerber as 1NT is an opening bid, 2♣ is not natural, and 4♣ is a jump. A sequence of 1♣-1NT-4♣ is not Gerber as ♣ have been bid as a possible trump suit and 1NT is not an opening. There are no possible intervening bids after a 2NT opening or response that would retain 4♣ as a viable jump response. There are no jump bids after a 3NT opening or response to arrive at 4♣. Consequently, once the auction crosses 2NT, no later bids will be jump bids to 4♣ Gerber. Other sequences including a NT opening with a 4♣ jump are the Gerber Convention, asking Partner to report their aces in the first round and their Kings in the second round. AG has tables of the appropriate responses on pp. 152, 157.

Alternatives: Blackwood is an alternative to Gerber. A partnership can zoom past Gerber if they are exploring (1) two 5cM using JTB, (2) one 6cm using JTB, or (3) one 6cM using TTB. When Gerber is off, Blackwood is still available from 3♣ to 4♠.

Ace Asking Concepts

Cooperation: If your stronger partner asks you for your aces, kings, or control cards, you may not feel like your hand is worthy of such heights. Nonetheless, boost your response to qualitative bids by giving extra weight to your AK combinations, confirmed values in partner’s suits, honor sequences, and high intermediate cards (T98).

Missing Many Honors: If your trump suit is ♦ and you are missing three aces, a partner might respond to Blackwood with 5♥, forcing you to 6♦ even when you have a known missing Ace. You should not gamble on an ask-asking bid if one of the possible responses is higher than your alternative game contract.

  1. Best eBridge: Log on, then choose Online Lessons, Slam Bidding. After completing the lessons, click on Bidding, Slam Bidding. There are 60 hands to bid. Some are the same deal, but you will alternate between being Opener and Responder. Hands 1, 2, 3, … are basic concepts. Hands 70, 69, 68, … are advanced.
  2. Click on Bidding, Conventions by Category, Constructive Bidding, Slam Bidding. There are 12 slam topics, including one about Gerber and five about several types of Blackwood.
Tests of Comprehension
  1. How High: For a test on NT quantitative bids, go to Quiz 1 (p. 158). Try a, b, c, h.
  2. Blackwood: For a test on ace-asking Blackwood, go to Quiz 2 (p. 160). Try e, f.
  3. Gerber and Summary: For a test on ace-asking Gerber and a review of the chapter, go to Quiz 3 (p. 162). Try a, c, d-g.
Hands to Play, from BB3, Popular Conventions (230 p.)

Note that we have studied NT, major-suit, and minor-suit bidding, so please bid. However, if you reach a different contract than AG, please play her contract and opening lead. Consider playing the hands as “double dummy” so that everyone at the table can see the offense and defense unfold. If you finish the four hands early, please use the remaining time for dealt hands.

Deck Hands Declarer Dealer Bid Lead Hints
BB3 P. 128, #13 N N 6NT T♠ A
BB3 P. 130, #14 W E 6♥ J♠ B
BB3 P. 132, #15 E S 5♠ T C
BB3 P. 134, #16 S W 6 K♣ D
  • A: N=15 HCP, 0 LP, 0.5 DP. S=18 HCP, 0 LP, 0.5 DP. North (N) opens 1NT. South (S) supports quantitatively to 6NT. Lead is top of 5c♠ sequence. N has 10 QT, must drive out K♦. Making small NT slam nv. (+990).
  • B: W=19 HCP, 1 LP, 1 DP. E=13 HCP, 1 LP, 1 DP. East (E) opens 1♦. West (W) bids ♥ and E supports. E is a minimum. W bids Blackwood to find 1 Ace. With 1 Ace missing, W stops at a small slam. Lead is top of 5c♠ sequence. W has 11 QT, must drive out A. However, W has two losers, so begins with ♦ to discard a ♠ loser. Making a small major slam nv (+980).
  • C: E=13 HCP, 2 LP, 3 DP. W=19 HCP, 1 LP, 1 DP. West (W) opens a maximum with 1, is happy to hear E shift to 1♠. W shows their points with a double jump support of ♠. East bids Blackwood. West says one Ace, and E stops at 5♠. Lead is top of 5c♦ sequence. E has 9 QT, can develop four tricks by driving out the A. Opponents win their 2 Aces. Making 5♠ v (+900).
  • D: S=15 HCP, 3 LP, 3.5 DP. N=15 HCP, 0 LP, 0.5 DP. N opens 1NT. S jumps to Gerber. N reports 2 Aces, and S goes to 6♦. Lead is top of a 2c honor sequence. S has 8 QT and six slow tricks. S drives out the A♦. Making small minor slam v (+1,370).

_ _ _ _ _ _

1PVP: Partnership Valuation Points = HCP + Length Points (for Declarer) + Dummy Points (for Responder). Declarer’s PVP = their HCP + their Length Points. Responder’s PVP = their HCP + their Dummy Points. All points discussed in this paper are PVP unless we identify them as HCP.

Student Notes: (nb: Students may download the latest revision of AG BB3 Ch4 at

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