When it appears from the bidding that you and your partner are very strong together, you think of examining a slam contract.
The course of the first bids determines the later method to be applied. We distinguish two bidding courses:

• the opener possesses more than common opening strength, or the responder is very strong
  the auction is opened in NT, i.e. as seen from the opener in one of the next series:
  • 1§, pass, 1¨, ?,1NT
  • 1§, pass, 1 ©/ª, ?, 2NT
  • 1§, pass, 1NT, ............
  • 1¨, pass, 3NT, ............
  • 1NT, ?, ?, ?
  • 2§, ?, ?, ?, 2/3NT
  • 2¨, ?, ?, ?, 2/3NT
• the auction has been opened by a bid in a suit i.e.
  • all other bidding series with slam potency
    • when the opener shows strength by bidding reverse and the partner possesses a nice fitting hand
    • when the responder shows strength and nice fitting distribution

Experience learns that in the first case usually the bidding ends up in a NT contract. Is very hard to exchange controls in NT bidding courses. For that reason in MAF, Gerber is enabled. From the table, which comes soon, you may conclude that this gives a lot more useful information than Blackwood would have done.
It is allowed to examine your hands first with Stayman or Jacoby, before applying Gerber. As long as you don't bid on the 4-level, Gerber counts always. When the bidding goes beyond that border Blackwood counts instead.

The bidding series of the second case appear often to end up in suit contracts. After establishing the trump suit (with strong hands), the exchange of controls is started, and subsequently Blackwood might be applied to ask for Aces and Kings.

The description of the typical agreements is given in the next diagram.

Meaning of RESPONSES to the "Number of Aces question" GERBER 4 § The final contract will be in NT BLACKWOOD 4 N.T. trump suit has been established trump suit not yet established 4¨ 0 or 3 Aces 5§ 0 or 3 Aces 5§ 0 or 3 Aces 4© 1 or 4 Aces 5¨ 1 or 4 Aces 5¨ 1 or 4 Aces 4ª 2 Aces 5© 2 Aces 5© 2 Aces 4NT 2 Aces + 1 King 5ª 2 Aces + trump King and/or Queen 5ª 2 Aces + 1 King 5§ 2 Aces + 1 King + 5-card 5NT 2 Aces + void 5NT 2 Aces + 2 Kings 5¨ 2 Aces + 2 Kings 6§ 2 Aces + trump King and/or Queen + void 6§ 2 Aces + 2 Kings + 5-card 5© 2 Aces + 3 Kings     5ª 2 Aces + 3 Kings + 5-card 5NT 2 Aces + 3 Kings + 5-card 6§ 2 Aces + 4 Kings 6¨ 2 Aces + 4 Kings + 5-card The cheapest rebid by the 4§ bidder after a response of 4¨ or 4©, is asking for Kings and beyond 4© it is asking for Queens If the rebid of the 4NT caller is in the trump suit or in NT, the bid is always final. All rebids in potential trump suits or in NT are always final bids.

It is clear that before asking for the number of Aces, you should commonly know, which suit is going to be the trump suit. In MAF there are many ways to establish the trump suit:

• if the player who establishes the suit is weak and does a preemptive call, or when the hands are to weak to achieve a game contract quickly.
  • by a solitary action of one of the players
    • simply by passing on your partners bid
    • by applying the Lebensohl through bidding a suit along the by pass
    • sometimes by a 3 in a suit opening bid (the 8-suiter, de lhoSSohl and the Simple Soul Sohl)
    • by bidding the same suit for the third time
    • by showing a weak 1-suiter after a multi way opening bid or after a Sohl response
  • by supporting your partner's suit (the suit bid or the suit pointed to by bidding)
    • by executing a support redouble when your partner did an overcall or response
  • by choosing a suit out of the alternatives your partner offers, through next conventional bids.
    • through application of the Muiderberg convention
    • the Ghestem
    • the 2NT opening bid
    • the WHIMS convention or the 2NT response to one of the minor suit opening bids
• in case of strong hands when a game contract should be bid at least
  • by a solitary action of one of the players
    • in all situations, where the opener or responder jumps to a game contract
    • through application of the Lebensohl convention and bidding directly a suit on the 4-level
    • by opening strong in a suit, along one of 2-level minor suit opening bids, and repeating that suit on your next turn, unless your partner's negative response
  • by supporting your partner's suit (the suit bid or the suit pointed to by bidding)
    • by supporting your partner if he did a strong opening bid along one of the 2-level minor suit opening bids. Responding 3§ to a strong major, or 3 in the unbid minor establishes the strong suit as trump suit. When bidding anything else, except repeating the strong suit, no trump suit has been established yet.
    • by applying the Jacoby-2NT convention the opening suit is established as trump suit; this also counts for the Truscott variant, which also could have been called Jumping Jacott Sohl
    • by giving a splinter response to a major suit opening bid; this establishes the the opening suit as trump suit
    • by refusing to accept a transfer bid (Jacoby); the refused suit will be trump suit and the suit, called instead, indicates a control in the cheapest suit.
    • by bidding the opponent's suit after an overcall on partner's opening bid (cue bid); this shows a void/singleton in the overcall suit; the opening suit is established as trump suit
    • by bidding the opponent's suit after an overcall on partner's response (cue bid); this shows a void/singleton in the overcall suit; the suit of the response is established as trump suit
    • sometimes through a 3 in a suit opening bid (strong 5,5 distribution)
  • by choosing a suit out of the alternatives your partner offers, through next conventional bids.
    • the superMAF overcall after a preemptive opening bid
    • de weevandedree after the 2§ opening en de 2¨opening bids
    • by the application of the MaD+++ convention after an opening in diamonds.
    • through applying the SHiD+++ convention after a club opening bid

Sometimes it happens that during the control bidding one of the the players is convinced already, that small slam certainly can be made. This player should then consider seriously to call grand slam. To examine this possibility he could decide to skip the Blackwood 4NT bid, and do the 5NT grand slam convention instead.
This convention can only be applied to establish grand slams in suits. Next table shows how the 5NT convention works.

To examine a N.T. grand slam in a sound way, the modified Gerber convention should be used. Gerber was explained in the table before.

Meaning of the FORCED RESPONSES to a bid of 5 N.T. after having established the trump suit and after having executed a chain of control bidding exchanges and: without calling 4NT before, or by the 4NT caller after hearing 2 or more Aces; never show trump Ace twice response to 5NT intended TRUMP SUIT § ¨ © ª 6§ sign off no A/K no A/K no A/K 6¨ - A/K A/K no A/H but L/Q 6© - - A/K + L A/K 6ª - - - A/K+L 7 A/K+K/Q A/K+K/Q A/K+K/Q A/K+K/Q Explanation symbols:       A/K = Ace or King ,  L/Q = Length or Queen   in the trump suit.          = any trump suit

It is not necessary to jump to 5NT to make this bid conventional. If the exchanging of controls went on beyond the 4NT level, the only fly way left is a 5 - or 6-level bid in the established trump suit. When 4NT has been called, commonly the the conventional meaning of 5NT doesn't count any more, unless 2 or more aces have been shown, but in that case an eventual aces in trumps cannot be declared a second time after the 5NT. In other cases 5NT is a final bid.

The diagram shows that the response never exceeds the 6 level. The nearer the response approaches it, the stronger is the support. With the strongest support imaginable, the responder should always call the grand slam.

When you want to see bridge games, in which the principles, described above, are applied, you should click for examples, and make your choice when you're arrived there.