The Gerber convention was devised by Mr. John Gerber in 1938. This convention is sometimes referred to as the Four Clubs Blackwood. However, the concept was devised independently by Dr. William Konigsberger and Mr. Wim Nye, and was also published by them in Europe in 1936.
The Gerber convention uses the bid of 4 Clubs to ask partner how many Aces he holds, and subsequently how many Kings.
According to the concept, as soon as a suit or No Trump has been agree upon, preferably No Trump, the responder will bid 4 Clubs to ask for Aces. In No Trump auctions, it is almost always the responder who will ask for Aces and Kings, since the opener has conclusively limited his holdings. The Gerber convention was devised in order to ask for Aces and Kings One Level lower than with the Blackwood convention. In this manner, the two partners can stop the auction, if it proves necessary, on a Lower Level.
The responses of the opener to a 4 Club bid by his partner, who is asking for Aces are:
shows no Ace or Four Aces
shows One Ace
shows Two Aces
shows Three Aces
The responses of the opener to a 5 Club bid by his partner, who is asking for Kings are:
shows no King or Four Kings
shows One King
shows Two Kings
shows Three Kings
SLIDING GERBER or ROLLING GERBER
Side Note: In the original concept of the Gerber convention, the auction was a little different. This is known as Rolling Gerber or Sliding Gerber. Some partnerships still apply this method.
The responses of the opener to a 4 Club bid by his partner, after agreeing that No Trump is the Contract, and who is asking for Aces are:
shows no Ace
shows One Ace
shows Two Aces
shows Three Aces
shows Four Aces
The responses of the opener to a 4 Club bid by his partner, after agreeing that a Spade/Heart/Diamond/Club Contract is the contract, and who is asking for Aces are:
Agreed Suit is Hearts Responder Opener Responder asks for Aces: 4 4 One Ace Responder asks for Kings
by bidding the next higher
ranking suit: 4
4 NT No King 5 One King 5 Two Kings 5 Three Kings
5 Four Kings Responder may not bid
the agreed Trump suit
to ask for Kings.
The Rolling Gerber, or Sliding Gerber, has proven to be ineffective in some auctions due to the ambiguity of the bidding, especially if the contract is Clubs. The difficulty in distinguishing between a conventional and a natural 4 Clubs bid in such cases caused many bridge players to adopt the more effective method mentioned above. Another factor is the procedure with a void, and still another factor is an intervening call. The Rolling Gerber, or Sliding Gerber, did not provide for such instances.
Bridge partnerships have agreed to use the Gerber convention in Suit Contracts. The following two auctions should clarify this partnership agreement.
The 4 Clubs bid by the opener is the Gerber convention.
The 4 Clubs bid by the responder is the Gerber convention.
It must be noted, however, that most bridge partnerships have decided that they are not willing to surrender the 4 Clubs bid as a natural bid or as a cuebid. These bridge partnerships have decided to use the Gerber convention only after a No Trump opening.
Using the Gerber convention after a 2 No Trump Opening can cause partnerships some amount of ambiguity. Using the Gerber convention after a 3 No Trump Opening can cause some partnerships several headaches. Even using the Gerber convention after a Strong Artificial Two Club Opening with a Two or Three No Trump Rebid could cause the partnership to suffer. The following example should illustrate these difficulties, and possible ambiguities.
Opener Responder 2 NT
9 K97 Q104 KJ10865
It is evident that a possible slam in a Club contract is in the making, but how to get there. A bid by the responder of 3 Clubs is normally used as the Stayman convention, asking for a 4-card Major suit. Some partnerships have decided to use the immediate Jump to 4 Clubs as the Gerber convention. Still other partnerships have agreed to use the 3 Clubs bid, followed by a 4 Clubs rebid as the Gerber convention. Whatever the partnership agreement may be, these partnerships have no way to bid Clubs naturally.
Assuming the same example as above:
If the responder bids 4 Clubs, the opener will have some difficulty in deciding whether this bid is natural, or the introduction of the Gerber convention. Several partnerships have solved this problem by reserving the 4 Clubs bid by the responder as the Stayman convention, and a 4 Diamonds bid by the responder as the introduction of the Gerber convention. The meaning of these two bids can, however, be reversed by other partnerships. It seems more logical to use the 4 Diamonds bid as the Stayman convention, reserving the 4 Clubs for the Gerber convention. There are also some partnerships who employ 4 Clubs as the Stayman convention, and 5 Clubs as the Gerber convention, thereby taking the opener one Level higher than Mr. John Gerber intended.
Opener Responder 3 NT
9 K97 Q104 KJ10865
However you wish to employ the Gerber convention, and whether or not you wish to employ the Gerber convention, or even if you wish to employ the Rolling or Sliding Gerber convention, the decision should be made known to your opponents on the Convention Card. However the decision falls, please make it a part of your written Partnership Agreement. Our suggestion is that you and your partner deal out a few hands where the Gerber convention could be employed by Suit Contracts, examine the method and possible ambiguities, and discover whether or not you and your partner feel comfortable with this convention.
If you wish to include this feature, or any other feature, of the game of bridge in your partnership agreement, then please make certain that the concept is understood by both partners. Be aware whether or not the feature is alertable or not and whether an announcement should or must be made. Check with the governing body and/or the bridge district and/or the bridge unit prior to the game to establish the guidelines applied. Please include the particular feature on your convention card in order that your opponents are also aware of this feature during the bidding process, since this information must be made known to them according to the Laws of Duplicate Contract Bridge. We do not always include the procedure regarding Alerts and/or Announcements, since these regulations are changed and revised during time by the governing body. It is our intention only to present the information as concisely and as accurately as possible.