Blackmar–Diemer Gambit

The Blackmar–Diemer Gambit is a chess opening characterized by the moves: 1. d4 d5 2. e4 dxe4 3. Nc3

White intends to follow up with f2–f3, usually on the fourth move. White obtains a move and a half-open f-file in return for a pawn and as with most gambits, White aims to achieve rapid development and active posting of his pieces in order to rapidly build up an attack at the cost of the gambit pawn. It is one of the very few gambits available to White after 1.d4.

The Blackmar–Diemer gambit arose as a development of the earlier Blackmar gambit, named after Armand Blackmar, a relatively little-known New Orleans player of the late 19th century who popularized its characteristic moves (1.d4 d5 2.e4 dxe4 3.f3) and was the first player to publish analysis on the opening in the chess literature. The popularity of the original Blackmar gambit, however, was short-lived, as it was basically unsound, allowing Black to secure a superior position after White’s immediate 3.f3 with 3…e5!. In 1889, Ignatz von Popiel came up with the idea of 3.Nc3, though his main idea was to meet 3…Nf6 with 4.Bg5 (rather than the more usual 4.f3) and provided analysis of the Lemberger Counter-Gambit (3.Nc3 e5).

The evolved, modern form of this gambit owes much to the German master Emil Josef Diemer (1908–90), who popularized the continuation 3.Nc3 Nf6 and then 4.f3 (when 4…e5? is ineffective as 5.dxe5 hits Black’s knight and after 5…Qxd1+ 6.Kxd1 the knight has to retreat to d7 or g8). The position resulting after 3… Nf6 4.f3 reflects the main line of the gambit accepted, although other Black responses on move three are possible. After many years of analysis, Diemer wrote a book on the opening in the late 1950s, titled Vom Ersten Zug An Auf Matt! (Toward Mate From The First Move!), with most of the published analysis devoted to the Ryder gambit (and associated Halosar Trap), a double-pawn sacrifice characterized by the moves 4…exf3 5.Qxf3.

This gambit is considered an aggressive opening, but its soundness continues to be the subject of much debate both on and off the chessboard. The ChessOK Opening Tree Mode lists the Blackmar–Diemer as scoring 49% wins for White, 34% wins for Black and 17% draws. Dismissed by many masters on the one hand and embraced enthusiastically by many amateurs on the other, many consider that Black has good chances of defending successfully and converting the extra pawn in the endgame, while theory suggests that Black has many ways to equalize. As a result, this opening is rarely seen in top-level play, but enjoys a certain popularity among club players.

Some titled players, including International Master Gary Lane, consider the opening to be suitable at the club level and for young and improving players. In one of his Keybooks, the Rev Tim Sawyer said, “Stop playing for the endgame, play to end the game! Be a winner. Play the Blackmar–Diemer gambit!” On the other hand, Sam Collins (in his book Understanding the Chess Openings) noted the tendency for some Blackmar–Diemer fanatics to try to get the opening in every game, thus limiting their chess experience and concluded, “Nobody who plays good chess plays this line and nobody who plays good chess ever will.”

Other dismissive quotes include “playing the Blackmar–Diemer gambit is like shopping for a tombstone” (Andrew Martin) and “To convince an adherent of the BDG that it is unsound, is like trying to convince a child that there is no Santa Claus.” (Kevin Denny). As a result of the intense controversy surrounding the opening, much of the literature on the opening is lacking in objectivity.