What is blackmar-diemer gambit?

The Blackmar-Diemer Gambit is a chess opening that begins with the moves 1.d4 d5 2.e4. It is also known as the BDG, and it is named after its inventors, Armand Blackmar and Emil Diemer. The gambit aims to immediately gain control of the center of the board, with white sacrificing a pawn in the process.

The Blackmar-Diemer Gambit is considered to be an aggressive opening and is not commonly played at higher levels of chess, as it is often met with solid defenses by black that can lead to a disadvantage for white if not played accurately.

However, the gambit can be effective in over-the-board or casual play, as it can often catch opponents off guard and lead to a quick attack. It is also a popular choice among amateur chess players who enjoy sharp, tactical games.

Some of the common black responses to the Blackmar-Diemer Gambit include accepting the gambit with 2...dxe4, declining with 2...e6 or 2...d6, or playing a transpositional move such as 2...Nf6 which can lead to a variety of different pawn structures.

Overall, the Blackmar-Diemer Gambit is a fun and aggressive opening that can lead to exciting games, but it must be played with precision and careful calculation to avoid falling behind in development or material.