In this post, we consider the Budapest defense.
1. d2d4, g8f6.

2. c2c4, e7e5.

3. d4e5, f6g4.

4. c1f4, b8c6.

5. g1f3, f8b4+.

ATTENTION!!!
Avoid this trap for whites.
6. b1d2, d8e7.

7. a2a3, g4e5.

8. a3b4, e5d3 checkmate!

The Budapest Defense (or Budapest Gambit) is an aggressive, offbeat opening for blacks against 1. d2d4, starting with 1. d2d4 g8f6 2. c2c4 e7e5. Blacks sacrifice a pawn to disrupt whites center, gain rapid development, and create immediate traps. It is highly regarded as a dangerous weapon for club-level players.
It is a sharp, tactical chess opening that emerged in the late 19th century to challenge whites control, specifically aiming to disrupt typical Queen's Gambit structures. It gained prominence through Hungarian players around 1916–1918 and remains a dangerous surprise weapon.
For more info see [ 3-6].
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References:
1. https://www.dynpass.online/tools/chess/start.html
3. https://www.chesshistory.com/winter/extra/budapest.html
4. https://www.chess.com/article/view/the-budapest-gambit-revisited
5. https://www.youtube.com/watch?v=tNRm5qLcJRQ
6. https://www.youtube.com/watch?v=8mJEqdEa6-w