The Budapest Gambit (1.d4 Nf6 2.c4 e5!?) is a swashbuckling gambit where Black assumes the initiative from the word go and will most often recover his pawn with a well developed game.
FOXY OPENINGS - VOLUME 15 - Budapest Gambit
In part 2 of the series IM Valeri Lilov examines a sharp repertoire for both black and white. A complete system you can employ in your own games! Valeri's take on theory is both aggressive and based on sound strategic principles. He examines White e 4 and one good line of play for all of Black's possible responses with the Budapest Gambit. Also, how White can respond to the Budapest Gambit and how to respond to deviations on most of the various openings including with the Grand Prix attack.
An Opening Repertoire for the Attacking Player Lectures 5-9 - Chess Lecture - Volume 81
by GM Eugene Perelshteyn and FM Dennis Monokroussos
The Budapest Gambit (or Budapest Defense) begins with the moves: 1.d4 Nf6 2. C4 e5 The Budapest Gambit contains several specific strategic themes. In numerous variations the move c4–c5 allows White to gain space and to open prospects for his light-square bishop. For Black, the check Bf8–b4+ often allows rapid development.Once used by Vidmar to beat Rubinstein convincingly in just 24 moves.
Studies in: The Budapest Gambit - Chess Lecture - Volume 131
The Budapest Fajarowicz Gambit
The Fajarowicz Gambit suffers from a dubious reputation, but as FIDE Senior Trainer and IM Andrew Martin shows, that assessment is not justified at all. If Black shows common sense and a knowledge of the variations, then he may well get a very good or even winning position right out of the opening. The unorthodox Fajarowicz Gambit is perfect for all those who enjoy chess and wish to explore the tactical richness of our noble game.
Foxy Openings - Volume 163 - Crushing Opening Traps