Breyer was a leading pioneer of the
hypermodern school of chess theory, which favoured controlling the with pressure from the . He was a friend of Richard Réti and an inspiration to other players. He is most notably recognised for the
Breyer Variation in the
Ruy Lopez, which involves Black re-routing his to d7 for increased flexibility (1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.0-0 Be7 6.Re1 b5 7.Bb3 0-0 8.c3 d6 9.h3 Nb8 10.d4 Nbd7; see diagram). This line became fashionable in the 1960s, and a favourite of ex-world champion
Boris Spassky. He is also recognised for the Breyer Variation of the
Vienna Gambit (1.e4 e5 2.Nc3 Nf6 3.f4 d5 4.fxe5 Nxe4 5.Nf3 Be7), as well as the Breyer Gambit (1.e4 e5 2.f4 exf4 3.Qf3), a variation of the
King's Gambit. He was an early adopter of the
Slav Defense (1.d4 d5 2.c4 c6) at a time when the
Queen's Gambit Declined (2...e6) was Black's most common response to the
Queen's Gambit, and is credited with the Breyer Variation of the Slav (1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nbd2). ==Notable games==