Bishop's Gambit, Bryan Countergambit

The Bryan Countergambit, 4...b5, gives back a pawn to lure White's bishop off its post on c4 and to open a route for Black's light-squared bishop. Kieseritzky studied it in depth, and his name is sometimes attached to it. Most players now regard it as unsound. After taking the pawn, the bishop stands well on b5, while the c8-bishop finds no useful diagonal, so Black returns material without gaining much for it.