aka. Budapest Counter-Gambit

Board Position
One of the rarer Queen's Pawn side-defences, Black's aggressive king's pawn counter-gambit (move 2b, left) is sometimes tried by combative players hoping to catch an opponent off-balance. Board Position
Although perhaps the soundest of the queen's pawn game "gambit gambles" (M.C.O, Griffith & White), it can nevertheless tend to be inferior (favouring White, with less draws than average) if White meets the gambit correctly.
White accepts the gambit and then, with careful play, tends to gain a lasting positional advantage after castling in move 8wb (right). One example variation demonstrates a smothered mate however.
Begin or Clear or Groups or see: 1 d4 Nf6 2 c4 e5 for lines: 3 dxe5 to (Normal V.) 3..Ng4
To: (Adler V:) 4 Nf3 Bc5 5 e3 Nc6 6 Be2 0-0 7 0-0 Re1 8 Nc3 Ngxe5 9 Nxe5 Nxe5 10 b3 a5
(Rubin. V:) 4 Bf4 Nc6 5 Nf3 Bb4+ 6 Nbd2 Qe7 7 a3 Ngxe5 8 Nxe5 Nxe5 9 e3 Bxd2+ 10 Qxd2 d6