White has given up his king's pawn, in hopes of an aggressive game. Since there is no way White can win a pawn back immediately, he can expect this set-up most times he plays the Blackmar-Diemar Gambit. The best move for White would be Nc3, putting pressure on the e4-pawn and preparing the move f3, as 3. f3 is well met by 3...e5!, with an edge for Black. One example: 4. dxe5 (other moves are even worse, for example 4. fxe4 Qh4+ and Qxe4 with an extra pawn and an attack, or d5 Nf6 c4 c6 when d5 will soon fall) Qxd1+ Kxd1 Nc6 fxe4 (f4 Bg4+ Ne2 O-O-O+ with a winning attack) Nxe5 with an obvious advantage. Black normally plays 3...Nf6, though 3...f5 and 3...Bf5 are interesting ways to avoid mainline theory. Now, if f3 e5?, dxe5 gains a tempo on the knight. Sometimes Bc4 is played, to hopefully trap Black quickly with a variation of Scholar's Mate.

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1. d4 d5 2. e4 dxe4

Wikipedia has related information at Blackmar-Diemer Gambit.

• Kasparov, Garry, & Keene, Raymond 1989 Batsford chess openings 2. ISBN 0-8050-3409-9.