Chess Opening Theory/1. d4/1...d5/2. c4/2...dxc4/3. e4/3...e5

This is the most common and ambitious reply by Black. This move attacks White's centre and opens up the dark-squared bishop.

There is only one move that preserves White's advantage, that being 4. Nf3, attacking e5 and defending d4.

4. Bxc4? doesn't work due to 4...Qxd4! 5. Qxd4 exd4 6. Nf3 c5 ⩱ and Black is able to build a fairly stable centre.

4. dxe5? also does not work due to 4...Qxd1!, forcing a trade of queens with Kxd1, and although material is even, White is exposed in the center and loses castling rights.

The first occurence of this variation is in 1834 in a game between Alexander McDonell and Louis de La Bourdonnais.^[1] White continued with 4. d5, which is not seen nowadays because it overextends White's centre which Black can easily undermine with moves like ...c6 and ...Bb4.

1. d4 d5 2. c4 dxc4 3. e4 e5

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