Chess Opening Theory/1. e4/1...Nf6/2. e5/2...Nd5

Black's knight, under attack, moves to a safer square, but may soon move again.

3. d4 is the most intuitive move. This reinforces White's advanced but weak pawn, and opens lines for White to develop. After 3...d6, chipping away at the end of White's pawn chain, White has the choice either to seize as much space as possible, 4. c4 Nb6 then 5. f4 dxe5 6. fxe5 Nc6, the four pawn attack, or 5. exd6 exd6, the exchange variation; or to focus on not falling behind in development, 4. Nf3 Bg4 5. Be2 e6 6. O-O Be7 7. c4 Nb6 8. Nc3 O-O 9. Be3 Nc6.

3. c4, the two pawns attack keeps attacking the knight. After 3...Nb6, 4. d4 d6 transposes or 4. c5 is the Lasker variation.

3. Nc3, the Sämisch attack, is an option to avoid the sharpest lines of the Alekhine. After 3...Nxc3 4. dxc3 White can accelerate their development in compensation for doubled pawns, or 4. bxc3 increases control of d4.

3. b3 is the Welling variation.

1. e4 Nf6 2. e5 Nd5

Wikipedia has related information at Alekhine's Defence.

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