Chess Opening Theory/1. e4/1...Nf6/2. e5/2...Nd5/3. d4/3...d6/4. c4

= Alekhine's Defence = White grabs even more space and wins a tempo. Black's knight is under attack again. The only reasonable move is /4...Nb6/.

Theory table
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1.e4 Nf6 2.e5 Nd5 3.d4 d6 4.c4