Chess Opening Theory/1. e4/1...Nf6/2. e5/2...Nd5/3. d4/3...d6/4. Nf3/4...Bg4

= Alekhine's Defence =

Black has reduced White's control over the center. Black usually gives up his bishop for the knight and doubled pawns on the f-file.

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