Chess Opening Theory/1. e4/1...Nf6/2. Nc3/2...d5/3. e5

= Alekhine's Defence =

3. e5
From here, black has 2 main choices:

3... Nfd7
3... Nfd7 is completely sound option and generally transposes into the French Defense, Steinitz Variation mainline after 4. f4 e6 5. Nf3 c5 6. d4 Nc6. This is an interesting (and occasionally sharp) position that would be a good idea for black if they want a sharp game, which is likely what was intended when playing the Alekhine. However, there is another way to reach a sharp position, but only if white agrees to it.

3... d4
3... d4 is another sound option, but is quite drawish because of the line 4. exf6 dxc3 5. fxg7 cxd2+ (not 5... cxb2?? 6. gxh8=Q! and bxa1=Q is met with Qxa1, where white is simply ahead a queen) 6. Qxd2 Qxd2+ 7. Bxd2 Bxg7, where a pair of knights and queens have been traded. This position is notoriously drawish, with a 74% draw rate and just a 19% winrate for white. However, white can keep the position interesting with 5. d4!? cxb2 6. fxg7 bxa1=Q 7. gxh8=Q with a very unclear and sharp position with four queens on the board! Yes, four queens - and it's not even move 8.

Theory table
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 * '1.e4 Nf6 2.Nc3 d5 3.e5'