Chess Opening Theory/1. e4/1...Nf6/2. e5/2...Nd5/3. d4/3...d6/4. c4/4...Nb6/5. f4/5...dxe5/6. fxe5

The white center is now very strong. Black has two main options to counter it.
 * /6...Nc6/ attacks the d4 pawn. This pawn cannot be pushed as the e pawn would be left en prise.
 * /6...c5/ is far riskier. After 7. d5, Black can be strangled. This game is going to be very tactical.

/6...Bf5/ is also possible & keeps the option of ...c5 before ...Nc6, but it tends to transpose into 6...Nc6.

Theory table
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'1.e4 Nf6 2.e5 Nd5 3.d4 d6 4. c4 Nb6 5. f4 dxe5 6. fxe5'