What an opening.

After, I follow e4. When black tries to protect his c4 pawn, maybe by moving his pawn to b5, he completely opens his right flank just to protect that centre pawn. I've won a LOT of games by early checkmates like this.

It allows the early fianchetto of Black's queen bishop.

Landau - Reshevsky 1937 went

1. d4 d5  2. c4 dc  3. Nf3 Nf6  4. e3 a6  5. Bc4 e6  6. 0-0 c5 7. Qe2 b5  8. Bd3 cd  9. ed Bb7  10. a4 b4  11. Nbd2

Reshevsky comments that the white knight quickly gets to c4 and points out that this line is better for Black if White's knight is on c3 -for example if White plays 6. Nc3  instead of 6. 0-0.

e3 is a good move too

nek26, you waste the opportunity of the free pawn while giving check, as the canadien with the numbers said.

Qd4+ then Qxc4 to gain material.

Can anyone help explain to me why Nc3 is a bad move here?