Jgamazo: Morphy formulated the principles of classical play from watching his father and uncle play, and his own games against them. No books, computers, or great competion. 1.Control the center, 2. Develope all your pieces, 3. Castle your king early 4.Open lines for your bishops/ open files for your rooks/ create advanced outposts for your knights. 5.Attack.
In this game his opponent ignores the second and third, and is lost.
Sicre's first 6 moves are with pawns. Morphy has castled and has a bishop and knight in the field and will shortly have an open file for his rooks.
4. ... h6? to prevent the knight going to g5, if you want a losing move here it is. Better was Be7 to help the king castle, or Nc6 developes the knight and protects the d pawn, or the aggressive Bg4 to prevent the knight taking d4.
7. ... Qc7? Still neglecting development, why not 7. ... Be6? 8.Bxe6 fxe6 9.Qxe6 Qe7 I doubt Morphy would take the Queen here, He likes to save her for the attack, and Black is back in the game.
8. ... g5?? another pawn move! Prepareing for Bg7? So Morphy put a bishop on e3 heading for c5 to cover the abandoned diagonal.
10. ... Bxc3? Bad, yes, it loses a rook, but nothing was going to save this game.
12.e5 opens lines straight to the uncastled king.
14. ... Qd8 all the pieces are on the back rank, except the doomed rook. After this Morphy prepares to use f6 to lauch his final assault.
18. ... Nd7 Black realizes f6 is a route to the king and prepares to defend f8.
21.Bc5 Black resignes. The threat was 22.Nf6+ Nxf6 23.Bxf6 Qc8 ( 23. ... Qxf6 24.Qxf6 Ng6 25.Rxe6+ fxe6 26.Qxg6+ Kd7 27.Re1 Kc8 Qf7 and mate next.) 24.Rxe6+! fxe6 25.Qe7#