Because When you face the Open Games (Ruy Lopez, Italian, Scotch), you cannot rely on system-style moves (like in the London System or the King’s Indian Defense). You must know concrete theory.

This is why the Plichta-s 1 e4 e5 7z file is famous on file-sharing networks: it is incredibly small to download but massive in content.

Once you extract the PGN, go to the Two Knights Defense line (1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6). Verify that Plichta gives a solid line against 4.Ng5 (the Fried Liver Attack) if you are playing White, or the 4.d5 Traxler Counter-Attack if playing Black. That single chapter is worth the download alone.

Start your extraction, load your engine, and never lose to a cheap 1.e4 e5 trap again.