minh

Possible continuations: Nxd4 exd4 Rg3 dxc3 or just Qd2 dxe3.

Everything by white makes perfect sense until 5.Bd3?

Why would you want to block your own development?

Also, the position after 4...a6 is already unusual, and completely different from the almost identical position arrived at through the spanish opening, except that here the knights at c3 and f6 have already developed.

This means a lot. For example, white can even play:

5.Bxc6 dxc6 6.Nxe5!? in the spanish (without the c3 and f6 knights), black can play here either Qg4 (oops, f6 knight prevents that:) or Qd4 (woops, here Nf3 and the pawn is already guarded by the c3 knight:) to win the pawn back.

So black will have to play something like 6...Nxe4 7.Nxe4 Qd5, but the queen is very exposed here: 8.0-0 Qxe5 9.d4 Qd5 10.Re1 - superb position for white.

There's also inconsistency in white's play: why would you play Bd3 if you just move it back to c4 the very next move without it gaining anything from that manuever? just play Bc4 to begin with, if that was what you wanted.

by the time black played 13...d5, the position is already completely equal, and you must take care of the fork (Re1).

In the game, black could have tried to push for an advantage, using his slightly better piece placement and slightly better development with 11...d5.

Black and white boards are very ugly. It's too stark. It's no wonder they don't use them in real life.