The situation after 7.♘e5 shows how black has neglected his own development for the sake of an apparently magnificent pawn center. This doesn't pass unpunished - one small tactical slip (the passive-looking 8. .. ♔f8 was the only way to avoid irreversible mayhem) and white can deliver a winning combo: 9.♕h5+ and 11.♘xf5! after which black's position is mortally struck (2 pawns down, chaotic development).

Black then takes the hanging queen, (maybe even on purpose since it was corr?) kindly allowing the coup de grâce: a pretty mate in one that is at least much more pleasing to the eye than a pointless agonizing defense like 11... Qb6 that after a few N-checks would have quickly led to the decimation of black's forces on the k-side.

I think this interesting opening (meaning moves 1-3) deserves a few words : it looks playable enough and gives white good practical chances to launch a deadly attack if black focuses too much on establishing a mighty pawn center.

D D Van Geet vs Versnel, 1950.
YOU ARE PLAYING THE ROLE OF VAN GEET.
Your score: 28 (par = 23)

More usual than 3.a3 is 3.e4 which leads to a normal variation of the Dunst opening after 3...d5 and 4.Nce2 but black can play h5 after the knight gets to g3, giving him the advantage.

Odd to think such an error allowing mate on the move should be made in a correspondence game where you have a day or two make a move. Though once in an international snail mail international tournament my opponent resigned against me is a won position! He saw only my threats without looking at what he could do.

Here Black's position prior to grabbing the Queen is pretty grim. Maybe he was just saving stamp money or, living up to his name, spent 5 seconds looking at each move before sending a reply. 'Versnel' is Dutch for 'Speed up'.