This game was a GQA where I had the dream position from the start. My opponent played moves which I had seen before and were logical but I knew to be slightly inaccurate.
The first position above immediately removes us from the book. Nc6 blocks the standard c5 push Black tends to play in order to undermine the White’s central control. It also doesn’t allow Black to immediately play b5 hitting the Bishop on c4 after Bxc4.
Again, Re8 seems completely logical. It appears as Black is getting ready to push e5 and attack the center but are they ready? There are positional problems in addition to tactical problems with pushing e5. Black needs to shore up some things in the position and get their pieces more active before venturing forth.
It might not be apparent but Black is in dire straits after e5. As played in the game after 12. dxe5 Nxe5 13. Nxe5 Rxe5 14. Nf3 (with tempo on the rook) Black doesn’t have much to show in terms of long term strategy or tactical blows. The game continues with 14…Bg4?? a completely normal looking move which aims to pin the knight to the Queen while developing but it’s this move that loses the game.
There is a tactical shot here which wins the game on the spot. Black’s attempt was to pin the knight in order to remove the attack on the rook on e5. If I were to take immediately 15. Nxe5 Bxd1 and I would be down a Queen, however, notice 15. Qxd8+! (It captures the Queen on d8 with check forcing Black to recapture on their move.)…Rxd8 (I no longer have the Queen pinned to the knight) 16. Nxe5 and Black is down a full rook.
Every mistake Black made in this game was a seemingly decent move, most of them followed principles any player should know. Under certain contexts those principles can fail and shouldn’t be followed blindly. Many positions require calculation instead of acting on blind faith, though this was a blitz game not everything can be decided on by intuition.
The final position of the game. Black resigns as there isn’t much hope being down a rook and minor piece.