White refrains from castling, leaving Black guessing which side he will choose and giving Black no clear target.

There is nothing to be gained by exchanging on e5. The Black knight is heading for d6, and from there to e4 or c4.

This does not really improve White's position, but the knight could have been booted away by . . . f6 anyway.

Preparing to advance the f2 pawn; White's gathering attack is looking menacing. Black must get some sort of counter-attack going very quickly, or risk being bowled over.

Testing the waters, to see whether White will trade.

At last, White commits himself; Black now has a stationary target.

The initial target is a3.

Both sides are attacking aggressively. Generally speaking: a) whoever strikes first will have the better prospects of success; and b) it is harder to hold the queen-side than the king-side because there is more territory to defend. White must be on guard against a piece sacrifice on a3.

Double defending a3; however, a queen is too precious to be defending pawns. Instead, the knight should have gone to b1 to hold a3.

This loses a pawn directly, but also removes one of Black's best attackers.