Very Simple Chess Question

Our game has gone like this:

  1. nf3 nf6
  2. d4 d5
  3. h3

What is the purpose of h3 in this situation? I cant figure it out. I am black.

Largely to keep your Bishop off g4, I guess, so you can’t trade off White’s Knight and possibly spoil his pawns. But there would have been many better moves.

And to prevent the pin on the knight when the e-pawn moves. It also serves as luft, preventing back rank problems later in the game after castling. Generally it does waste a tempo this early in the game as the pin is easily dealt with and you can provide luft a number of ways later on. Punish him by playing centrally.