f4 vs b4 in this position?

Hello! I am new to chess.com forums.

    I recently played a game against a 1500 player (I'm 1200). Two turning points in the game. I've listed the first. At move 10, I played b4. The computer analysis suggested that my +0.5 went to -0.5 at that time. f4 was recommended.

    I am unsure why. Thank you for your consideration.

f4 pushes a pawn protected by a rook, gives white more space advantage, and can be used to attack later. b4 doesn’t do much. Also, g4 is the best recommendation of the engine (just saying).

Thanks! I'll keep f and g pawn pushes in mind for the future. I appreciate your help.

     I then pushed to a5 hoping to open up the b file. A weak line, I can see. He pushed his pawn to b5, and that closed off the left side of the board! Best regards.

Mike

Oops! I meant g4 rather than f4 in the original post. I had a brain freeze after seeing the computer analysis. Best regards.

Mike

#1
The normal move is 10 f4 but 10 g4 is good too, that is just a question of move order. The idea is then to push g5 to chase the defending Nf6 and then attack with Qh5.
10 b4 is generally bad: too weakening, and not useful. Pawn c2 becomes backward on the open c-file.

b4 significantly weakens white’s control of the squares c3 and c4, both of which can easily exploited by black due to the open c-file.

Thank you!

Mike