White fianchettoes their queen’s bishop right away, attacking e5 (and Black’s kingside) but leaving their own b4-pawn unguarded. White reckons that Black’s central pawn will be worth more than a flank pawn, which generally is the case. This is a relatively uncharted opening. Black can try:

• 2...Bxb4 which practically forces White to play 3. Bxe5 with an unclear position in practice, though computer analysis has shown this position to very slightly favour White.
• 2...d6 which protects black's pawn on e5, but removes the attack on b4.
• 2...d5 which takes full control of the center, but Black must be careful not to fall into the trap 3. Bxe5 Bxb4?? allowing 4. Bxg7 with a winning position for White (Black’s rook will meet its demise next move, with no compensation).
• 2...Nc6? is a bad move. After 3. b5!, White wins a pawn after the knight moves, with 4. Bxe5.

1. b4 e5 2. Bb2