Position from my game. Why is b4 the best move here?


5. ...Qxd6 is a mistake. Black should capture and win by trade the pawn on f3 first, then let White exchange the queens.
Nxf3+ Bxf3 Bxf3 Qxc7+ Kxc7 Rf1? might win the piece. I dunno

Here's another line I want to explore with you:
I didn't see Qf5. oops. What about 4...Bh6?

Black has Ne4.
White's c3 knight takes it?
Yeah, and then Bd4+ Nf2 Re2 settles things to a draw. This position seems so aggressive for Black yet it's completely busted. White also can't do anything.
Here's the position after these moves:
hows this a draw? just push the h-pawn.