4th Chess Festival Montebelluna - A

[#] There is a saying that you can draw an arrow with the pawn chain and see where it point towards - and that you will get the answer to which side you should play on. Black's pawn chain point towards the queenside and while White's two pawn chains point in both directions, since Black has more space on the queenside, White will play on the side where he has more space - the kingside thanks to the e5-pawn. Now, Black played a big mistake: