1 e4 c5 2 Nc3 e6 3 f4 a6
GM Bui responded with a rare but solid continuation that was played in Kamsky vs Anand in Groningen 1993 and in Aronian vs Ivanchuk in Monte Carlo 2006.
Often played here is 3... Nc6 as in Anand vs Kasparov in New York 1994 and Short vs Topalov in Dos Hermanas 1997.
4 Nf3 Nc6 5 g3
Pau played a move which according to chessgames.com statistics favors the Black side; only 20% wins for White against 50% for Black. But Pau is just in high school and does not have a Statistics subject.
5... d5 6 d3 Be7 7 Bg2 Nf6 8 O-O
One of the most important guidelines in chess is to protect your K from harm. Watson in Mastering the Chess Openings
Castling was played in Hickl vs Ehlvest in Zagreb IZT 1987, Short vs Polgar in Najdorf Memorial 2001, and Aronian vs Ivanchuk in Monte Carlo 2006.
9 Ne5 Bb7 10 Nxc6 Bxc6 11 e5 Nd7