A rather tortuous route to a King's indian Attack: via a Pirc, then a Philidor.

It seems possible he figured that f2 was a vulnerable point. Seems a tad optimistic, but.

Let's be honest, it is beginner's mistake. It is not in either of the Gameknot opening databases, and for good reason. On this square the queen can easily be attacked, by say d3 or d4 followed by Bg5 or by Nb1-c3-d5. Also the queen takes away the f6 square from the knight at g8, which normally goes to f6.

Good: flexible thinking. One should always be alert in even the most familiar opening to nuances that indicate departures from the routine.

Yes I would have played this move too.

But I am not convinced by this move. It may be better to continue development with say 0-0 before starting on such adventures. Nd5 also looks good to me.

Creative, but this turns out badly after 8.Bg5 etc. Black really had to bite the bullet and play the obvious: 7...exd4 8.Bg5 Qg6 9.Bxd8 Qxe4ch! 10.Kd2 {else 10.Qe2 Qxe2 11.Qxe2 Bc4ch or 10.Kf1 Bc4ch} 10... Kxd8. Black will have picked up two pawns for the exchange, and still be in the fight. Note that, as good a move 7.d4 was in unleashing a dual threat, Black still had resources to contain the damage. Even so, let that be a lesson to him about the consequences of injudiciously bringing out the Queen too early.

I agree with Ion, but would add that after 11.Kc1 white would have a slight edge.

In view of what follows, probably he should have played it anyway, just to get a pawn back for the exchange, and to reduce White's resources in the centre.. Note that Black's ...d5 move has cut across the possibility of ...Bc5ch after an exchange on e2, or if the White King were to retire into f1.

White has a wide range of strong possibilities here. I quite like 10.exd5, which leads to exchanges favourable to White: 10.exd5 Qe4ch {There's not much Black can do about this. After 10...Bxd5 11.Nh4! Qe6 12.Bxd5 Qxd5 13.dxe5 and the Queens come off anyway} 11.Kf1 Qxd5 {not 11...Bxd5 12.Nh4!} 12.dxe5 and off come the Queens. The game will have arrived prematurely into the late middlegame, with White an Exchange plus Pawn to the good.

This won't even slow White down. You couldn't even call it a speed bump. 11...Bd7 at least carried a threat...

Interesting would have been 12...Bg4, as White could then have gone in for... a Queen sacrifice! Check it out 13.dxc6ch!! Bxd1 14.Rxd1ch Ke7 {14...Kc8 15.cxb7ch and 14...Ke8 15.Nc7ch both lead to Black's swift quietus}. White can choose between 15.c7 Qxc2 16.0-0 and the c-pawn soon promotes; or try for the King Hunt (though this requires care!) 15.Rd7ch Ke6 16.Nc7ch Kxe5 17.Rd5ch Kf6 18.Ne8ch Ke7 19.Re5ch Kd8 20 c7ch Kc8 21.Bh3ch f5 22.Rxf5 {22.Bxf5ch also wins} 22...Qxe8ch 23.Re5ch Kxc7 24.Rxe8 Nf6 Rc8ch and White has a winning endgame.