Carlsen is born on November 30 1990, so he was stil 10 years old, even more impressive!

Stig Gabrielsen is not an international master, not even in April 2016 when he is rated 2300, but a FIDE master, which is one rank below. He was born in 1976 in Norway, so at the time of this game he was 24 or 25 years old.

The game apparently left the theory with <9.Ne5N>, while at the time the most played move was 9.0-0.

The first imprecision was <12.f4?! Nc6 > Equality can be maintained with 12.Rd1 c4 (or 12...Nc6 13.Nxc6 Qxc6 14.dxc5 bxc5 = with the idea that if 15.Nxd5?! Nxd5 16.Qxd5 Rfd8! 17.Qh5 (not 17.Qxc6?? Rxd1#) Bf6 ) 13.Qf5 =

<13.Rf3?! cxd4! > Gabrielsen is following the wrong plan. 13.g4 with the idea that if 13...Nxe5? 14.dxe5! Nxg4 15.Nxd5

<14...Qxc6?! 15.exd4! > Carlsen missed the intermediate move 14...dxc3! 15.Nxe7+ (or 15.Qxc3 Rac8 16.Nxe7+ Qxe7 17.Qb3 Ne4! with the idea 18.Qxd5?! Rc2 followed with Rfc8) Qxe7 16.Qxc3

<16.f5> 16.a3!

<16...Ne4 17.Bf4 > 16...Bb4!

<22...a6?!> 22...h6! 23.Rf3 Rc4 24.Nc3 Qc6 25.Nd1 Rc2 /

<23.Na3?! Qa4! > Strange move. Now Black is winning. The only playable move is 23.Nc3 Nxc3! 24.bxc3 Qa4! 25.Qd2

<25...Nd6? 26.g4! > Oops. 25...b5! 26.b4 h5!

<26...h6?!> 26.Ne4

<27.Kf2?! b5! > I suspect Gabrielsen was starting to be short on time. 27.Kg2

<30...Rxb2?! > Winning, but much stronger is 30...Ne4!

<34...Kh7?!> Getting closer to the 40th move time control... Carlsen also probably getting short on time. 34...Re2! followed by d4-d3-d2 which will force White to give up a piece for that pawn.

<35.h4?! d4!> We are about to close the books... 35.Rb6 Re2! 36.Bf2 Nc1!

16.f5 is certainly not a great move, but it is not the cause of the defeat. I suppose Gabrielsen played this to open the line for his bishop on c1, in order to get some attacking chances on Carlsen's castling position?

The program Stockfish seems to prefer 16.a3! .

It appears the whole plan of f2-f4, Rf1-f3, then I suppose Rf3-g3 or Rf3-h3 was too optimistic in the first place.

As for 20.Rff1, it is like Gabrielsen was giving up on the idea of attacking Black's king position. He apparently decided to reinforce his back rank and getting the future possibility of challenging the c-file control.

Stockfish prefers 20.Nc3 .