Sergash: Victor André Nøstvold Hansen is a player from Norway, born in 1982. He doesn't seem to have any other title than chess Expert.<4.Qd1xd4!?> A unusual move, but playable. Until now in official Carlsen's games, we only had seen 4.Nf3xd4 here, which had occurred in several past games of the boy. Probably played as a surprise move. It doesn't lead to any opening advantage for White though.
<4...Bc8-d7?! 5.c2-c4 Nb8-c6 6.Qd4-d2 Ng8-f6 7.Nb1-c3 g7-g6 8.b2-b3 Bf8-g7 9.Bc1-b2 0-0 ⩲> The most played and obvious move here, is 4...Nb8-c6 with the main line going 5.Bf1-b5 Bc8-d7 6.Bb5xc6 Bd7xc6 etc. as seen in the 1936 Munich Olympiad game V Uulberg vs L Kremer, 1936, 0-1.
There is also 4...Ng8-f6 5.Nb1-c3 Nb8-c6 (or 5...a7-a6 Mihailo Trajkovic vs Janosevic, 1955, 1-0) 6.Bf1-b5 Bc8-d7 7.Bb5xc6 Bd7xc6 ▢ 8.Bc1-g5 e7-e6! etc. Thorkild Haahr vs. Ernst Ahman, Sweden vs. Denmark in Saltsjöbaden (Sweden) 1948, round 2.9, 0-1.
<10.Bf1-e2 ⩲> A greater precision apparently goes to 10,h2-h3!? ⩲ as played in the game Jacek Bednarski vs. Anthony Fred Saidy, 7th Rubinstein Memorial in Polanica Zdroj (Polland) 1969, round 2, 1-0.
<10...Bd7-g4 11.0-0 Qd8-a5 = / ⩱> It seems better to bring in a new piece into play: 10...Qd8-a5 11.Ra1-b1! a7-a6 12.a2-a3 Bd7-g4 13.0-0 (as in the game Smejkal vs Ulf Andersson, 1969, 0-1) Rf8-d8! = / ⩲ Stockfish 11 - 64 bits POPCNT, with a possible transposition into Theory if White plays 14.Rf1-d1 or 14.Rb1-d1 .
<12.Ra1-d1 => In truth, putting the f1 rook on that square would be more logical: 12.Rf1-d1! = / ⩲ as played in the game Astra Ergle vs. Natalia Konopleva, USSR Team Championship 1962 in Leningrad, draw, after which the a1-rook could be placed on b1 or c1.