3.Bc4? White plays a pseudo-Italian game against the Sicilian.

7.Bb5+ Kf8 Instead of interposing a minor piece in response to check, the Black monarch steps away in hopes of trapping the White bishop with his queenside pawns. This ply creates a dynamic game where Black struggles to finish development and connect his rooks.

8.e5 Ng8 White gains space on the kingside, an advantage he will maintain throughout. The Black Ng8 will struggle to become useful.

10...Qxa5 Black is up a pawn, but his development will lag. A piece that cannot move is not much good.

11.c4 d4 A bind in the center is established, but the 17.b4 pawn break helps White to establish control of the center. Black remains on the defensive.

19.Qf3 establishes a deadly pin on the f7-pawn (threatening the devastating fork Nf6+) should the Bf4 move out-of-the-way with Bxh6+. So sees the threat and moves out of the way with 19...Kg7, putting the monarch on the long diagonal.

21.exd6 Wc8. White establishes a passed pawn while Black remains on the defensive. Instead, 21...Qc5 was a possibility.

22...Ngf6 At long last, the Black rooks are connected.

24.Bc1? with the idea of Bb2 giving unrelenting pressure on the long diagonal. 24...e5 in response finally gives Black some hope.

A series of questionable moves occur.

30...Rxd6 equalizes.

31...Rxd4! drops the exchange for four points but relieves Black of worry about pressure from the Bb2.

33.Re7? Nc5? Stockfish says 33...Qc5 would be winning.

35.Qh4 is winning for White.

35...b3? There's no time for this, is there?

36.Kg2 prepares for Rh1 with a scary battery on the open h-file. Instead, Stockfish begs for 36.f4 Nd3 37.R1e2 Nxf4 38.Qxf4 d3 39.Rf2 Qf5 40.Qxf5 +- +5.53 (33 ply)

36...Qf5 and now 37.Rh1 does not work on account of 37...Qxg5+ and the queens will be exchanged.

37.R7e5? Stockfish still begs for f4.

38.Rd5? Qc7? The players are starting to feel the time pressure.

39.Rh1 Finally, and White is winning.

42.Ne6 sets a fork but Stockfish says 42.NxNh7 would put White in the winner's circle.

The big moment has arrived:

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43.QxNh7? The game's worst blunder by far. The attacker violates a chess principle and allows an exchange of queens with 43...QxQh7. Now Black can breathe a sigh of relief. White should have simply executed the fork with 43.NxRf8, clearly winning.

44.RxQh7 Kxh7. So misses the intermezzo 44...Rxf2+ with a won game.

The players have been in a time scramble with the moves coming fast and furious. Both players were making moves under ten seconds each. I believe So ran out of time, but Carlsen was too busy to notice, and time (a few seconds) was added to So's clock as was the case for both players after every move.

46...b2 47.Rxb6. The Black queenside majority finally comes into play. Then the a-pawn surges forward. With the passer on b2, the rook will only be able to stop one pawn or the other, but not both.

55.Rd7! Has Carlsen found his escape? 55...b1=Q would have been a blunder on Black's part. See diagram of the promotion that did not occur:

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Had Black promoted, White has a Knight windmill for perpetual check beginning 56.Nh7+ (do teach this pattern to your students, as the White Nf6 and the Rd7 are ideally placed). Furthermore, if the Black monarch unwisely goes into the corner, White would have an Arabian Mate. See diagram of Arabian Mate:

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So did not fall for it. Although still under time pressure, he took the time to check for check, and voila! 55...Nf4+ 56.Kf3 Nh5 prevents White's perpetual check stalemate.

Thus 7...Kf8 lead to a complicated, dynamic game and many mistakes by both colors. Just when it looked like White had control of the center, kingside, and long diagonal the tide changed in part to So's exchange sacrifice in the center.