The shortest game of the match so far and in fact there was only one critical moment in it.

Carlsen opened with 1 c4, adding more options right from the start. Would Caruana try to go for QGD set-ups with 1…e6 or would he go symmetrical with 1…c5 or would he go for a Reversed Sicilian with 1…e5? Caruana chose the latter and they followed his recent game against So, from the Paris Grand Chess Tour blitz.

Carlsen introduced a novelty, the engine’s first choice and naturally Caruana wasn’t surprised even a bit, so he continued to blitz out his moves. Carlsen declined the invitation to force the game immediately with 12 Nd4 and chose the preparatory 12 Rb1.

After this move Caruana stopped to think for a while and I am not sure whether he was trying to remember his preparation and if he succeeded because after 12…Nf3 (12…Bg4 was interesting) 13 Bf3 his move 13…a6 appeared to give White a promising possibility.

That was the critical moment of the game. After a really long think, “to b5 or not to b5” Carlsen chose the latter and the game quickly lost its edge. In the analysis I found it hard to find a straight-forward way for Black towards equality after 15 b5. Probably there is one, but it is quite certain that playing b5 would have put more pressure on Caruana.

After Carlsen’s choice of 15 Re1 Caruana didn’t have any problems whatsoever. In the ensuing endgame he efficiently solved all his problems.

Another White game went to waste for the players. But things are slowly starting to change – in Game 3 Caruana had an advantage after the opening, while today Carlsen had the promising option of 14 b5. The players still do not make the maximum of their chances, but they will.

The match is also approaching a turning point because after Caruana’s next White game in Game 5 it will be Carlsen with two Whites in a row and it is clear that he will do his utmost to score in at least one of them. Interesting times ahead.