Everyone makes mistakes in chess. But even the best players on the planet — and by that I mean computers — are not infallible.

Still, when top players miscalculate badly, it can be a little comforting. (“Well, if they can do it, I don’t feel like such a patzer.”)

Last week, there were a number of such moments.

At the Tata Steel tournament in the Netherlands, Magnus Carlsen of Norway, the world’s top-ranked player, made a colossal mistake in Round 3 against Anish Giri, a 16-year-old Dutch grandmaster.

Carlsen was lackadaisical in playing the opening, but, as shown in the top diagram, he was not much worse off than his opponent. He should have tried 19 c4 when, after 19 ... Nc4 20 Qb4 Nd6 21 Ba3, the game would have been a long way from over.