Oslo, May 30 -- One of the first things Henrik Carlsen told Peter Heine Nielsen was not to have ambitions on his son's behalf: "If Magnus doesn't want to prepare, it's his decision." Magnus Carlsen was 13 years old at the time.

The standing instruction has not hurt. More than two decades later, Nielsen can call himself coach to a generational talent, a five-time world chess champion, the world No 1, and arguably one of the greatest players in the history of the game.

"I mean, it sounds wrong to say it perhaps, but I have never seen Magnus as very ambitious.that's maybe because he's won everything. Here at Norway Chess this year, he lost two out of his first three classical games and if I do the math maybe it doesn't seem too likely that...