Norway's Magnus Carlsen, the world's 23-year-old reigning chess champion, has launched an app based on his own past games to make chess more popular, but he'd prefer its players not get good enough to beat him.
Carlsen, whose talent and boyish good looks have earned him lucrative sponsorships deals and front-page coverage in his native country, is king of the roost in the chess world since beating Viswanathan Anand of India in November.
A grandmaster since he was 13, he already had the highest rating in the history of the game, ahead of chess great Garry Kasparov's 1999 record, and was the world chess number one.
Now he is the second youngest player to have become world champion - after Kasparov, by a few months, but he also can be his own toughest critic.
"I make positional mistakes, I make evaluation mistakes, tactical mistakes," he told Reuters in an interview on Tuesday. "I make mistakes in the opening, I make mistakes in the end games, I make mistakes in the middle games."
Anyone who wants to find out more about his playing style can do so with Carlsen's new app that allows users to play him at the different levels he has achieved since the age of five.
The app is built on hundreds of thousands of different positions from Carlsen's games, be they classical, rapid or blitz, to determine what moves he would make at those ages.
The aim is to promote chess among as many people as possible to make the sport more popular and accessible.
"The good thing is that you can play me at any age. At age five, anyone has a chance to beat me," Carlsen said.
So what is it like for Carlsen to play against his younger self?
"He is really tricky," the champion said. "Even Magnus at 11 years old was a very gifted tactician. A while ago I played as a test Magnus (aged) 14. I outplayed him at some point positionally. And just boom, boom, he tricked me tactically.
"But he makes mistakes as well, so I just have to be patient."
Can the app help find his next opponent?
"I am hoping it is going to create some competitors at some point. But I really hope it won't create anyone who is better than me. Because I don't want that," he said with a laugh.
His motivation, now that he is at the top, is to continue to improve his game.
"As long as I feel there is much to learn, that there is much refinement to be made, that is really a powerful motivation for me," he said. "And to continue to have fun."
(Reporting by Gwladys Fouche; Editing by Michael Roddy and Andrew Roche)