Norwegian prodigy Magnus Carlsen is the Tiger Woods of chess. In a good way. Just as Woods, before his fall, established an iron grip on golf, so Carlsen, at the age of 22, has made himself supreme in his own more esoteric field. He became world No 1 while still a teenager, and is now officially rated the strongest player of all time.

What he is not, however, is world champion. That title has been held since 2007 by India's Viswanathan Anand, a great player but 20 years older than Carlsen and now rated only No 6 in the world. The time may be ripe for the young genius, and, in a three-week tournament that starts in London on Thursday, Carlsen and seven other top grandmasters will compete for the right to challenge Anand for his crown later in the year.

The so-called Candidates tournament is the strongest ever, and the Norwegian will be warm favourite. Chess, which has been marginalised since the heyday of Bobby Fischer in the 1970s and Garry Kasparov in the 80s, is desperate for a new story to tell, and an intergenerational clash between Carlsen and Anand would provide one, especially in India, where Anand is feted as much as any cricket star.

Carlsen is not taking success in London for granted. "Having a high rating doesn't help me in the Candidates," he says. "The others won't be intimidated." But nor is he given to false modesty. "I have no doubts that when I am playing at my best I am the best. The ratings don't lie."

He is an odd combination of shyness and self-confidence. Socially reserved – though less so than he used to be – he nevertheless enjoys being No 1.

"It's important to be self-confident and optimistic," he says. "If you're not optimistic, you're not going to grab your chances when they're there."

We meet in the plush Oslo waterfront offices of one of his Norwegian sponsors, legal firm Simonsen Vogt Wiig. Carlsen is wearing fashionably distressed jeans and an expensive-looking striped shirt emblazoned with his sponsors' names. Almost singlehandedly, he is trying to bring chess into the world of 21st-century sport. He earns €1m (£870,000) a year, has a full-time manager, has just been on a two-week training camp in the Canary Islands and for a couple of years was the global face of Dutch fashion company G-Star Raw. For the Cinderella sport of chess, Carlsen offers hope of a ticket to the ball.

In common with most top players, he started playing when very young. He was five when his father, Henrik, a good club player, showed him and his elder sister the moves. But he didn't take to the game immediately, and only when he was eight did he start to make rapid progress. "He's a bit of a slow starter," says Henrik Carlsen of his son. "My explanation is that his logical wiring is so complex that it takes a bit of time to set it up; then he starts moving and, whoosh, he just keeps going."

Carlsen's father and mother are both engineers, and from the age of two he showed prodigious problem-solving and memory skills. Once he applied them singlemindedly to chess, there was no stopping him. He became a grandmaster at 13, was world No 1 at 19, and last year became the top-rated player of all time.

When he was 12, he took a year off school, and the family travelled round the world, combining chess tournaments with sightseeing. It was both a bonding exercise and a vital part of Carlsen's chess development. Originally, the intention had been for him to combine chess with a general education, but increasingly the latter had to take a back seat and he chose not to go to university, preferring to concentrate on chess.

Magnus Carlsen, aged 14 – he became a grandmaster at 13. Photograph: Monika Flueckiger/AP

"If there was an interesting tournament," says Carlsen, "I thought there was no reason to go to school instead." "Most of us are occupied with mediocre activities in every direction," says Henrik, "so if there is someone with a talent and an interest to do something extraordinary, then why not? At least we should not stop him. If he wants to stop, fine." But Carlsen never did want to stop.

"Magnus is a maximalist," says his manager, Espen Agdestein. Whatever he does, he wants to do to the utmost. He is a fanatical follower of basketball, having to learn every detail about every player and every team. For a while, says his father, he was interested in poker and became brilliant at it. "He could do the statistics of the poker hands quicker than me," says Henrik, "and I'm quite good with numbers. In a few months he had picked up all he needed to be extraordinary. He likes to go into things very deeply."

His father says the secret of nurturing his genius was to let him do what he wanted – a very Norwegian approach. "In the conventional sense he's lazy," says Henrik. "If you had told him to do something that he wasn't motivated to do, he wouldn't do it. But I don't think that sort of laziness hurts his chess. What's important is his interest, competitiveness and curiosity. He's always done what he wants in chess, and he's there because he loves to be there and fight, whereas many of his rivals have already spent a lot of their energy by the time they arrive at the table."

Carlsen is an unusual player. He plays a wide range of openings and shows less interest in theory and preparation than many grandmasters, preferring to take games down unconventional avenues and think through problems over the board. He also dislikes draws, opting to fight to the bitter end. Being young and in excellent physical shape gives him an advantage over his older rivals in draining games that can last up to seven hours.

"Draws are a natural part of the game, but agreeing to an [early] draw is not natural," says Carlsen. "It's not within the flow of the game. I'm usually surprised when my opponent makes a mistake after a very long time. I don't expect it to happen. But it happens so often that it makes perfect sense for me to always try till the end."

How does he cope with his occasional defeats? "I get very upset. But I try to do something positive with it in that I'm really focused and angry and I want to win the next game, and that's what I usually do. I'm like a wounded tiger after I've been beaten."

Carlsen lives in a flat in his parents' house in a suburb of Oslo, but as a peripatetic chess pro he spends more than half the year outside Norway and is thinking of buying an apartment in London or New York. So far, romantic entanglements have not diverted him unduly from the delights of the Sicilian defence. "It's hard to sustain relationships when I'm travelling all the time, so most of my flings, if you would call them that, have been fairly short-lived. Perhaps as I get older I will find something more stable and long-lasting."

He sees the Armenian world No 3, Levon Aronian, as his most dangerous opponent in London. "He has supreme confidence and belief in himself, is very well prepared, can evaluate non-standard positions very well and never backs down," says Carlsen in a tribute to a fellow chess optimist.

Would Carlsen be disappointed if he failed to make it through to the world championship match? "It would depend on the performance," he says. "If I score plus four and Aronian scores plus six, I will probably have had a quite good tournament and there's not much I can do. If I feel I haven't been able to show my best, then I will be disappointed. But life goes on, and whether I win or lose I will still be 22 with most of my career ahead of me."

How long his career will last is an interesting question. Many chess players are lifers. They know nothing else and carry on playing forever, even though after 40, as body and brain cells age, the only way is down. But Carlsen is adamant he will not accept gentle decline or the indignity of a plummeting rating. Again, he compares himself with his peers in other sports, who recognise that their careers are likely to be short.

"My peak should last into my mid-30s," he says. "I probably wouldn't be as sharp then as I am now, but I will have more experience and know more, and if I'm in good shape I would still be able to endure long tournaments. But for my rating to go under 2,700 [it is currently a stratospheric 2,872], I don't think that would ever happen. I'll retire before that. I can't picture myself playing that far from my peak."

He also holds out the prospect of taking a sabbatical from chess at some point. "I will play as long as I'm motivated, and then I'll either take a break and resume when motivated, or just quit. The earlier the time comes when I'm not motivated, the greater are the chances that I will come back after I take a break, but you never know."

You sense Carlsen would never just go through the motions. The €1m a year comes in handy, but what really drives him is passion and intellectual curiosity. "Sometimes I feel that I'm able to create something special," he says, "and I very much like the game of ideas between the two players. It's captivating, it's fun, and it keeps me going."

Carlsen's rivals in London

Vladimir Kramnik

Levon Aronian. Photograph: Yasuyoshi Chiba/AFP/Getty Images

Sophisticated Russian who was world champion from 2000-2007. World No 2 and rarely puts in a poor performance, but at the age of 37 his veteran status may count against him.

Levon Aronian

The Armenian world No 3 is the opponent Carlsen fears most, and they will go head to head on Friday in a crucial early game. At 30 he is at his peak, and carries the hopes of chess-mad Armenia. A highly creative, tactical player.

Vassily Ivanchuk

The Ukrainian is 43 and has been one of the world's top players for a quarter of a century. Many consider him the best player never to have become world champion. Eccentric and unpredictable.

Peter Svidler

Witty, likable, anglophile, cricket-mad Russian who qualified for the Candidates tournament by winning the Chess World Cup in 2011. Rated No 14 in the world.

Alexander Grischuk

Another immensely strong Russian, rated No 10 in the world. A decade younger than his compatriots Kramnik and Svidler.

Teimour Radjabov

Born in the chess hotspot of Baku, Garry Kasparov's birthplace. Became a grandmaster at the age of 14. World No 4 who will be 26 this week. Was given a wild card to the Candidates, in part because the tournament is backed by Azerbaijani money.

Boris Gelfand

Solid positional player born in Belarus but now resident in Israel. Lost to Anand in last year's world title match. Unlikely, at 44, to mount another challenge for the crown.