This article is part of the Guardian's World Cup 2014 Experts' Network, a co-operation between 32 of the best media organisations from the countries who have qualified for the finals in Brazil. theguardian.com is running previews from four countries each day in the run-up to the tournament kicking off on 12 June.

A few months ago, I received a job offer to go and work at the J-League club Vegalta Sendai. It would have meant waving a sorry goodbye to the intoxicating vibrancy of Kansai, western Japan – home of manzai comedy, home to the world's greatest food city (Osaka) according to Michael Booth in the Guardian, and the only home I have known in this country for over a decade. My prospective new digs would be over 500 miles away in the remote Tohoku (literally 'northeast') region, where I knew absolutely nobody, where temperatures were five degrees colder but humidity somehow 10% higher, and where – as tragically witnessed on 11 March 2011 – tectonic activity is particularly intense even by the standards of a country formed at the junction of four different plates.

To be honest, I cannot deny feeling a certain relief when a change of circumstances took the decision to uproot out of my hands. But this was the very decision taken by Shinji Kagawa, entirely of his own accord, at the tender age of 12.

Born in Kobe in 1989, four years before the official launch of the J-League, Kagawa was part of the first generation of Japanese boys for whom it was relatively common to grow up dreaming of becoming a professional footballer. However, there was nothing childlike about his level of ambition. As a spindly 10-year-old, he was given the opportunity to spend the primary school summer holiday training up in Sendai with FC Miyagi Barcelona, a youth football club not officially affiliated to the blaugrana in Catalonia but famous for encouraging the art of dribbling. There, as the director Noboru Kusaka recounted to Soccer Critique magazine last year, Kagawa spelled out exactly how he planned to reach the top.

"I'm going to join a J-League club's development scheme, get picked for regional select teams and play in national tournaments. If I can't do that, I'll play for a normal local club, do my best there so I can join a J-League youth team or a famous footballing high school when I am 15, and then work hard to turn pro. It might then take two years to make the first team, but I'll be patient and once I get a game, I then want to be picked for the Japan under-age teams and finally the full national side."

Kusaka was duly impressed both by the youngster's plan and by his execution on the pitch. "Even then," he says, "Shinji understood it wouldn't all go smoothly. He knew exactly how good he was, where his assets were, in which areas he was lacking and what he needed to do about them. From that age he was capable of constructive self-evaluation, and this hasn't changed ever since." Just 18 months after his initial spell at FC Miyagi Barcelona, Kagawa left his parents' home to move up to the other end of the country on a permanent basis.

The new environment allowed him to focus on developing his technique and suited him so well that he decided to stay on at the club upon reaching high-school age. The decision bore fruit as, in September 2005, the 16-year-old Kagawa was called into the Tohoku under-18 select squad to appear at the Sendai Cup – a famous international youth tournament whose future alumni would include Oscar, Yann M'Vila, and Alexandre Pato.

Following defeats to Lucas Leiva's Brazil and Nikola Kalinic's Croatia, the local side played their final group game against the Japan under-18 team. Deployed at the base of midfield, from where he had plenty of space to show off his dribbling skills, Kagawa repeatedly bamboozled a defence containing his now Brazil 2014 team-mates Maya Yoshida and Atsuto Uchida, and was involved in three goals as Tohoku thrashed the rest of the nation 5-2.

By now, Kansai was calling him back home. Youth football in Japan is closely associated with the education system – with famous sporting high schools and universities akin to those in North America – and even those who take the European-style club or academy route will rarely change direction outside the school graduation ages of 12, 15, 18, and 22. But with half a dozen J-League clubs now swarming around the star of that Tohoku select team, Cerezo Osaka needed to act quickly.

Their scout, Akio Kogiku, had happened across Kagawa more than a year previously when visiting Miyagi to watch the goalkeeper Kenta Tanno. Kogiku urged his bosses to make the move, recalling how he had been instantly impressed by the midfielder's desire for the ball, sense of control, and the sheer manner in which he immersed himself in football even away from the pitch. A contract was presented in December 2005, and Kagawa became the first player ever to sign professional terms with a J-League club midway through his high school education without previously having been part of its youth set-up.

Kagawa's first season at Cerezo was a difficult, but important learning experience. Criticised for his lack of speed, he failed to make the first team but instead worked hard on his physique, his quickness of touch, and his football brain to rectify the problem. According to Kogiku, it was Kagawa's genuine love of the game that moved him to think more about diet, gym routines, and how to analyse opponents' moves before they made them. This effort was what stood him apart.

The breakthrough year came in 2007, when the Brazilian Levir Culpi was appointed as manager and immediately told Kagawa he would be a starter – albeit in an unfamiliar, more advanced midfield role where he could develop as a goalscorer. By now aged 18, the Cerezo No26 thrived on the freedom and faith placed in him. From late May onwards, he started every J2 (second division) game for which he was available and netted five times. This tally rose to 16 the following year, and when he was given the club's famous No8 shirt in 2009 after the retirement of the Japan legend Hiroaki Morishima, he contributed an astonishing 27 goals and 13 assists as the pink half of Osaka sealed their return to J1. Seven goals in his first 11 top-flight appearances, and the Bundesliga's Borussia Dortmund came calling.

Kagawa can still show signs of mental fragility. Culpi famously once contrasted him with Yoichiro Kakitani, now an international team-mate, saying: "Shinji has a great sense of responsibility as a professional, but this means he fears making mistakes. Conversely, Yoichiro is irresponsible, but this makes him capable of great bravery."

But no matter how much he may have suffered in the David Moyes era at Manchester United, ahead of his first World Cup he just needs to think back to his roots, and to all the coaches from Kusaka to Jürgen Klopp he has wowed, to remember he is already one of the most special footballers in Japanese history.

Ben Mabley is an Osaka-based football writer and television pundit for JSports

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