That he couldn't resist the lure of the club with whom he won two league titles and the DFB Cup is common knowledge, but what else is there that drives the Japan international? bundesliga.com has dug up ten facts that you might not have known about Borussia's latest prodigal son...
Kagawa was born in 1989, four years before the formation of Japan's official J-League, and he was part of a generation of boys for whom a football career seemed a realistic possibility. As a kid he spent the summers with FC Miyagi Barcelona, a boy's club in the city of Sendai, 500 miles from his home in Osaka. The club wasn't affiliated to its famous namesake FC Barcelona but it shared the latter's principles of individualism and flair, skills that would become two of Kagawa's hallmarks.
At the age of 16, Kagawa was invited to play for a regional select XI against a Japan Under-18 side that then included current FC Schalke 04 defender . He was the star of the show in a 5-2 win, after which almost every club in Japan wanted his signature. He eventually joined Cerezo Osaka just three months later, becoming the first player in history to sign for a professional club midway through his high-school education and without having been part of the club's youth side.
After becoming the Japanese second division's top scorer and helping Cerezo to promotion in 2009, he was signed by Borussia Dortmund in the summer of 2010. Little was expected of the small, spindly-looking attacker at first, but he announced himself in Germany in sensational style by bagging a brace at FC Schalke 04 in the Revierderby on only his fourth league appearance. His place in BVB folklore was thus guaranteed almost instantly.
Kagawa's two seasons at Signal Iduna Park coincided with two of the most glorious years in the club's recent history: a Bundesliga championship triumph in 2011, nine years after their last, and a domestic double - the first in BVB's history - in 2012. He scored 21 goals in 49 league appearances, and in a final act of brilliance before his departure, netted the opener and assisted another in a 5-2 win over FC Bayern München in the 2012 DFB Cup final.
Sir Alex Ferguson, legendary coach of Manchester United FC, was there to witness Kagawa dismantle Bayern and he made the midfielder a Man Utd player that summer. Kagawa lifted the Premier League title in his first year at Old Trafford, but fell down the pecking order under subesquent coaches David Moyes and Louis van Gaal, opting to return to BVB in 2014. "I believe BVB and Kagawa did everything right. Shinji is back in surroundings where he feels like a fish in water," Ferguson commented.
The decision to re-join BVB where he can play regularly can in part be explained by Kagawa's disappointment following the 2014 FIFA World Cup. Japan had impressed at the Confederations Cup a year before, but took just one point from games against Greece, Colombia and Cote d'Ivoire. "We can play well as a team, but in terms of individual quality, we're not good enough. This is not the end of my career, so I want to make the best of this frustration and disappointment," he said candidly.
"I said when I left Dortmund that Borussia and I were not finished yet," Kagawa beamed after re-signing for BVB on transfer deadline day in August. "Now I'm just happy to be back here with such a great team. This club are like a family and I'm happy they never forgot about me." He was put straight into the starting line-up for Matchday 2's game at home to SC Freiburg - the last team he had faced in the Bundesliga - and scored in a 3-1 win. A better script couldn't have been written.
Returning to BVB has meant he is now once again face-to-face, and side-by-side, with compatriot Uchida. Despite being on opposite sides of Dortmund and Schalke's passionate rivalry, the two have remained close friends since they first arrived in Germany, and Uchida for one is delighted Shinji has returned. "When he was in Manchester, I kept telling him to come back!" revealed the defender. "We're good friends, we meet every day in Düsseldorf for Sushi."
"The style of this lively player is reminiscent of the filigree writing of calligraphers," opined one journalist when Kagawa signed for Man Utd. Indeed, the belief that Kagawa's movement on the pitch and abilities with a football are a form of art is one held by many. As nimble as a fish in tight spaces and possessing an angelic touch, there's no doubting the league has been enriched by his return. "He's extremely welcome back in Germany," said none other than Bayern CEO Karl-Heinz Rummenigge.
Aside from his talent, it's his incredible drive that has made Kagawa one of Japan's greatest ever players, and former Miyagi director Noboru Kusaka still remembers how the boy from Kobe outlined his path to the top: "If I can't join a J-League club's development scheme, I'll play for a local club so I can join a J-League youth team or a high-school team when I'm 15, and then work hard to turn pro. Once I'm in the first team, I want to be picked for Japan youth sides and finally the full national team." You'll be hard-pressed to find a 12-year-old with confidence like that.