With Jude Bellingham expected to join Borussia Dortmund this month, Sky Sports News looks at why the Birmingham youngster has turned down Manchester United, Real Madrid, Bayern Munich and Chelsea to follow in the footsteps of Jadon Sancho and sign for the Bundesliga club.
The mantra of Manchester United legend Sir Matt Busby, that "if they're good enough they're old enough", could haunt Ed Woodward and his recruitment team for years to come if Bellingham becomes another highly-rated youngster to decide against a move to Old Trafford in favour of the Westfalenstadion.
Back in January, another United target, Erling Haaland, chose Dortmund over United - and has already scored 16 goals in just 18 appearances.
Who are Dortmund looking to recruit?
In simple terms, the very best 16-19-year-old footballers in the world.
Despite Sancho's time at the club, and Bellingham's expected arrival, Dortmund do not have an over-riding fascination interest in English talent. Unlike Bayern, Barcelona and RB Leipzig, they have no full-time scout in the UK, although the club is considering a change to that policy.
"Dortmund scouts for young talent at big clubs all over Europe - like Jadon Sancho at Man City, Dan-Axel Zagadou at PSG or Mateu Morey and Sergio Gomez at Barca," explains Sky Germany's Dortmund reporter Jesco von Eichmann.
"When these players realise that Dortmund have more trust in them than their present club do, then they are willing to make the change.
"Dortmund give them a perspective to develop - on the pitch, not on the bench."
How do they manage to beat off the competition?
Those tasked with luring the likes of Haaland, Giovanni Reyna and Sancho can call upon a host of attractions in joining Dortmund.
The football-mad city, the packed stadium with its famous Yellow Wall terrace, competitive wages and a reputation for developing young talent all help build an attractive package.
"Normally every potential new player gets invited to a match at the Westfalenstadion - so that they can feel what football means in this stadium," says Von Eichmann.
Paul Lambert, who won the Champions League with Dortmund in 1997, says the fans and the stadium were a big pull for him: "The fan base is unbelievable, it's one of the best-supported clubs in the world," he told Sky Sports News.
"Everyone knows the Yellow Wall, it's famous around the world and when you play there it's a special place.
"I went back there after I finished and stood there with the fans, what an atmosphere. I'm glad I played in front of it and I'm glad I stood on it and I would go and do it again. It's a special place to play football."
Unlike their competitors, Dortmund offer that most precious of commodities - guaranteed game time.
They find the best, then they blood them.
They do not offer 10-12 leagues games a season and a place on the bench in the Champions League.
They offer 40 league games and a starting XI shirt in Europe. In terms of time on the pitch, the likes of Barcelona and Real Madrid simply cannot compete.
They are not recruiting academy prospects to Westphalia…they are recruited as first-team players.
It is that simple?
In essence, yes. Dortmund, however, do employ one other unique selling point in their unprecedented recruitment drives.
For most clubs, the weekly meeting over transfer targets will list their first, second, third, fourth and possibly fifth choice targets to fill a vacant position.
Dortmund are different.
Having identified their talent, they focus their time and energy purely on him. They do not have second or third choices. And they make sure their No 1 target feels like a cherished part of the Dortmund family, even before they sign.
If, as expected, Bellingham joins Dortmund, it is not a far stretch to think that in three years he will have 100 Bundesliga appearances, 30 goals and 25 Champions League matches under his belt…and possibly some German silverware to boot.
It is then, perhaps as one of the most experienced top-level 20-year-olds in Europe that the likes of Bellingham and Haaland will likely move onto the Bernabeu, Nou Camp, or perhaps Anfield or Old Trafford.
For Dortmund, they will reap the rewards that Europe's biggest clubs will have to part with to land their talents.
Haaland's worth could well have trebled since his £17m move from Red Bull Salzburg in January.
Both Manchester United and RB Leipzig remain at a loss as to how they missed out on signing the Norwegian striker. Leipzig in particular carried out an internal inquiry to work out how they managed to let Haaland slip out of the Red Bull net.
One of Haaland's best pals at Dortmund is 17-year-old Gio Reyna. Amazingly, Gio ignored the lure of a move to Man City and chose Dortmund when he left New York City FC. This, despite his father Claudio being a former City player and sporting director of the MLS team owned by City's global football group.
And it is Reyna who is perhaps the best example of how Bellingham could progress should he join Dortmund. "He will need some time to get used to it and get integrated," says Tobi Joehren, the Dortmund correspondent for Ruhr Nachrichten.
"You probably can compare him to Gio Reyna who arrived last summer. He had six months with the U19s and some experiences with the first team before joining up with them in the winter and now he's already important.
"You should give a little bit of time to Jude Bellingham and don't expect crazy things from him, but they are really convinced he will help them otherwise they wouldn't pay over 20m euros for him.
"He will hopefully find his way but it will take six months to get into it, then we will see how long it will take for him to be an important part of the team."
They do not land all the top young talents, however. Earlier this season Chelsea pipped a host of Europe's finest to land Jimi Tauriainen, a prodigiously talented 16-year-old from Finland.
When did Dortmund's youth-first policy begin?
Having flirted with bankruptcy in 2005, the club spent several seasons offloading their top earners, building a system to attract and promote young players to take their place.
Since then they have made huge profits on the likes of Shinji Kagawa, Ilkay Gundogan, Pierre-Emerick Aubameyang, Ousmane Dembele and Christian Pulisic, landing back-to-back Bundesliga titles in 2011 and 2012.
As other clubs try to replicate their strategy Dortmund have been forced to recruit increasingly younger players. They first watched Bellingham when he was 14.
The club recently spent £17m updating their Hohenbuschei training and scouting headquarters to help guarantee the club's continued success in an increasingly busy youth market.
While there is an emphasis on youth at Dortmund, first-team places are not just handed out as a matter of course: "You've got to earn the right to get in the team," says Lambert. "I don't think you can guarantee someone a game just because you're a young player.
"Borussia Dortmund have to win. They have to try and win the Bundesliga or the German Cup or European trophies. It's a huge club. They're not going to bring you in to give you a grounding, develop you and then move you on. They want to win trophies and I don't think you should get away from that."
Who's who behind the scenes at Dortmund?
Few people understand Dortmund's DNA better than sporting director Michael Zorc. Their record appearance holder (463 games), Zorc is the link between first team coach Lucien Favre and the club's CEO Hans-Joachim Watzke.
Under Zorc's steady hand Dortmund have won three Bundesliga titles, two DFB Cup wins and reached two European finals.
Head of scouting Markus Pilawa joined Dortmund from local rivals VfL Bochum in 2012. As well as co-ordinating their global talent search, Pilawa believes Germany is now behind countries like England in developing youngsters and hopes to boost the club's limited success in promoting talent from their academy into Favre's first team.
"In December 2017 Dortmund lost their former chief scout Sven Mislintat to Arsenal, his reputation of finding talents like Sancho or Dembele was great. But Pilawa and his team have only built on Mislintat's success," says von Eichmann.
Pilawa has also recruited more experienced talent, including Mats Hummels, Emre Can, Thorgan Hazard and Julian Brandt to help build a balanced squad capable of winning trophies.
Other clubs replicating Dortmund's business model has seen them spread their nets wider, concentrating recent scouting missions in less traditional hunting grounds, notably Asia and the US.