On Saturday, a new chapter was written in South Korean football.
Although an increasingly-frequent occurrence in the cosmopolitan, modern age that is the world today, it has taken until now for South Korea to have their first foreign-born, mixed-race footballer in the men's national team.
As South Korea claimed an impressive 2-0 friendly win over United States in Harrison, New Jersey -- courtesy of goals from Son Heung-Min, the latest big-name import in MLS, and Lee Dong-Gyeong -- the 63rd-minute introduction of the Dusseldorf-born Jens Castrop saw him etch his name in the history books.
It -- being "foreign-born and mixed race" -- is officially a first for one of Asia's traditional powerhouses but it is not completely unprecedented.
Back at the 2023 FIFA Women's World Cup, American-Korean Casey Phair became the first mixed-heritage player in South Korean football although she did not classify for the first part of this 'status' given she was born in the country before moving to the States. Never mind the fact that she was only a month old when she left South Korea.
So even if it is just for the men's national team, a new era has now begun for South Korea.
So who exactly is Jens Castrop?
Early years
Born to a German father and South Korean mother, Castrop initially came through the youth ranks of local club Fortuna Düsseldorf but it was at Cologne where he would turn professional.
Curiously, he would never feature for Cologne's senior team.
Instead, his professional bow came during a loan spell with second-tier Nürnberg in 2022 -- a move was extended for a full season before being made permanent ahead of the 2023-24 season.
At that point, playing for South Korea appeared a distant proposition as he represented Germany at every age-group level, featuring for the U21s as recently as last season.
Where he's at now
After two impressive seasons in the second tier, Castrop caught the eye enough to earn a transfer to Bundesliga outfit Borussia Mönchengladbach ahead of this season.
It is certainly a big move for the 22-year-old given it will be his first taste of top-flight football, for a club who were playing UEFA Champions League football as recently as in 2020-21 -- although they have spent the past few campaigns settling for midtable mediocrity.
Castrop has featured in all of Gladbach's three matches so far this season, coming on as a substitute in league meetings with Hamburg and Stuttgart, as well as a DFB-Pokal tie against fifth-tier Atlas Delmenhorst.
How did he end up playing for South Korea?
Castrop's impeding change of allegiance had been mooted for some time but was pending FIFA clearance given his status as a former Germany youth international.
Once approval had been granted, it did not take long for South Korea coach Hong Myung-Bo to given Castrop his first call-up for the current international window.
"Although Castrop is young, he is a player who has consistently grown while gaining experience in the Bundesliga," said Hong at a recent news conference, while highlighting his new charge's "fighter-like, rugged style of play".
"Above all, I highly value the strong will and sense of responsibility he has shown to join our national team."
Castrop revealed he followed his heart in deciding to represent South Korea moving forward.
"It was a very tough decision," he said, according to Yonhap News Agency. "And I think, with his kind of decision in your life, you have to listen to your heart.
"And my heart said I want to play for Korea. And that's why I'm very proud that I'm here now."
Style of play
Castrop's physical and tenacious style of play makes it easy to think of him as a traditional box-to-box midfielder, and he does possess some perfect traits for that role.
Hong has already identified his combative presence in the engine room as something that is missing from his current crop of midfielders and some of his best moments come from barnstorming charges through the middle or late runs into the area.
Nonetheless, he could also prove to be a versatile option for both club and country.
Before settling in central midfield following his permanent move to Nürnberg, Castrop was deployed out wide and even in defence -- positions he is comfortable to be deployed in by his own admission.
Castrop's energy also means he has found himself as the most advanced of his team's midfield, even effectively as a second striker at times. It is a role he could easily perform given he is extremely comfortable on the ball, possessing a neat pair of quick feet that often help him get out of a tight situation.
Is he headed for the World Cup?
With South Korea through to next year's FIFA World Cup, could there be enough time for Castrop to force his way into the reckoning even though he played no part in their qualification campaign?
There is no reason why he can't, or won't.
South Korea have no shortage of star midfielders, from the metronome that is Hwang In-Beom to the incumbent No. 10 Lee Jae-Sung and even the enforcer in Park Yong-Woo, if extra insurance is needed to shield the backline.
All three featured prominently throughout the Asian qualifiers as a scalene, or asymmetrical, triangle, but none possess Castrop's modern mix of brute force and finesse.
Looking further down South Korea's engine room stocks, Lee Dong-Gyeong and Paik Seung-Ho make decent cases to be involved but both are the play-making type -- advanced and deep-lying respectively.
Lee was once on course to being the next big thing in South Korean football but his career has quite taken off after disappointing loan spells in Germany with Schalke and Hansa Rostock, and the same can be said of Paik, a Barcelona academy graduate who had to return to K League 1 to regain his footing before earning a return to Europe with in the third tier of English football with Birmingham, who have since been promoted to the Championship.
It will perhaps be too much of an ask for Castrop to force his way into South Korea's World Cup starting XI. It might even be a case of Hong being unwilling to fiddle with a system that has been working relatively well enough since he was parachuted into the role last July following the abrupt dismissal of Jürgen Klinsmann.
Yet, for a promising talent who will now spend the next nine months or so gaining invaluable experiencing at a new level that is one of Europe's most competitive domestic leagues, surely at least being involved when the World Cup comes around is well within his reach.