
Kagawa, of course, was a main factor in both Bundesliga-winning seasons under Klopp, with the Japan international taking the league by storm after moving to Germany for a mere training compensation of €350,000 in 2010.
"When he left for Manchester United in 2012, my heart stayed with Dortmund," Akiyama said. "Shinji came back in 2014, but he's not even my favourite player at this point."
Ambrose followed the club since the start of the Klopp era: "There is no exact time or date, like with most fans, but I usually say [I became a Dortmund fan] around 2008. I started studying German at school in 2007 and watched more and more Bundesliga and gradually more and more of BVB than any other club."
Rose estimated he became a fan in 1995: "I was working at a coaching camp with some guys from Nordrhein-Westfalen, [the federal state where Dortmund is located in Germany], and I have a lot of heritage in the region."
What hooks international fans to the club? For Akiyama, it's the bond between players and fans: "Seeing the team in front of 80,000 people in Westfalenstadion blew me away. The fans support their team, even when the games aren't going well. That's rare."
The rise of social media and the expansion of media coverage of the club also seem important factors. "It makes everything about following the club easier," Rose said. "For a lot of years, I'd maybe get to see two or three matches a year, and it would have to be via satellite, so now I can be a lot more familiar with the players and how they’re doing."
Ambrose pointed out that: "When you are a fan from afar, it can be hard to get that genuine connection, but Twitter makes you feel a part of that community, and the official BVB account only adds to that."
The club's Twitter account is an interesting point. Unlike almost every other big European club, Dortmund don't have multiple accounts targeting different audiences. There's only one account, tweeting in both German and English, and it's followed by 2.35 million people at the time of this writing—for reference, only five Premier League clubs have more, per a ranking by the Sunday Express.
"In order to keep it real, we think it's the right decision," the club's editor of new media, Peter Flore, explained in an appearance on the Yellow Wall podcast. Given the struggles of the clubs that outsource the maintenance of accounts in different languages, that seems like a wise choice:

Whereas many fans follow the games over social media these days, Rose does it the old-fashioned way: "I am the co-founder of Die Brunnenstadt BVB, a soon-to-be official fan club here in Kansas City. We watch matches together at a local beer garden."
Because of the time difference, Akiyama watches from the comfort of her home. "Games start late in the evening or even in the night. For important Champions League matches, I set an alarm on my phone in case I fall asleep."
For her, the club's first marketing trip to Asia, in 2015, felt like winning the lottery: "It was incredible to see all the players in person." The 30-year-old was among a group of almost 1,000 people welcoming the team at the airport. "I got pictures with almost everyone. You never know if or when they'll return to Tokyo."
The club's marketing trips abroad and, generally, its efforts to become a global brand have been a hot topic among local fans, as detailed in an earlier piece, but Ambrose has a different view.

"I think it's fantastic," he told B/R. "Coming from England and now living in Germany, I am lucky to be close to the team. It's fantastic to see fans in Asia in recent years get the opportunity to see the team, and their reactions can be pretty humbling."
Indeed, German fans of the club would do well not to underestimate the dedication of those following the club from thousands of miles away. It's not uncommon to hear of fans scheduling their annual vacation in a way that allows them a trip to Westfalenstadion.
"I'll never forget having to drive three hours to watch the 1997 Champions League final but feeling like it was totally worth it," Rose recalled. Dortmund, of course, won that match 3-1 against Juventus, their biggest success to this point.
Ambrose was among the select few who got to watch the club in Wembley in 2013: "I've been fortunate enough to attend two finals [also the 2015 cup final against VfL Wolfsburg], though there are parts of those days I wish I could forget"—Dortmund lost on both occasions.
Watching a Black and Yellows match in Europe remains on Akiyama's bucket list: "It doesn't even have to be an important one, like the derby against Schalke or a big Champions League game. I just want to be on the Yellow Wall when the team walks on to the pitch."
She feels as though "only then I'll truly understand what it means to be a fan of this club."
As our three interviewees and thousands of other fans from all across the globe prove, however, is that you can be a genuine Dortmund fan despite being worlds apart from the club.
It seems it's that special feeling of unity and togetherness that makes the club so popular among international football fans. It's more than any one good season could ever accomplish.
All quotes obtained firsthand unless noted otherwise.
Lars Pollmann also writes for The Yellow Wall. You can follow him on Twitter.