Shinji Kagawa's move to Borussia Dortmund paved the way for silky Japanese players to make the Bundesliga their go-to European league with Eintracht Frankfurt's Daichi Kamada and Arminia Bielefeld's Ritsu Doan among those to follow in his footsteps.
There had been Japanese players that had shone in Germany before. Yasuhiko Okudera signed for Cologne in 1977 to become the first emerging star from the land of the rising sun in the Bundesliga, while Kamada's Frankfurt teammate Makoto Hasebe has made Germany his home since joining Wolfsburg in January 2008.
But none have had the impact of Kagawa, at least not yet.
Watch: Kagawa-mania on tour in Japan
"He told me that Dortmund became champions of Germany because I had played for them," Kagawa explained to Goal.com, recounting a conversation he had had with Jürgen Klopp, his former boss at BVB.
"Of course there were other players, but that really lifted my confidence. 'You don't need to worry,' he told me. I didn't worry. Those words made me happy, I'll never forget that moment."
Kagawa had actually been invited to Europe for trials with Schalke and Bayer Leverkusen as well as Dortmund. The Royal Blues' and Die Werkself's loss was most definitely the Black-Yellows' gain as Kagawa - notably in his second season with 13 goals and 12 assists in 31 league games - helped Klopp's squad to back-to-back Bundesliga crowns.
Kagawa took time to really take off at BVB, and Kamada's Bundesliga career has taken still longer. At Frankfurt since 2017, he made just three top-flight appearances in his maiden season in Europe, and it was only after a successful 2018/19 loan spell at Belgian outfit Sint-Truiden during which he netted 16 times and recorded nine assists that he came to the fore.
"I have to admit he's really surprised me - in a good way! He's come on in leaps and bounds, not just as a player but his character has really come to the fore, too," admitted coach Adi Hütter.
"Of course we followed his path and his goals in Belgium, but our initial thought was to send him out on loan again. After three days of training, we looked at each other and said, 'That's not the Daichi from before'. We could have let him go, but I told [sporting director] Fredi Bobic that it was better to keep him."
Hütter's instincts were proven right. As impishly creative as Kagawa, Kamada was a key creative element for Frankfurt after they lost Sebastian Haller, Ante Rebic and Luka Jovic ahead of the 2019/20 season. Though he impressed for little reward in the Bundesliga, he was the stand-out performer as the Eagles flew to the Last 16 of the UEFA Europa League.
"He was brilliant, he's a fantastic player," gushed Bobic after seeing Kamada score twice to earn a 2-1 group-stage win at Arsenal. The Japan international then followed that up with a hat-trick against Red Bull Salzburg in the Last 32 to leave a significant mark on the competition.
Watch: Kamada on target as Frankfurt beat Hoffenheim
It also made an impression on his club, who were delighted to sign him to a new contract early in the 2020/21 season. "Daichi Kamada is a perfect illustration of how we are able to develop and nurture young players," said Bobic after adding two years to the attacking midfielder's deal, which had been due to expire at the end of the current campaign.
"The loan also did him good. He made great progress in Belgium and was very impressive for us last season. We're pleased that Daichi has decided to stay with us. We're sure he can play an important role in our team in the coming years."
Kamada already has, netting once and registering three assists - a tally which would have been significantly more had more of his 22 passes to a shot or league-high 42 crosses been finished off.
If Kamada's Bundesliga career was kickstarted by a loan, Doan looks like using a temporary switch to Germany as his shot in the arm. The 22-year-old arrived at Bielefeld on loan from PSV Eindhoven last summer, and is the ex-Gamba Osaka youngster's third European club having initially moved to Groningen.
Happy operating as a winger or wide attacker as well as the playmaker role Kagawa and Kamada fit into, Doan has shone in a struggling team as he bids to ensure he will have a place in Japan's Olympic squad for their gold-medal bid on home soil next summer.
"Ritsu is a clever winger with great pace," Arminia coach Uwe Neuhaus wrote on the club's website after Doan arrived. "He possesses qualities both in front of goal and in build-up play. That means he can be used flexibly in the offensive [set-up]."
Watch: Doan scores but Bayern win in Bielefeld
Doan only scored twice in 19 Eredivisie outings for PSV last season, but he already has an assist and a goal in the Bundesliga, and what a collector's item that strike was.
Not many get to net their first goal against one of the greatest goalkeepers of all time, but Doan did that when he struck against Manuel Neuer and Bayern Munich in a 4-1 defeat to the 2019/20 treble winners on Matchday 4.
"I was really pumped up," said Doan, who was nominated for October's Rookie of the Month award. "I'm happy to have scored against the best team in the world. I'll keep working hard to help my team win games."
Despite Doan's endeavours, three more defeats have followed for Arminia, though he did also register a first Bundesliga assist in the Matchday 5 loss to Wolfsburg. Labelled "a very exciting player" by former Bayern boss and current Manchester City manager Pep Guardiola, Doan could well join Kamada in living up to the stratospheric standards Kagawa set for Japanese playmakers in the Bundesliga.