Hajime Moriyasu's men pulled off one of tournament's upsets as they came from behind to stun Germany 2-1 in Wednesday's group opener courtesy of second-half goals from Ritsu Doan and former Arsenal forward Takuma Asano.
As for Costa Rica, they suffered their heaviest World Cup defeat as they were steamrolled 7-0 by Spain at the Al Thumama Stadium which saw their five-game unbeaten run come to an end.
Ahead of Sunday's meeting between Japan and Costa Rica, Sports Mole looks at how the squads of the two nations stack up against each other.
JAPAN
Most valuable player:
Daichi Kamada (£26m)
Overall squad value:
£133.4m
Most capped player:
Yuto Nagatomo (134)
Leading goalscorer:
Takumi Minamino (17)
Total caps:
930
Total goals:
88
Oldest player:
Eiji Kawashima (39)
Youngest player:
Takefusa Kubo (21)
Average age:
27.8
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Goalkeepers: Eiji Kawashima (Strasbourg), Shuichi Gonda (Shimizu S-Pulse), Daniel Schmidt (Sint-Truidense)
Defenders: Yuto Nagatomo (Tokyo FC), Maya Yoshida (Schalke 04), Hiroki Sakai (Urawa Red Diamonds), Shogo Taniguchi (Kawasaki Frontale), Miki Yamane (Kawasaki Frontale), Ko Itakura (Borussia Monchengladbach), Takehiro Tomiyasu (Arsenal), Hiroki Ito (Stuttgart)
Midfielders: Gaku Shibasaki (Leganes), Wataru Endo (Stuttgart), Junya Ito (Reims), Takumi Minamino (Monaco), Hidemasa Morita (Sporting Lisbon), Daichi Kamada (Eintracht Frankfurt), Yuki Soma (Nagoya Grampus), Kaoru Mitoma (Brighton & Hove Albion), Ritsu Doan (Freiburg), Ao Tanaka (Fortuna Dusseldorf), Takefusa Kubo (Real Sociedad)
Forwards: Takuma Asano (Bochum), Daizen Maeda (Celtic), Ayase Ueda (Cercle Brugge), Shuto Machino (Shonan Bellmare)
COSTA RICA
Most valuable player:
Keylor Navas (£4.3m)
Overall squad value:
£16.2m
Most capped player:
Celso Borges (156)
Leading goalscorer:
Bryan Ruiz (29)
Total caps:
1,169
Total goals:
127
Oldest player:
Bryan Ruiz (37)
Youngest player:
Jewison Bennette (18)
Average age:
27.2
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Goalkeepers: Keylor Navas (Paris Saint-Germain), Esteban Alvarado (Herediano), Patrick Sequeira (Lugo)
Defenders: Juan Pablo Vargas (Millonarios), Keysher Fuller (Herediano), Oscar Duarte (Al-Wehda), Bryan Oviedo (Real Salt Lake), Carlos Martinez (San Carlos), Francisco Calvo (Konyaspor), Kendall Waston (Saprissa), Ronald Matarrita (FC Cincinnati)
Midfielders: Daniel Chacon (Colorado Rapids 2), Celso Borges (Alajuelense), Jewison Bennette (Sunderland), Bryan Ruiz (Alajuelense), Gerson Torres (Herediano), Youstin Salas (Saprissa), Yeltsin Tejeda (Herediano), Brandon Aguilera (Nottingham Forest), Roan Wilson (Municipal Grecia), Douglas Lopez (Herediano), Anthony Hernandez (Puntarenas), Alvaro Zamora (Saprissa)
Forwards: Anthony Contreras (Herediano), Johan Venegas (Alajuelense), Joel Campbell (Leon)
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