Number of Japanese fighters combined on the resumes of Fedor, Nog, and CC: 30
The 3 HW GOATs have a combined 30 fights against opponents from a country
Ye, among those:
Kazuyuki Fujita - beat UFC champions Mark Kerr & Ken Shamrock
Hidehiko Yoshida - beat UFC champions Don Frye, Maurice Smith, & UFC interim title challenger Mark Hunt
Kazushi Sakuraba - beat UFC champions: Rampage, K. Shamrock, Belfort, Randleman, Mezger, Royce Gracie
Enson Inoue - beat UFC champion Randy Couture
Satoshi Ishii - beat UFC champion Tim Sylvia, and UFC title challengers Pedro Rizzo & Monson
Kyoshi Tamura - beat UFC champions Maurice Smith, Dave Menne, and UFC title challenger Jeremy Horn and UFC tournament runner up Patrick Smith
Tsuyoshi Koshaka - beat UFC champion Maurice Smith and UFC title challenegers Kimo Leopoldo and Pete Williams
Ikuhisa Minowa - beat UFC champion Don Frye, and UFC title challenger Kimo Leopoldo
Hiromitsu Kanehara - beat UFC champion Dave Menne & UFC title challenger Jeremy Horn
Yoshihisa Yamamoto - beat UFC champion Mark Kerr
Ryushi Yanagisawa - beat UFC champion Oleg Taktarov, and UFC tournament runner-up Paul Varleans
Naoya Ogawa - beat UFC tournament runner-up Gary Goodridge
Sane Kikuta - beat UFC title challenger Jeremy Horn
So, those Japs have 19 wins vs UFC champions and 12 UFC title challengers and tournament runner-ups.
In those times Japan was center of combat world with 3 major MMA organizations: Pride, Pancrase, RINGS + K-1.
Of course there were plenty of Japanese fighters fighting in front of their audience in their organisations which had the strongest competition in the world and which paid the best in the world, and in rules that are better suited for their traditional martial arts like judo and jiu jitsu.