Japan has the most Major Titles in Boxing. America is #2.

[famicommander]

I don't really care where a fighter is from, but to me there's a difference between a champion and a belt holder. There is only one champion per division.

The actual champions
Heavyweight - Usyk (Ukraine)
Cruiserweight - Opetaia (Australia)
Light Heavyweight - Beterbiev (Canada/Russia)
Super Middleweight - Canelo (Mexico)
Middleweight - vacant since Canelo moved up
Super Welterweight - Charlo (USA) (soon to be vacant if he doesn't defend it)
Welterweight - Crawford (USA) (soon to be vacant)
Super Lightweight - Lopez (USA)
Lightweight - vacant since Haney moved up
Super Featherweight - vacant since Stevenson moved up
Featherweight - vacant since Pacquiao moved up in 2005
Super Bantamweight - Inoue (Japan)
Bantamweight - vacant since Inoue moved up
Super Flyweight - Estrada (Mexico)
Flyweight - vacant since Chocolatito moved up in 2016
Light flyweight - Teraji (Japan)
Strawweight - vacant since Ricardo Lopez moved up in 1999

So the US technically leads with 3 champions, but soon Crawford will abdicate his welterweight crown and Charlo hasn't defended his super welterweight crown in a long time. Needs to announce a fight by the end of the year or abdicate.

Japan and Mexico are strong with 2 champions each, but soon Estrada will defend against the American Rodriguez.

Australia and Ukraine with 1 champion each, Canada and Russia sharing credit for Beterbiev.

[Inoue Body Shot]

Interesting to see that Japan is having that much success in Boxing.

[famicommander]

Interesting to see that Japan is having that much success in Boxing.

It's not that surprising, in terms of all time historical belt holders Japan is a top 5 nation. These numbers were as of earlier this year:
1. USA (455)
2. Mexico (153)
3. UK (101)
4. Japan (85)
5. Puerto Rico (48) [technically part of the USA, but for boxing/sports purposes stands as its own nation]
6. Thailand (46)
6. South Korea (46)
8. Argentina (43)
9. Philippines (40)
10. Colombia (36)

Martial arts and combat sports are part of the culture in Japan. Boxing, Judo, Karate, Sumo, Jujutsu, kickboxing, MMA, even professional wrestling are all quite popular there compared to most other countries.