Hi codename
Eurobet is an excellent casino/poker room/games/sportsbook available in 16 languages and operates through Brand Conversions on an open wallet rev share system.
In addition, I’d highly recommend 32Red – another of Brand Conversions merchants however we only have the landing pages, banners etc. available in English – however if you contact Lee or Kate directly I’m sure they can help you out with their Japanese site.
I hope this helps!
Cat