Japan and China use regular Western comma grouping for Latin numerals. The myriads are used only when using Japanese/Chinese numerals: １万円 for 10,000 yen, ２億円 for 200,000,000.

Thanks, I didn't know the formatting was following rules of Latin/Roman numerals. I remember having difficulties when learning to group numbers by 10k (with the -man suffix) during japanese courses more than a decade ago, I always assumed that was used everywhere.

Downvoted for a wrong guess? That's a bit harsh...