I bought this in Korea. It doesn't seem to be a Japanese standard, as I couldn't find the same product in Japan. It's labeled as 2XL, but it fits quite tight on me, and I'm 180cm and 75kg. Therefore, I believe the sizing runs small. I'm listing it as equivalent to a Japanese L size. Only tried it on indoors. I haven't been able to authenticate it. Returns are not accepted after purchase, so please make your decision carefully before buying.