Clothing and shoes size system is different in many countries. Please, understand that all tables have only informative characters and there can be the difference between manufacturers and brands, too.
There is official information about Japanese clothing and shoes sizes system. http://web.ita.doc.gov/tacgi/overseasnew.nsf/annexview/Japanese+Size+Charts
Please visit those sites, if you want an international comparison and chart tables of shirt, shoes, bra, skirt, jeans, hats, rings, etc.
If you have any question about your clothes and shoes, please ask us directly.