Returned mail is not only familiar with the postal route and postage of international mail, but also see the different postage machine propaganda stamps, and moreover see the foreign postal way of handling this type of mail. It is also possible to compare the different ways of foreign and domestic postal services in handling this kind of mail. This return envelope from Japan Post was mailed on December 31, 2022, and was sent by SAL and Mail for the blind. International Air Surface Mail, abbreviated as SAL, is international mail that uses the remaining capacity of international flights to transport across borders and is handled as surface mail in both the countries of origin and the destination. This is a type of combined rate mail, and the rate for this type of mail is very special. Among them, the mail for reading materials for the blind is free of charge, and only the air cost of ￥0.30 is charged. When Japan Post received the imported mail, it put a tracking slip on the back of the m...