Translation guide
A private mailbox at a post office, used for receiving mail. In Japan, this is commonly called a 私書箱 (ししょばこ).
post office box
A rented mailbox at a post office for receiving mail.
The standard term for a post office box in Japan. Used in addresses and official contexts.
I'd like to rent a post office box.
Please send it to my post office box.
A more formal or full term, literally 'postal private box'. Often seen in official documents.
Please fill in your post office box number.
How to write a post office box in a Japanese address.
Standard address format for a post office box. The postal code and city are followed by 私書箱 and the box number.
P.O. Box 123, Chiyoda-ku, Tokyo 100-0001