This idea is so close to being great though. It just needs a couple changes:

> Under the system, users can input these seven-digit codes on online shopping websites, and their addresses will automatically appear on the sites.

1. The site shouldn’t get your address at all. They print the code on the package, mail it to Japan Post, and Japan Post takes care of delivering it to you.

2. You should be able to generate new codes arbitrarily.

i.e. A service like Apple’s Hide My Email, but for physical mail.