When you move, let's submit a move notice to the post office yourself.

Everyone in Japan,
When you move, let's notify the post office of your move.
Even if important documents arrive at the previous address, they will be sent to the new address for one year.

Post office URL
Relocation / transfer service
https://www.post.japanpost.jp/service/tenkyo/

You can also apply for a move notice from the Internet.