The contents of this article are not for people moving out of Japan and shipping unaccompanied personal effects but for those residing overseas and shipping purchased goods or the like from Japan or shipping goods for other than personal use, such as selling/reselling.
When exporting goods from Japan, there must be a party that acts as the shipper/exporter. However, Japanese Customs Law stipulates that the entity acting as the shipper/exporter must have an address in Japan and, in the case of an individual, must have a residency in Japan.
Sometimes, individuals living outside Japan, i.e., without residencies in Japan, must transport goods purchased in Japan. There are two main cases. 1) A person traveling to Japan purchases products to send home for commercial/business use. 2) A person living abroad purchases goods from a seller in Japan but the seller cannot act as the exporter/shipper or a person purchases from multiple sellers and sends the items together as one consignment. This includes the cases of purchasing for personal use or business/commercial use. (Travelers may ship their purchased goods as unaccompanied personal effects if they are for personal use.)
For these two cases, Japan Customs will allow the export of your shipment if you assign a so-called “attorney for the customs procedure.” An attorney for the customs procedure is also referred to as a “customs manager” by Japan Customs. In Japanese, it is 事務管理人. An “attorney for the customs procedure” is a proxy who submits the export documents and, in some cases, can receive a refund (if any) on behalf of the exporter/importer of the goods whose residency is not in Japan.
The system of assigning an attorney for the customs procedure arose from the need for customs to contact a party in Japan in the event of a problem or to refund fees. It is basically a customs rule giving exporting rights to people living outside Japan, as otherwise they would not be qualified to export because of the residency requirement.
It takes time to get permission and a registered number for an “attorney for the customs procedure.” Therefore, once you know you need to ship something from Japan, you should make the arrangements immediately.
Ref: Customs Law Article 95