"Third (3rd) Party Logistics (3PL for short)" generally refers to a company that proposes logistics reforms to shippers.
This refers to undertaking and carrying out comprehensive logistics operations.
Basically, 3PL (Third-Party Logistics) is considered a business in which a third party with expertise (sometimes the same as the carrier in Japan) plans, designs, and operates logistics from the shipper's perspective in order to resolve the inconveniences arising from the "conflict of interest" relationship between shippers and carriers.