Hi @Ryuuen, thank you for the post.
As it is mentioned in the How to/What to report on this topic on the first post; When making decisions for Postal Monitor, Postcrossing also takes into consideration the statistics and reports from its members. Japan is one of these cases.
*In addition to the official announcement from the postal agency, our Postal monitor is based on the actual reports from Postcrossing members on their returned/unaccepted postcards.
e.g. Japan, South Korea (surface only = suspended)
Overall global mail traffic and lockdown trends are being monitored, tested and checked if more destination countries could be added.
To avoid returned or rejected postcards at post offices for the 10585 members in Japan, Postcrossing will ease out the suspended routes carefully. That’s my understanding.