4,000 undelivered mail. Japan Post haven’t announced. Sender may not know

It has been discovered that among the cases of mail handled by post offices across the country that was discarded or left unattended by postal workers and not delivered properly, there are cases that Japan Post has not made public. According to the company, among the undisclosed cases, there are cases where the sender of the mail could not be identified. For senders, there is a risk that the sender will not realize that the mail did not reach the recipient because it has not been made public.