Here is a snap of the Japan Post Office logo, on our local post office’s door. The sign you will see for the PO, or “yuubin kyoku” is a red T with two horizontal bars on the top.
Lately, the PO has been marketing hard to better compete with private services - they have come round the office a couple of times to try to hawk their services. Much better than the PO of old, which was positively Imperious. (Cue Death Star Music)