Number-kun was the mascot of the Japanese postal service from the years 1966 to 1996.
He was originally created to promote the new regular post system, used for sending letters and envelopes.
Starting in 1967, he was repurposed to instead be the mascot of the brand new postal codes that would be introduced the next year. His job was to promote people to actually use postcodes when sending their mail.
Mail would become so much easier on the workers and faster for the people relying on it, but everyone needed a push to start using them!
