Foreign mail day

Today, and January 8th annually, is Foreign Mail Day 外国郵便の日 in Japan, what we might call "International Mail" more naturally in English. The date, January 8th, is because on this day in 1875, the Yokohama Post Office officially began handling foreign mail.

Before this change, international mail services in Japan were operated by the American Post Office located in Yokohama’s foreign settlement. When that office was closed, the responsibility shifted to the Japanese government, marking a major step toward establishing Japan’s own modern postal system and furthering Japan's growing connection with the world. 

As far as I am aware, you can still see a commemorative plaque at the Yokohama Port Post Office honoring this milestone. Have you ever seen it?