-Issui pottery WEB
Issuigama is a pottery studio located in Okinawa Prefecture, the southernmost island of Japan.
Japan has the history of ceramic art that starts with Jomon ware (straw-rope pattern pottery), which is classified as one of the oldest in the world ceramic history.
And there were ceramic teacups and tea containers which were regarded as supreme treasures in the art of tea ceremony around Warring States period (of Japanese history, approx. 1467-1573 CE).
There was also a small earthenware pot, which was a prize given to SAMURAI for having fought in battles risking their lives.
It had no pattern, nothing on it.
Just a small, rustic pot made by an anonymous potter.

What the Japanese have seen inside the small earthenware pot?

Through my daily work, I am thinking something like that.