We will have a spot sale of fan fictions such as doujinshi or goods based on "Sound! Euphonium" and "Uji".
What is Doujinshi?
Doujinshi is the Japanese term for self-published works.
It is a booklet created by members of the same hobby.
What is the spot sale?
It is an event to be held in Japan to distribute doujinshi.
The typical example is Comic Market (Comiket).
What is Circle?
It is an organization formed to create doujinshi.
A number of such groups consist of a single artist and they are sometimes called personal circles.