JUM 2 was acquired from the estate of an individual who I helped clean archival scans for, many of which were shoujo themed works like so. I don't have much information on this particular group, but I can easily infer that these were college age shoujo fans as it appears to be a simple newsletter. There is a smattering of junior high students like so:

"Nice to meet you, my name is Nakamura Shune. I'm currently in the third year of junior high school, born June 8th, Gemini. My favorite artists are Oya Chiki, Tsubameo Moto, Ishimoto Hanako, and most of the people I know, Chiki Chaho, and Rinko-han. I like Bach's Fu, especially the Toccata and Fugue, and for the Piano piece, I like Liszt's "Mikanpanera". Queen is also good! I'll draw a picture like this. Flowers are my favorite. What a mess. Please send me letters and cuts."

This makes for the oldest doujin I own as its from 1975. JUM seems to be a unique pronunciation of 'jam' as there are mentions of marmalade in reference to the book itself. The editors seem to have been quite far apart and travel by train is mentioned in the beginning of the book. One editor hailed from Ibaraki while the other was from Shizuoka.

Members clearly were quite talented artists as many of these pieces or 'cuts' as they are called within the book are very gorgeous and were drawn to a small scale just for publishing.

"I'm looking for something to draw. The next JUM.2 topic will be to draw a caricature of a famous person in history. Please write the name of the person and the story behind it on the back of the card. Size 7×7cm (no extra). Here are a selection of a few hand-drawn cuts for example. I'll be selling (Jum 2) until January 15th next year, so please give them to me quickly for editing."

Members were also encouraged to reach out and correspond with one another and names and birthdates are given. This newsletter introduces new members. Many of the new members introduce themselves, leave their phone numbers, addresses etc. for correspondence. Given that this was pre-internet, this was one of the only ways to meet like minded friends.

The back cover appears to have been drawn by a Hiroshi Irie (入江洋), showing that males were a part of this particular group.