It is written in Japanese.
It is a book with hints to find a small shell (about 1mm).
A5 size, page 14. (There is no bonus for the bean book kit.)
The real thing is sold on another page.
Zineshell-miniature pop-up book (miniaturePopup.com)
This is the download sales page.
table of contents
1. Preparation for collection
2. Gathering ① Yuigahama (Kanagawa Prefecture)
3. Gathering ② Shigajima (Fukuoka Prefecture)
4. Gathering ③ Makuhari no Hama (Chiba Prefecture)
5. At home
6. Way of enjoying
7. At the end