Shijima Mei's Yorishiro

Shijima's yorishiro is a sketchbook, which is the same one her human counterpart, Mei, sketched the tower in.

Appearance
The yorishiro is a basic, coverless sketchbook with dark leaf book binders and A4 sized papers. Most of the contents in the sketchbook are not shown, but on one page there is a sketch of a tower that she was required to draw for the final exam of her art program.

After the sketchbook became a yorishiro, a black seal with red japanese letters spelling "封" or "seal" when translated to english was sticked on the middle of the first page.

History
The sketchbook was owned by the original human Shijima Mei, where she sketches her last pieces of art before her death. Most importantly, she drew the tower, which was made for her art program, and later was used as Shijima's residence in the Picture Perfect Arc. She imagined herself to be healthy and happy, drawing pictures; "I want to at least be happy inside my pictures, after all." She makes the Shijima inside the picture promise to draw for her until she gets better, but unfortunately that never happened, and she passed away later, after finishing the art piece of the tower.

After her death, the rumours around the picture of the tower earned Shijima a place in the Seven Mysteries, where her yorishiro became the sketchbook, and her boundary became the atelier tower.