Gaikotsu Knife de Jump

is a Japanese light novel series written by Taro Achi, with illustrations by Sumi Miya. The series began publication on April 10, 2006 by ASCII Media Works under their Dengeki Bunko publishing imprint.

Synopsis
Nice to meet you. I'm Riorina Hayase. I am in the second year of junior high school. I'm embarrassed and only talk to my good friends, but I'm really curious about my classmate, Daichi Tengenji. I don't have the courage to confess, so I asked Megumi to go to the amusement park with six classmates. Of course, with Daichi-kun. First of all, I wish I could become a "little friend" from a "just classmate". When I was thinking about that, I had a small accident at a souvenir shop in an amusement park. Daichi-kun cut his hand with a knife. At that moment, the thing in front of me was distorted ...