Time Leap

is a Japanese light novel series written by Kyoichiro Takahata, with illustrations by Yu Kinutani. The series began publication on January 10, 1997 by ASCII Media Works under their Dengeki Bunko publishing imprint.

Synopsis
An ordinary high school girl, Shoka Kashima, realizes that one day she has lost her "memory of yesterday." And when she looked up her diary, she thought she wrote yesterday, and she had a sentence she didn't recognize. "You're confused right now ... talk to Wakamatsu-kun. You might think he's a cold person at first, but he's a reliable person." Kazuhiko Wakamatsu, who is rumored to be a talented person at school, Shoka Finds out that he has fallen into a kind of time movement phenomenon "time leap" and fights against the puzzle of time.