Tenjite Koi to Iki

One day, high school teacher Yoshitake finds a 60's era paper left in the school's old building. Written there are the names Yousuke Haruoki, writer of a short story, and Mikumo Sakagami, the short story's main character. Through an array of strange coincidences, Yoshitake and his colleague, Yahiro, begin to have the strangest hunch: that Haruoki and Sakagami were their past lives.

(Source: Fantasista Inc.)