Based on an award winning light novel:

One day, I – a high schooler – found a paperback in the hospital. The “Disease Coexistence Journal” was its title. It was a diary that my classmate, Sakura Yamauchi, had written in secret. Inside, it was written that due to her pancreatic disease, her days were numbered. And thus, I coincidentally went from Just-a-Classmate to a Secret-Knowing-Classmate. It was as if I were being drawn to her, who was my polar opposite. However, the world presented the girl that was already suffering from an illness with an equally cruel reality…

List of Awards (Light Novel):

“Bestsellers 2016 (Overall) by NIPPAN” – 4th Place

“Bestsellers 2016 (Paperback Fiction) by NIPPAN” – 1st Place

“Bestsellers 2016 (Overall) by TOHAN” – 5th Place

“Bestsellers 2016 (Literary Books) by TOHAN” – 1st Place

“Bookstore Grand Prix 2016” – 2nd Place

“DA VINCI BOOK OF THE YEAR 2015” – 2nd Place

“Bestsellers 2015 (Literary Books) by TOHAN” – 6th Place

As of May 2017, this book has sold over 1.2 million copies.