Boku wa Mata, Kimi ni Sayonara no Kazu wo Miru

Also known as: 僕はまた、君にさよならの数を見る, ตัวเลขแห่งการจากลานำพาโชคชะตาแห่งรัก, 300 jours avec Toi, Hitung Mundur Perpisahanku Denganmu, 300 днів із тобою

by Kouhei Nagashii, Masaki Kiritomo

In that beautiful spring filled with cherry blossom petals, I met her. The girl with a bright and cheerful demeanor. "300", a cold-looking number floated above her head, and there, I know of the time where she will meet her demise. This is the story of my everyday life with her until the day we parted. (Source: Fujimi L Bunko, translated)