1 rittoru no namida (1リットルの涙, Ichi rittoru no namida?, lit. "1 Litre of Tears"; also called A Diary with Tears or A Diary of Tears) is a Japanese television drama for Fuji Television about a girl who was diagnosed with an incurable degenerative disease at 15, but was able to continue her life until her death at the age of 25.
On April 5, 2007, Fuji Television aired a three hour special of the series set half a year after Aya's death and focuses on Haruto Asō, who has now become a doctor at the same hospital Aya was treated in and Ako Ikeuchi, Aya's younger sister who is a nurse in training. Haruto meets a 14-year-old female patient, Mizuki, who was bullied in school because of her disease, the same one that Aya had. Because of the bullying at school, Mizuki-chan decides not to receive therapy of any sort that would make her better, because she has lost her will to live. Haruto remembers how Aya fought her illness and lived her life with her disease; therefore, he offers support to his patient. Aya reappears in the episode using a number of flashbacks from the series and in new scenes.
Asae Onishi starred in the 2004 movie version of the same title.
Indonesian Production House SinemArt's drama, titled Buku Harian Nayla (Nayla's Diary), plagiarizes 1 Litre of Tears. The series bears some striking resemblances, like the name "Aya" being replaced with "Nayla" (Chelsea Olivia) and Moses (Ralph Glenn Alinskie) in place of Asou. The series aired in RCTI as a special Christmas series. The comparison between the two series have been discussed by the show's audience. The scenario was written by Serena Luna (or sometimes called Chevyra Edenia).