Kayako's Journal is a key element in both Ju-on and The Grudge film series. On its pages, Kayako wrote about her life and, as an adult and wife, about her secret love/obsession towards another man, which is eventually discovered by her husband Takeo.
Ju-on film seriesEdit
It is unclear how long Kayako had kept the journal, nor any further background information is given. Through the diary, her husband Takeo discovered her inner feelings for Shunsuke Kobayashi and murdered her in anger. His killings spawned a grudge curse in their house that would affect anyone that stepped inside, the first victim being Kobayashi himself. He entered the house and found the diary, reading Kayako's writings and realizing what exactly happened there. The journal, as well as some news reports on the Saeki murders, were received by Yoshimi Kitada, who after simply looking at it was instantly possessed by Kayako's spirit. The possessed Yoshimi killed her husband Hiroshi afterwards. Tatsuya later visited her and found the notebook, and was told that was "her diary". Rika found the journal inside the closet before Toshio and his cat surprised her. The journal was later found by Keisuke while shooting a television show in the house. He decided to leave it there, but the ghost of his crew's hairstylist Megumi passed it to him before vanishing.
Kayako was reborn through the pregnancy of Kyoko, an actress that had stepped inside the house, and as a little girl, killed her and walked out alone, carrying the diary.
The Begining of the EndEdit
In her journal, a lonely Kayako described her growing desire of having a child, and how a ghostly child once approached and returned to life inside her, becoming her son. Kayako's ghost left the journal to Yui, through which she was later briefly possessed. Yui's boyfriend Naoto found it and following her writings was led to the truth about the Saeki house murders and its curse.
The Grudge film seriesEdit
Kayako kept the diary since the age of 8. The journal revealed much of her background, as a child living in a small, rural village with her mother, Nakagawa Kawamata. Kayako was a vessel to her exorcisms, as Mrs. Kawamatta, an Itako, deposited the demons from others inside the little girl. As an adult and wife, Kayako wrote about her love/obsession towards an american professor, Peter Kirk, collecting from pictures to nail chips of his. Takeo later read about them in the jounal and murdered Kayako, their son Toshio and his pet cat Mar in anger, later hanging himself in the boy's bedroom (though it’s later revealed that Kayako killed him by hanging him with her hair).
The journal was found by an american social worker, Karen Davis, while she attended to the Williams family. Even though the book was found with Toshio in the closet, Karen correctly guessed that the writings belonged to a woman even without knowing the diary's owner, as the writing looked effeminate.
An american schoolgirl, Allison Fleming, found the journal while trapped inside the closet, moments before she was haunted by the resident ghosts. 2 years prior, Chinese journalist Eason took the diary from the house and, with the help of a specialist, discovered about her past with her Itako mother.
- Not noticed by her, the bloodied journal makes a subliminal apparition in Tomoka's appartment.
- Presumably, Kayako makes no mention to her sister Naoko on her journal, otherwise Aubrey and Eason could have contacted her and perhaps found their way to get rid of the curse.
- It is unclear if Naoko got the diary from Eason's apartment or from the Saeki house itself, since the journal supernaturally leaves and returns constantly throughout the Grudge films.
- The journal Naoko holds is slightly different from the one seen in previous films. Hers is clearly a hardcover notebook while Kayako's diary is a paperback notebook.
- The journal seems to curse whoever is reading it, as Mrs. Davis went through the pages and was instantly caught in the curse, killing her.
- If this deleted scene is to be taken as canon, then this means that the journal somehow traveled with her daughters’ belongings to California, and then returned to Japan to be discovered by Allison in the Saeki house.
- The pages of the book flipping themselves open is an intentional homage to The Evil Dead franchise, as the Necronomicon can also flip open its own pages. Sam Raimi, producer of The Grudge franchise, directed The Evil Dead Trilogy.
- The journal is one of two cursed objects in the franchise as a result of being owned by a ghost, the other being the Mr. Potato Head toy that Rose Morrison gave to Toshio.