Ring of Curse aka Gomenasai (2011) – Mari Asato.

A pretty popular student Yuka Hidaka (Airi Suzuki) and her fellow bullying companions desperately seek a way to protect themselves from a curse that victimised classmate Hinako Kurohane (Miyabi Natsuyaki) imbedded within the text of her school play. What commences as a routine 'ostracize the gifted outsider' narrative thrillingly takes a far more disturbing jaunt into the macabre when the solitary, unfairly beleaguered Kurohane unleashes her poisoned prose upon her abusers! Asato's low budget, enjoyably creepy high school J-Horror gem features girl band Buono! and enjoys a number of deliciously spooksome moments! It would certainly appear that wielded by the demonic digits of Kurohane the pen is far mightier than the sword! The performances are fine, the scares are fun, but the film's resounding star is the truly tragic figure of Ms. Kurohane, and the terribly melancholic revelations within her diary.