In fact the story's ambiguity is cleverly represented in its title "Kokuhaku" which in Japanese can be defined in two ways - not only to confess one's sins but also to confess one's love.
The story inventively starts in the middle with pretty Middle School teacher, Moriguchi Yuko (wonderfully realized by J-Dorama favorite Matsu Takako) announcing to her homeroom class that she is retiring. Of course, her apathetic and unruly students snidely celebrate her departure with laughter and high-fives. Yuko proceeds to then tell the students of the reason of her departure. In flashback we see the devastating and tragic loss of her five-year old daughter Manami (cute Ashida Mana), who drowned in the school's pool one night. While authorities label the death as an accidental drowning, Yuko discovers to her shock a more sinister explanation. Her daughter was intentionally drowned by two of her own students - the emotionally troubled "mama's boy" Shiomura Naoki (Fujiwara Kaoru) and the emotionally distant yet intellectually gifted Murakawa Shinya (Amami Juri), whom she just calls "Boy B" and "Boy A" respectively. Knowing that the authorities will not take any serious action given the fact that the two are just 13 year old minors, Yuko nonchalantly explains that she has already taken her revenge on the two by tainting their lunch milk with a syringe containing blood from her ex-husband who has HIV (she is also HIV Positive). Thus begins the story proper which examines the shattered lives of these two students as well as the tragic aftermath of this "confession" and of the cruel horrors that transpire from it. Like "Pandora's Box" Yuko's revenge unleashes an evil more darker than she could have ever imagined.
"Kokuhaku", based on the best selling 2008 Japanese novel of the same name by author Minato Kanae, is a blunt indignation of Japanese society and takes particular critical aim at its increasingly apathetic and narcissistic youth. Nakashima's screenplay drives this hard portrayal in by showing us that despite the unspeakable crime committed by the two students, the true evil lies in the resultant bullying and social ostracizing that results at the hands of their classmates. Despite all the information that has been distributed by the media on AIDS and how it is contracted, the ignorance and social stigma shown by the students is truly horrifying.
"Kokuhaku" is not a standard revenge movie and Nakashima masterfully deviates from the norm by focusing not on Yuko's rage but rather on the "monsters" that Yuko holds responsible for her daughter's death. As the movie unfolds, I unexpectedly found myself actually pitying these two poor souls as they were more-or-less victims themselves of unfortunate childhood traumas. While it doesn't excuse them of their crime, it does go far at explaining their motives and forces audiences to feel sympathy towards their plight.
The story's emotional impact is very much due to its extraordinary cast headed by the wonderful Matsu Takako (Long Vacation, Hero). I can understand now why Nakashima insisted on only having Matsu Takako portraying the part of the vengeful Yuko as she brings both a sense of tragic sadness and darkness to her role. Her quiet and understated portrayal is very effective (almost similar to Kaji Mieko's "Jyoshu Sasori" character) and if fact makes her character even more effective in a sense as it's almost like a slow, seething anger. Fujiwara Kaoru and Amami Juri are also quite good as the two juveniles. While Fujiwara tends to overplay his of part Naoki to the point of hysterics, Amami is the one who stands out as the intellectually brilliant Shin whose anti-social persona is just an affront to hide his need for his scientist mother's love and approval. Amami plays Shin as both a tragic and frightening character study. Hashimoto Ai is also great as Kitahara Mitsuki, Shin's only friend and kindred spirit who develops a compassion for the troubled youth and who foolishly believes that her love alone can change him. She is absolutely beautiful and is a definite star in the making. Kimura Yoshino is also wonderful as Naoki's devoted mother. Her performance is very unnerving and showed the unyielding love that her character had for her troubled son (a nice mirror to Matsu Takako's devotion to her character's daughter). Likable actor Okada Masami gives a good performance as the hopelessly optimistic and naive substitute teacher Yoshiteru Terada who attempts to reach out to both Naoki and Shin but whose general concern and good intentions soon become another destructive instrument in Yuko's revenge scheme. While only a small role Yamada Kinera's portrayal of Shin's estranged scientist mother was touching.
The cinematography compliments of Nakashima regular Ato Masakazu and Ozawa Atsushi are breathtaking and beautiful. They add to the emotional impact of the story and are absolutely stunning. Even the gory bits were beautifully rendered and shot (which seems almost strangely ironic).
"Kokuhaku" shatters the perpetual foreign stereotype of Japanese students as polite, docile, overly respectful and timid children and shows us that like in any other countries, some of today's youth have succumbed to the stresses of peer pressure, sense of self worth and purpose and have become selfish and disillusioned. The film is a cautionary tale of those dangers and also challenges the audience's notion and senses of morality. Are Yuko's a actions justified or has she become even more despicable, irresponsible and reckless as the students she holds response for her daughter's death? Does the ends really justify the means or does society really create its own monsters?