Naomi Kawase came onto the scene in a major way with Suzaku (Moe No Suzaku, 1996), which after grabbing the International Critics prize at the Rotterdam Film Festival went on to win the Camera d'Or in Cannes that same year. That film, her debut as a feature director (she had made a number of shorts and co-directed This World (Utsushiyo, 1996) with Hirokazu Kore-eda), signalled what would eventually become her trademark style: semi-documentary fiction.
Kawase's films, while being works of fiction, incorporate elements of documentary filmmaking and vice versa. Not just in the use of the camera or the editing, but also in the naturalist performances by their often non-professional cast. Before Hotaru her films did however tend to lean towards one of the two elements: Suzaku was a fictional story about a family in rural Nara, while for instance Mangekyo (1999) was a documentary about two teenage girls' dreams of stardom (and Kawase's own exploration of what it means to be a filmmaker).
In Hotaru that line is completely blurred. There is a fictional storyline, certainly, but this love story is portrayed by two people who you doubt are actors. Not because their performances are bad, but because they don't seem to perform. They simply ARE these two young people who try to build a relationship as best they can, through hardships and tragedy. They don't show doubts, make love, argue, cry and make sacrifices because the screenplay requires them to, but, one feels, because this is their natural behavior towards each other. As if Naomi Kawase and her crew just happened to stumble upon them. What Nakamura and Nagasawa show here goes beyond acting and any director who can achieve this with his or her actors comes close to greatness.
Hotaru proves that there doesn't need to be a distinction between fiction and documentary. That searching to separate the two is not only a futile but above all pointless task. All that matters is the fact that here is deeply heartfelt and emotional cinema.