"Gukôroku" (or "Traces of Sin" in its English title) is a highly entertaining movie, with an incredible atmosphere, great pace and some food for thought that only falters a little bit in the end because of a tad overlong running time.
Satoshi Tsumabuki plays Tanaka, a journalist that decides to poke his nose in the old case of the murder of a family. His boss, knowing of his family situation (his sister is detained because of neglecting the care of her baby) decides to let him tackle the old case. Tanaka goes around meeting old friends from the family, like co-workers or university friends, little by little discovering a world of darkness, selfishness and an overall ugly image of a shallow and competitive culture. Tsumabuki does a great job in keeping his Tanaka a detached, curious viewer of the stories that unfold around him, his character just the medium that connects the viewer with the story. Everyone else does also a great job in creating characters that will make the viewer squirm and writhe in disgust, sadness or fear. The direction helps, keeping things simple and clear.
The tone of the movie is great, even though it is a little bit uneven in the time jumps and the moments it turns to Tanaka's relationship with his sister. The music and dark palette intensify the dread and dark tone of the movie. And when the twists appear, because there are a couple of them, they add to the movie (even if one or two are not particularly surprising).
"Gukôroku" is a great movie. Just be ready for a descent into human darkness.
