Suzuko's beloved cat and a little later the body of the Three-fingered man with a large wound in the chest in a charcoal oven near the estate. At the crime scene, Kindaichi solves the murder. Through questioning and the impeccable state of his diary, Kindaichi is able to conclude that Kenzo was obsessed with cleanliness. When he learned that his fiancée was no longer virgin, but that he could not dissolve the marriage without losing his face, he decided to kill her and then himself, making the act look like a double murder. In order to accomplish this, he attached the sword to a string of the koto, which led out through the shutter, a traditional Japanese ranma transom with a decorative gap above the sliding door, where it was attached to a water wheel. As the wheel turned, it drew out the sword that Kenzo used in the murder. Using a koto bridge, it was flung from the string into the snow, where witnesses later found it. The koto was played by Kenzo himself to mask the sounds the string made when it slid across the bamboo in the garden. Originally, Kenzo had planned to suggest the perpetrator's escape through the window, but since he forgot to open it, the murder seemed like an impossible crime. Also involved in the plan was his younger brother Saburo, who turns out to be the true mastermind behind the crime. After catching his brother preparing the mechanism, he became involved and decided to help him - on the one hand to get part of the life insurance, on the other to satisfy his urge for superiority as it is revealed he may be a psychopath. The crucial mechanism, according to Kindaichi, was probably inspired by the one in the Sherlock Holmes short story "The Riddle of Thor Bridge", in which a similar concept is used to make a suicide look like a murder. It was Saburo who edited the diary pages and glued the Three-fingered man's driving licence photo into Kenzo's diary. His injury was self-inflicted as he tried to demonstrate his mechanism again, only the severity of the cut was unintentional. The Three-fingered man was an uninvolved bus driver, who, according to the autopsy, died from exhaustion after a long hike near the estate. Kenzo discovered the corpse and cut off his hand so that he could fill the room with