Kawashima decides to kill Chiaki after suspecting she read his notes

Kawashima decides to kill Sanada Chiaki after noticing his open notebook beside his overnight bag and concluding that she may have read his plans. His suspicion is not confirmed, but he treats the possibility of exposure as decisive: the man who has just helped her now sees her as a witness who cannot be allowed to leave. The turn is especially stark because Sanada Chiaki has mistaken him for the unknown person who has taken her to hospital in the past.

Planning the Attack

Before meeting Sanada Chiaki, Kawashima had been converting the idea of murder into a practical scheme. He reasoned that the victim should be a woman with no close connection to him and considered how her disappearance might be reported, where an attack could take place, and how he could avoid identification. He rejected an outdoor location and a love hotel, whose staff or narrow entrance might create risks, and settled on a regular hotel where a reservation under a false name seemed less conspicuous.

The hotel choice was part of a broader effort to manage attention. Kawashima planned to compare several hotels in West Shinjuku, preferring a busy front desk and poor service because he expected guests to receive less scrutiny. At the Keio Plaza Hotel, he arrived by hotel bus from Shinjuku Station at 2:55 on a crowded Friday afternoon. Weddings and other events filled the lobby; the desk clerk barely noticed him, and no bellboy approached. He carried the tools and change of clothes in an ordinary overnight bag, and had prepared a regional newspaper as possible misdirection. The scene shows how much his plan depends on anticipating witnesses and controlling what they might remember.

The Encounter at the Keio Plaza Hotel

In the room, Sanada Chiaki appears in a confused and vulnerable state after harming herself. Kawashima intervenes, and she comes to believe that he is the person who has always made sure she reached a hospital. After she agrees to contact her office, he gathers her belongings, puts her Swiss Army knife back in her purse, and cleans the room. Her call gives her a plausible reason to leave work, while Kawashima helps her dress and accompanies her from the room.

That apparent rescue carries an imbalance of knowledge. Sanada Chiaki thinks she may have found the benevolent stranger she has long hoped to meet; Kawashima knows that his bag contains preparations for a planned killing. Her trust does not arise from certainty about who he is, but from the meaning she gives to his actions and to his willingness to help. For a time, their immediate aim is simply to get her out of the room and toward medical care.

The Notebook and the Decision

The change comes when Kawashima notices that his overnight bag has fallen on its side and his notebook is open beside it. He does not know whether Sanada Chiaki has read the pages. He nevertheless interprets the arrangement as evidence that she may have seen them, and imagines that, if she survives, she could tell someone about the client who planned such a crime. His fear of being exposed becomes a conclusion: he believes he has no choice but to kill her.

The decision also revives the purpose of the equipment he had brought. He is relieved that he has not discarded the ice pick and knife, which had remained in the bag despite the apparent change in the situation. A detail of disturbed luggage thus overturns the rescue scene: instead of treating Sanada Chiaki as someone to protect, he makes her the intended victim of the plan he had been rehearsing.

Aftermath and Significance

Sanada Chiaki later frees herself while Kawashima is unconscious. She finds the notebook and another package containing a large knife, then reads the notes through. She cannot tell whether they describe a crime he truly intended or fantasies, but she understands that he is not the devoted rescuer she had imagined. She does not call the police, anticipating a long and exhausting ordeal at the station; instead, she goes to bed with the notebook’s contents and her own uncertain interpretation on her mind.

The episode’s central reversal depends on the gap between intention and knowledge. Kawashima’s decision rests on an assumption, not on proof that Sanada Chiaki read the notebook; her discovery afterward does not resolve whether the plan was entirely real. Meanwhile, the precautions meant to keep his actions unnoticed cannot prevent a chance encounter from creating trust, nor can they make that trust safe. The notebook changes from a private instrument of planning into the object that exposes the danger he represents.