Outside, three people were stabbed and injured University of Tokyo on the first day of university entrance exams across Japan on Saturday.
Tokyo metropolitan police arrested a 17-year-old man at the crime scene and allegedly discovered a blood-stained kitchen knife.
As many as 530,000 students are expected to take national tests at several venues in Japan in two days.
Police said a teenager living and attending a school in Nagoya began stabbing students around 8:30 a.m. local time.
A 72-year-old man from Tokyo and two 18-year-olds from nearby Chiba Prefecture, who were on their way to the examination hall, were injured in the attack. None of them knew the suspect, police said.
Asahi The newspaper quoted an unknown source as saying the teenager had spoken out about his concerns about his poor grades during his alleged police confession.
All three victims of the knife attack were taken to hospital. Reports say two teenage victims were slightly injured, and a senior citizen had to undergo emergency surgery.
The National Center for University Entrance Exams – the body responsible for university entrance exams in Japan – has announced that teenagers who are due to take exams on Saturday will be able to take a make-up exam scheduled for last weekend. this month.
He also said he is considering other measures if they are unable to recover in time for a new exam date.