The Keio Line Halloween train attack
A moving express, a narrow passage between cars, and a lighter thrown at the crowd. Everyone survived; some never got over it.
- When
- October 31, 2021, about 7:55–7:58 p.m.
- Where
- Keio Line, Chofu, Tokyo
- Status
- Convicted
Content note stabbing, fire, mass attack. No graphic images.
In brief
Just before 8 p.m. on Halloween night 2021, a man in a purple suit stabbed a 72-year-old passenger in the chest on a Keio Line limited express heading toward central Tokyo through Chofu. He then went to another car, where passengers were crowding toward a narrow passage, sprayed about two and a half liters of lighter fluid toward them, lit a lighter and threw it. Part of the floor caught fire and black smoke filled the car as people pushed through into the next one. The train made an emergency stop at Kokuryo Station, where some passengers escaped through the windows. The stabbed man was gravely wounded and others were hurt, but no one died. Police arrested Kyota Hattori, 24, at the scene. In July 2023 the Tachikawa branch of the Tokyo District Court convicted him of attempted murder and arson and sentenced him to 23 years. Neither side appealed, and the sentence became final.
Turning pointThe court found that a slight difference in timing could have caused many deaths. Because no one died, the case was tried as attempted murder.
- Train
- A Keio Line limited express bound for Shinjuku
- Stabbed
- One passenger, a man of 72, gravely wounded in the chest
- Fire
- About 2.5 liters of lighter fluid sprayed and set alight on the floor of another car
- Deaths
- None; about 17 people were reported injured
- Convicted
- Kyota Hattori, attempted murder and arson, July 31, 2023
- Sentence
- 23 years; final in August 2023
Timeline
October 31, 2021About 7:55 p.m.
On a Keio Line express heading toward Shinjuku, a man in a purple suit stabs a 72-year-old passenger in the chest while the train is moving.
October 31, 2021
He moves toward the rear of the train, into a car where passengers are crowding toward the narrow passage, about 80 centimeters wide, into the next car.
October 31, 2021About 7:58 p.m.
He sprays about two and a half liters of lighter fluid toward them, lights a lighter and throws it. A patch of floor catches fire and black smoke rises as passengers struggle through the passage.
October 31, 2021
The train makes an emergency stop at Kokuryo Station, short of its usual position, so that the doors and platform don't line up. Passengers leave through doors and windows.
October 31, 2021
Police arrest Kyota Hattori, 24, at the scene.
June 26, 2023
At trial he admits the stabbing and the fire but denies intending to kill anyone with the fire.
July 31, 2023
The court convicts him of attempted murder and arson and sentences him to 23 years, calling it an indiscriminate crime with a selfish motive. Prosecutors had asked for 25.
August 14, 2023
With no appeal from either side, the sentence becomes final.
The full story
A Halloween night train
On the evening of October 31, 2021, a Keio Line limited express was carrying passengers toward Shinjuku through Chofu, in Tokyo’s western suburbs. Just before 8 p.m., a man in a purple suit and green shirt pulled out a knife and stabbed a 72-year-old man in the chest while the train was moving.
The passage
The attacker moved on through the train. In another car, passengers who had seen what happened were crowding toward the narrow passage, about 80 centimeters wide, that led to the next car. He sprayed about two and a half liters of lighter fluid toward them, lit a lighter and threw it. A patch of the floor caught fire and black smoke rose as people stumbled and pushed through into the next car.
The train made an emergency stop at Kokuryo Station. It stopped short of its usual position, so the doors didn’t line up with the platform, and some passengers climbed out through the windows.
No one died
The man who was stabbed was gravely wounded. Others were injured, many of them while escaping. No one was killed. Police arrested Kyota Hattori, 24, at the scene. He told them he had wanted to kill people so he would be sentenced to death.
The sentence
At trial in 2023, Hattori admitted the stabbing and the fire but denied intending to kill anyone with the fire. The Tachikawa branch of the Tokyo District Court disagreed. It convicted him of attempted murder and arson, found that a slight difference in timing could have led to many deaths, and sentenced him to 23 years. Neither side appealed.
Getting off the train didn’t end it for the people on board. The man who was stabbed told the court he could no longer work. A young woman who escaped said she could no longer ride trains.
What the video couldn't include
A small fire, a real danger
The fire burned a small patch of floor, about 0.09 square meters. None of the ten passengers named in the arson counts suffered burns or had their clothing catch fire, but the court found they had been in real danger.
What he said he wanted
Hattori told police he wanted to kill people so he would be sentenced to death, and said he had been influenced by a stabbing on another Tokyo train line that August. Prosecutors said he chose a limited express because it made fewer stops.
The costume
Because of his purple suit and green shirt, news reports around the world compared him to the Joker. This page does not use the nickname as his name.
Injury counts differ
Police and Reuters reported 17 people injured; a Fire and Disaster Management Agency preliminary report counted 18. Most injuries were minor and many came during the escape rather than from the attack itself.
After
The man who was stabbed told the court he could no longer work. A 21-year-old woman who escaped said she could no longer ride trains.
The video and the record
The episode tells this case in about 1 minutes with illustrated recreations. Here is how its key moments line up with what is documented.
A man in a purple suit stabbed a seventy-two-year-old passenger on a Tokyo express train
Documented
From the court judgment, which anonymizes the victim.
He sprayed lighter fluid toward them, lit a lighter, and threw it
Documented
About 2.5 liters, according to the judgment.
Some passengers climbed out through the windows
Documented
The train stopped short of its marks at Kokuryo, according to the rail operator's report.
No one died
Documented
Reported injury totals range from 17 to 18; most injuries were minor.
The stabbed man told the court he could no longer work. A woman who escaped said she could no longer ride trains
Documented
Victim-impact testimony reported by FRIDAY Digital. Both are anonymous.
The train, the passage, the floor fire, the windows
Reconstruction
AI-generated illustrations. The fire is shown as a small floor fire, as the court found; passenger video is not reproduced.
What the four marks mean
- Documented
- Shown as it is recorded in court filings, police statements, or consistent reporting.
- Reconstruction
- A reasonable visual recreation of a documented event. The event happened; the image is illustrative.
- Compressed
- Real events shortened, merged, or reordered to fit the runtime.
- Dramatized
- A storytelling choice (framing, wording, emphasis) that the record does not establish.
Sources
- [1]Courts in JapanJudgment, Tachikawa Branch of the Tokyo District CourtIn Japanese. Names of the defendant, victims and stations are anonymized.
- [2]Keio Corporation, published by Japan's Ministry of Land, Infrastructure, Transport and TourismIncident report on the October 31, 2021 Keio Line attackIn Japanese.
- [3]Fire and Disaster Management AgencyPreliminary report on the Keio Line train fireIn Japanese.
- [4]Reuters, via NBC News“Man in Joker costume injures 17 people on Tokyo train”
- [5]Associated Press, via France 24“Man dressed as Joker injures 17 in knife, fire attack on Tokyo train”
- [6]Associated Press, via Yahoo News“Japanese court sentences 'Joker' to 23 years for stabbing passenger, setting a fire on a Tokyo train”
- [7]Kyodo News, via Khaosod English“Halloween 'Joker' Attacker Gets 23 Years for Tokyo Train Stabbing, Fire”
- [8]NikkeiKeio Line stabbing: defendant sentenced to 23 yearsIn Japanese.
- [9]The Japan Times“Tokyo 'Joker' train attacker pleads not guilty to murder intent over arson”
- [10]FRIDAY Digital (Kodansha)Courtroom account and finalized 23-year sentence in the Keio Line caseIn Japanese.
- [11]Nikkan SportsReport on the finalized sentenceIn Japanese.
VerifiedKey facts in this file were checked against multiple consistent reports and first-person or official accounts. Last reviewed October 6, 2026. How we check cases
