JSDF Officer Arrested in Akasaka Live House Attack—Friends Say He Hid a Dark Side

By bicycle, a distance of 40 kilometers from Nerima Ward to Akasaka

on November 16, just before a live performance. On November 22, the Metropolitan Police Department’s First Investigation Division arrested Yoichiro Otsu (43) on suspicion of attempted murder.

Otsu, an active member of the Japan Ground Self-Defense Force, told police during questioning:

“I had an extramarital affair with the woman for nine years.”

“I hid the fact that I had a family while dating her.”

“I met the victim on social media nine years ago, which led to our relationship.”

A reporter from a national newspaper’s social affairs desk explained the events of the day:

“At around 10:25 a.m. on November 16, emergency services received a call reporting, ‘A woman is being stabbed by a man in a black hat and is bleeding.’ The live house where the incident occurred is in the basement, and the woman was apparently attacked while waiting for the venue to open.

Otsu traveled by bicycle from his home in Nerima Ward to Akasaka, a distance of 40 kilometers, and security cameras confirm that he was loitering around the area at least two hours before the attack, seemingly looking for the woman. Before the attack, he reportedly marked a poster promoting the woman’s performance with a black ‘X,’ the attack itself lasted only about 30 seconds, and he wore gloves and plastic bags on his feet—indicating a premeditated act with intent to kill.”

Security cameras also captured Otsu riding his bicycle after the attack, wearing a black hat pulled low and a mask to conceal his face.

A nearby business owner expressed his fear:

“Akasaka is usually a quiet shopping street on Sundays. But that day, the sirens never stopped. When I went outside, multiple ambulances and police cars had arrived, and the police had set up barriers. A friend who had come to see what was happening told me, ‘It seems a woman was stabbed,’ and that the suspect was a man dressed all in black. Checking our security camera, we saw him. Later, detectives came and took a copy of the footage as evidence.”

The woman’s injuries reached her internal organs, and her kidney was removed.

After the attack, Otsu returned to his workplace at the Asaka garrison and continued his duties the next day as if nothing had happened.

According to the Japan Ground Self-Defense Force, Otsu joined in 2003 and was assigned to Asaka garrison. Sources say he was transferred to the Hachinohe garrison in Aomori Prefecture around 2018 and returned to Asaka garrison in 2024.

Otsu’s hobby was running, and he focused on building his physical fitness

Since around March last year, Otsu had been assigned to the 1st Engineering Battalion at the Asaka garrison, managing heavy machinery and equipment, and he sometimes prepared meals.

An old acquaintance of Otsu revealed:

“Otsu was born in Hitachi-Ōmiya City, Ibaraki Prefecture. After graduating from local elementary and junior high schools, he attended a prefectural high school and joined the Japan Ground Self-Defense Force immediately after graduation. The Otsu family was a well-known landowning family in the area, considered a prominent household. His father worked at the Ibaraki Prefectural Government, and his mother was a teacher. Perhaps because of this, he grew up in a highly education-focused household, with limited playtime, and he wasn’t even allowed to buy popular games at the time.”

The acquaintance added,

“His personality was rather quiet, and he had an unremarkable presence. He wasn’t the type to actively make friends.”

Otsu reportedly married his current wife before being assigned to Aomori Prefecture. In 2019, he took out a loan of about 47 million yen to purchase a detached house in Nerima Ward. The acquaintance continued:

“I remember him being excited when he talked about buying the house. I heard he drove from Aomori to Tokyo to sign the contract, so everyone thought he had a happy family life.”

After finishing his assignment in Aomori and returning to the Asaka garrison, he commuted by bicycle from his home to the base.

Friends recalled an image of him as a devoted family man. However, neighbors who knew him described a different side:

“He probably wasn’t very close to his children. While the children attended local events, he rarely showed up, and even when he did, he didn’t interact much with his family—he seemed to keep to himself. He likely didn’t participate much in family gatherings.”

A reporter from the social affairs desk added,

“Otsu told people that his hobby was running, and he worked hard on physical fitness. He was considered serious at work, even refraining from drinking alcohol if he had an early shift the next day. However, he reportedly told friends that he couldn’t return home often due to frequent night duties. Those familiar with the Self-Defense Force later realized this was false, as his unit’s schedule wasn’t that demanding.”

It has been almost 20 days since Otsu’s arrest. He still partially denies the charges, claiming,

“I didn’t go to Akasaka,”

but the truth remains uncertain.