Aishima Shizuo: A Victim of Japan’s “Hostage Justice” System

Aishima Shizuo: A Victim of Japan’s “Hostage Justice” System

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Aishima Shizuo
Picture: Canva
Tokyo police and prosecutors falsely accused him of exporting biological weapons to China. How Aishima Shizuo died an innocent man in prison.

What killed him? Was it the cancer? Or was it the Japanese justice system?

Police arrested Aishima Shizuo on chemical weapons charges in March 2020. He died eleven months later at age 72. During that time, he was diagnosed with cancer, denied bail eight times, and underwent chemotherapy. All the while, he maintained his innocence.

Months after his death, prosecutors dropped the charges. Here’s how police fabricated evidence against Aishima, how prosecutors kept him in jail, and how tone-deaf officials are still refusing to apologize as they appeal against his family’s lawsuit.  

From retirement by Mt. Fuji to detainment

Picture: よっちゃん必撮仕事人 / PIXTA(ピクスタ)

“When it’s just the two of us, let’s move to Mt. Fuji and grow vegetables. I want to build a hut and do bamboo crafting.”

That’s what Aishima told his wife as he was closing his career chapter, ready for retirement.

Aishima was an engineer for 35 years at Ohkawara Kakohki, an engineering company based in Yokohama. The company specializes in spraying and drying technology. Their spray dryer was top of its class in the Japanese market. (These spray dryers turn liquid into powder. They’re responsible for turning coffee into that powder you mix with water to make instant coffee.)

Aishima loved developing spray dryers as much as he enjoyed making radios and amps as a kid. He wanted to retire but would miss his job.


Luckily for him, Ohkawara Kakohki’s research laboratory was at the foot of Mt. Fuji.

In 2018, Aishima and his wife moved to Fujinoimiya City. There, he stayed with the company as the laboratory’s advisor. He bought a house with a great view of Mt. Fuji.

He had his dream job and dream retirement.

It wasn’t all dreams though. A nightmare would start soon. And he would die in it.

291 interviews

Spray dryer
A spray dryer of the type developed by Ohkawara Kakohki. (Picture: Tottori Institute of Industrial Technology)

In 2018, the same year Aishima moved to the laboratory, the Tokyo Metropolitan Police Department began investigating Ohkawara Kakohki. The company was under suspicion for illegally exporting biological weapons, aka spray dyers with lethal potential, to China.

Spray dryers are in fact capable of harming more than your coffee standards. It’s possible to repurpose the equipment to make biological weapons. To export spray dryers, manufacturers need authorization from the Ministry of Economy, Trade, and Industry.

Aishima, along with 50 others from Ohkawara Kakohki cooperated with the investigation. The police conducted 291 interviews. Aishima alone gave 20.

For every interview, all of which were voluntary, Aishima had to travel from Fujinomiya to the Harajuku police office. Transportation options vary but the journey can stretch more than eight hours. Aishima made that trip every month to defend his work and innocence.

But the police had their own story. Not to defend. To fabricate.

Swept away to jail

“Put out some tea for the policemen.”

Aishima asked his wife to bring out refreshments for the five cops who had shown up on his doorstep without warning on a Wednesday morning.

“You need to come with us,” they told him.

Aishima’s hospitality made it all the more heartbreaking for his wife. She had to watch a good man climb into a police car.

The next morning, on March 12th, Aishima’s wife turned on the TV. Her husband was on the screen.

In handcuffs.

Bail requests denied, denied, and denied

“I don’t know.”

For any question, Aishima always had an answer, his wife says. But when she asked him how he got here––here as in the Tokyo Detention House’s visitation room wearing a detainee uniform––he didn’t have one.

When he wasn’t in the visitation room, Aishima would be in his cell. A 5.4 square meter room. That’s exactly three tatami mats. Close by, Ohkawara Kakohki’s CEO Ohkawara Masaaki, and board director Shimada Junji had cells of their own.

In Japan, police can hold a suspect without charges for 22 days. They can then re-arrest the suspect and extend the clock. After prosecutors have filed charges, they can then ask a court to hold a suspect without bail on charges they might flee or destroy evidence.

The result is that the state can hold those accused of crimes almost indefinitely. The most famous case is perhaps Carlos Ghosn, whom authorities held for 108 days without bail. In a separate case, authorities held another set of defendants, Kagoike Yasunori and his wife Junko, a full 10 months on charges of fraud.

Recently, in Osaka, police held a man suspected of harassment for 40 days before admitting they had the wrong person.

Attorney Gou Takada represented Aishima, Ohkawara, and Shimada. Takada filed for his client’s bail three times, all denied.

Then Aishima’s health began declining.

The Tokyo District Court’s reasoning for denying bail was based on prosecutors’ belief that the accused would destroy evidence. In response, Takada pleaded that his clients would not engage in any contact with involved parties and access company property. In addition, he promised to submit all three men’s call and email records.

Still, in a letter from the prosecutor’s office that cited Carlos Ghosn’s escape, the terms by Takada were deemed too risky and insufficient to permit bail.

Hostage game for confession prize

Aishima swore on his innocence. He refused to give a false confession, even when his wife thought it was the best option. Sadly, Japan’s justice system used that unwavering faith in his innocence against him.

Japan’s Supreme Court compiled data from 2021 showing a correlation between claims of innocence and denial of bail. Whereas 26.3% of detainees who confessed were granted bail, only 12.2% of those who denied any guilt were let out.

“If they admit wrongdoing, they can be set free very quickly. If they don’t, they can stay behind bars awaiting trial for six months or even up to a year,” says Peter Landers, WSJ Tokyo.

This may appear as an outright violation of the legal principle that you’re innocent until proven guilty. Japanese courts say otherwise.

There is a judge in charge of deciding if the accused gets bail or not. That’s separate from the judge who decides if the accused is guilty or not, says an anonymous Japanese judge.

“I feel sorry for people who are detained for long periods under false allegations. But if you’re going to insist that you’re falsely accused, you need to put up with the fact that it’s going to take a long time.”

This tactic of using extensive imprisonment as a means to force confessions is called “hostage-justice” or hitojichi-shihō (人質司法) in Japanese.

Prosecutors made Aishima a hostage to prevent him from destroying evidence. But the cancer was already destroying him.

What killed Aishima?

On September 29th, Takada requested bail for the fourth time. Aishima’s life was in danger. He was anemic and had already received a 400cc blood transfusion. His stool was black. His intestines were bleeding out.

Bail? Denied.

The detention facility’s doctor conducted an endoscopy exam on Aishima and found stomach cancer about a week later. Over a week after that, Aishima was permitted a temporary suspension of his detention lasting eight hours to go to the hospital. There, he was diagnosed with advanced gastric cancer.

At this point, Aishima was in such bad shape that he couldn’t walk on his own. Still, he returned to his cell that night, with no clue of when or if he will receive treatment.

After denying another request for bail, the judge gave Aishima a second temporary suspension to undergo chemotherapy in November.

“I was about to get murdered in prison,” Aishima told his wife at the hospital.

Innocent, but gone

Picture: metamorworks / PIXTA(ピクスタ)

2020 came and went. Chemotherapy wouldn’t do anything anymore. The doctors could only keep Aishima as comfortable for the time he had left.

Takada, frustrated but determined, requested bail again. This time, for the first time, the court approved.

That was February 4th. Aishima took his last breath three days later.

Had he lived for another five months, Aishima would have seen the prosecutors drop charges just four days before the first trial.

“After reinvestigating the case, we found the possibility that (the case) does not apply to the regulations for exports….We can’t explain our legal interpretation to the judges. There’s a risk that the judges will think we intentionally bent (the facts) to build our case.”

Tokyo District Prosecution Office

Unfinished hut

Aishima’s family and Ohkawara Kakohki sued the government and Tokyo in a civil court for ¥570,000,000 (USD 3,910,604) in September 2021. Prosecutors involved in the mishandled case testified on July 5th, 2023.

“If I could go back and make a decision, I would make the same one,” said the leading prosecutor on Aishima’s case.

On December 27th, an investigator from the Metropolitan Police Department testified that the case was fabricated. The court ruled the investigation illegal and ordered the government and Tokyo to pay the plaintiffs ¥160,000,000 (USD 1,097,544). On January 10th this year, the government and Tokyo appealed.

Plaintiffs, including Aishima’s son, expressed their utter disappointment in the unapologetic response.

“I want them to apologize, in front of his grave,” says Aishima’s wife.

She says that Aishima had bought supplies to build his dream hut next to Mt. Fuji before he died.

They’re still there.

What to read next


[1] がんでも閉じ込められ…無実だった技術者の死. NHK

[2] 「墓前で謝罪を」保釈されずに病死の夫 妻がみつめた無念 大川原化工機冤罪事件で判決. テレ朝news

[3] 不正輸出めぐるえん罪事件 国と都の控訴に原告側“あきれた”. NHK

[4] 父は被告のまま亡くなった…無念の息子の訴え 罪を認めるまで長期間拘束する「人質司法」これでいいのか. 東京新聞

[5] 不正輸出事件で突然の逮捕、長期勾留…起訴取り消しの社長「無実明らかに」 国に賠償求め提訴. 産経新聞

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