Press "Enter" to skip to content

Debts and deception: Manslaughter case for ‘monster in human skin’ underway

Miyuki Yamamoto, left, and Masaki Tanaka (Twitter)

FUKUOKA (TR) – Early on October 20, 2019, police responding to a distress call arrived at a parking lot for an internet cafe in Dazaifu City.

Officers found Rumi Kohata, 36, collapsed inside a vehicle. The woman, whose body had bruises throughout, including to her legs and abdomen, was confirmed dead at a hospital about 90 minutes later.

The results of an autopsy revealed that she died as a result of external trauma, Fukuoka Prefectural Police later said.

The person who placed the call was Tsubasa Kishi, a 25-year-old acquaintance of Kohata. Two days later, police arrested him and Miyuki Yamamoto, 41, on suspicion of abandoning the corpse of Kohata.

Along with a third defendant, Masaki Tanaka, a 47-year-old former member of a criminal syndicate, Kishi and Yamamoto are now facing trial.

However, the tale to this point is long and twisted, rooted in large debts, copious drinking and persistent deception — all at the hands of Yamamoto.

Rumi Kohata (Twitter)

“I was told to drink, but I didn’t have the money”

Fuji News Network (Oct. 1) conducted a number of interviews with persons involved in the case. Through the discussions, it became clear that Yamamoto was the ringleader, a person who could seemingly control the minds of the other players.

According to Kishi, Yamamoto has been involved in illicit debt collection since she was in her 20s. Her target area is the host clubs in the Nakasu red-light district of Fukuoka City’s Hakata Ward.

One bar host told the network that Yamamoto regularly ran up bills of around 100,000 during single drinking sessions. “She lives a flashy life of drinking with money seemingly squeezed from many debtors,” the host says.

Yamamoto’s strategy was to lure persons out for drinking and later present them with fictitious bills. One target was apparently Rumi Kohata’s older brother, Ryota. “I was told to drink, but I didn’t have the money, so I wondered if it was still fine,” he remembers. “I was told [by Yamamoto], ‘It’s fine, fine.'”

Only it wasn’t.

“I was later falsely labeled as one ‘who hasn’t paid his bill,'” he says of the incident, which took place about 10 years ago.

Miyuki Yamamoto, left, and Tsubasa Kishi (Twitter)

Manipulate the koseki

Tanaka, the former gangster, then entered the picture as a means of intimidation to collect that bill. Utilizing Tanaka was standard procedure for Yamamoto. However, if he couldn’t get the victims to pay, the next step was to manipulate the koseki, or the family register.

Kishi assisted Yamamoto in this regard. For his koseki, he is shown to have adopted Ryota. “I had to collect money, and to do that I had to connect with him through my family register. The method is according to Yamamoto-san’s instructions, but I can’t get into details for legal reasons,” Kishi says.

An examination of the register also shows that Kishi was married to a woman named Minako Sakai for a period of only two weeks. According to persons familiar with the matter, she died two years ago due to an illness.

“Minako died in the back seat of my car due to acute heart failure,” Kishi says. “But I still don’t think she died due to illness.”

Miyuki Yamamoto (Twitter)

“Monster covered in human skin”

Prior to her death, Sakai was forced to live with Yamamoto and Kishi. That was also the case for Kohata. When her brother disappeared, Kohata was tasked with taking over his debt, which also meant living with the defendants in an apartment in Fukuoka Prefecture.

The defendants then threatened and beat Kohata over the repayment of the amount, later revealed to be 3.05 million yen.

In causing her death, police allege that Yamamoto and Kishi repeatedly beat Kohata in the buttocks with a wooden sword and stabbed her with a butterfly knife in the leg on multiple occasions in September and October of last year.

Running afoul of the law is not unusual for Yamamoto. An investigator tells the web site for weekly tabloid Shukan Bunshun that she was arrested twice in 2016 for assaulting a 36-year-old man during the extortion of 355,000 yen. Over a three-year period ending last year, she defrauded a 28-year-old woman out of 10.26 million yen.

“I’ve seen the actions of Yamamoto-san up close for four years,” says Kishi. “So I think I know better than anyone else that Miyuki Yamamoto is a monster covered in human skin.”

Yamamoto said through her lawyer that she would not comment to the network.

Masaki Tanaka (Twitter)

Tosa Police Station

At the time, Kohata technically lived with her husband and their two children in the town of Kiyama, Saga Prefecture.

The defendants also targeted Kohata’s other family members. Prior to the death of Kohata, her husband, Hiroshi, and other relatives claim to have consulted with police in Saga Prefecture on roughly one dozen occasions about the actions of Tanaka, who allegedly tried to extort the 3 million yen from him in August and September of 2019.

On October 31, the Tosa Police Station acknowledged that officers were
contacted eight times by the family about Kohata being in danger. However, the officers did not pursue an investigation. “It was appropriate,” a representative of the station said.

In proving their claims, Hiroshi provided police with a recording of a phone call made by Tanaka. He said he was a gang member in demanding payment. However, investigators refused to take on the case.

“Saga prefectural police did not take our complaints seriously,” Kohata’s mother told the Asahi Shimbun. “If they had listened to what we said, the incident would not have occurred.”

Miyuki Yamamoto in her 20s (Twitter)


Yamamoto and Kishi have been indicted for manslaughter and abandoning a corpse. She also faces charges of attempted extortion. Her trial for the latter harge began began at the Fukuoka District Court on November 10.

“I didn’t attempt to extort, nor did I conspire to,” she told the court in denying the allegations.

“It’s scary to cut off ties with yakuza,” said Hiroshi Kohata at the trial. “I thought I would get abducted and roughed up. I thought that just dying would have been easier.”

For Tanaka, prosecutors are seeking a prison term of 30 months for the abandonment charge and attempted extortion.

During his trial, prosecutors said that the defendants used a vehicle to move Kohata’s body from Hakata Ward in Fukuoka City to the parking lot in Dazaifu. They further alleged that he made the decision about whether to leave her body and how to cover up the crime.

The defense countered by saying that the act of moving a body does not constitute abandonment.

Regarding the attempted extortion, Tanaka admitted to the allegations. The defense is requesting a suspended sentence for that charge.

The ruling in Tanaka’s case is expected to be handed down on January 21, 2022. Yamamoto’s next hearing is scheduled for November 25. Kishi’s trial has not started yet.