University of Tokyo prof held over ‘soapland,’ club bribery case

Asahi
January 26, 2026

The University of Tokyo’s Akamon gate in Tokyo’s Bunkyo Ward (Asahi photo

A University of Tokyo professor was arrested on suspicion of accepting about 1.8 million yen ($11,700) in bribes, including entertainment at high-end clubs and sex-industry “soaplands,” in exchange for research favors.

Investigative sources said Shinichi Sato, a 62-year-old professor at the University of Tokyo Graduate School of Medicine, likely received much more for his cooperation in a joint study on whether cannabidiol (CBD), a substance found in cannabis, can be used to treat skin diseases.

The Metropolitan Police Department on Jan. 26 said it has submitted papers to prosecutors about the suspected briber, Koichi Hikichi, 52, head of the private-sector Japan Cosmetic Association.

Sato’s former subordinate, Ayumi Yoshizaki, 46, has also been implicated.

Sato’s arrest concerns about 1.8 million yen in entertainment that Sato, a resident of Tokyo’s Bunkyo Ward, allegedly received from Hikichi, a resident of Kishiwada, Osaka Prefecture, between March 2023 and August 2024.

Yoshizaki, who also lives in Bunkyo Ward, gained 1.9 million yen around the same time, they said.

Hikichi is suspected of providing a total of 3.8 million yen in bribes, which included around 30 visits to high-end clubs and soaplands.

As employees of a national university, Sato and Yoshizaki are considered “public servants” subject to anti-bribery laws.

The Bunkyo Ward-based Japan Cosmetic Association was established in 2012 with the stated purpose of “conducting business related to cosmetics and contributing to the widespread popularization of cosmetics.”

Hikichi had grown particularly interested in the growing use of CBD in treating skin diseases.

“I want to conduct clinical research at the University of Tokyo’s medical school, the most famous in Japan, to demonstrate the effectiveness of CBD and connect it to commercialization,” Hikichi reportedly told people around him.

Around May 2022, after Hikichi had an online meeting with Sato through a third party, proceedings for a collaboration moved forward.

In March 2023, Hikichi’s association concluded a contract with the university to establish a course for conducting joint research on CBD.

Sato, a well-regarded dermatology expert and a 2021 recipient of the University of Tokyo Hospital director’s award, was given authority over the joint research project.

The association agreed to provide 30 million yen annually for the “clinical cannabinoid studies” course, which Sato oversaw.

According to police, the entertainment was a reward for Sato’s help in establishing the course.

Hikichi reportedly told the two academics he intended to share future profits from CBD-related businesses with them. He requested additional research, including studies on the selective breeding of cannabis plants.

The research project, planned for three years, initially proceeded smoothly.

According to Hikichi, the relationship deteriorated in August 2024 after Sato and others demanded money from him.

In September 2024, Hikichi consulted with Tokyo police, saying the monetary demands from Sato and others were a case of attempted extortion.

In March 2025, the University of Tokyo terminated the contract for the joint research and the course.

Two months later, Hikichi filed a lawsuit against Sato and the university, seeking 42 million yen in damages. The ongoing lawsuit claims the academics forced him to provide lavish entertainment and then unilaterally terminated the research.

Sato has countered that Hikichi “completely failed to abide by many of the matters he had promised.”

LAVISH DINNERS

Court records and interviews with investigators showed that the first time Hikichi entertained Sato was on Feb. 14, 2023, at a high-end French restaurant in Tokyo’s Yurakucho district.

The bill for the meal for three, including Sato and Hikichi, was 156,358 yen.

According to investigators, Hikichi paid the full amount, saying, “I thought that a professor at the University of Tokyo would dine at such high-end restaurants.”

Sato himself had arranged this dinner outing, investigators said.

After that, Hikichi began entertaining Sato and others at lavish restaurants about twice a month.

Court records showed that the outings included 136,140 yen for a “suppon” soft-shelled turtle and “fukahire” shark fin dish in Tokyo’s Ginza district, 101,310 yen for Italian food in Tokyo’s Nishi-Azabu district, and 97,900 yen for sushi in the Ueno district.

Eventually, the entertainment continued after dinner. Hikichi began to entertain them at expensive clubs in Ginza, spending several hundred thousand yen, according to the sources.

From April 2024, Hikichi claimed, they began going to soaplands in Tokyo’s Yoshiwara district that cost over 200,000 yen per visit.

In the lawsuit, Sato said he intended to pay for the meal at the Yurakucho restaurant, but “was unable to because (Hikichi) paid while he was in the restroom.”

Sato admitted to having gone to soaplands but insisted that Hikichi “was the one who proactively invited” them.

UNIVERSITY VOWS REFORM

After the scandal came to light, the university in June 2025 established a committee for verification and reform of social cooperation programs.

In October, it announced reforms on research and education projects conducted with funds from private companies.

“We will immediately implement these reforms and build an appropriate operational structure with enhanced governance,” President Teruo Fujii said.

However, the university faced renewed scrutiny after the arrest of a doctor from the University of Tokyo Hospital on suspicion of bribery in November.

At the end of last year, the university was not selected as an “international university for research excellence” due to its poor handling of successive scandals. The status allows such schools to receive government support funds.

Fujii released a statement on the university’s website on Jan. 25, saying Sato’s arrest is “extremely regrettable, outrageous, and deplorable. We take this matter extremely seriously and will deal with it strictly.”

He said that through the university’s own investigation, “specific issues became clear regarding faculty and staff compliance awareness, the system for checking the acceptance and use of private funds, and the organizational culture for preventing and detecting such situations early on.”

It is not clear if the entertainment expenses had an effect on the joint research results or other aspects of the study.

However, a senior MPD investigator warned: “A serious collusive relationship has formed behind this industry-academia collaboration, which could undermine trust in the system itself. This could cast doubt not only on the legitimacy of the research but also on its safety.”

According to the university's website and other sources, Sato graduated from its Faculty of Medicine in 1989 and then studied at Duke University in the United States. He became a professor at Nagasaki University’s Graduate School in 2004, and then a professor at the University of Tokyo’s Graduate School in 2009.