A deadly fire killed a married couple inside a private sauna in Tokyo’s Akasaka district on December 15. The incident has lit up Japanese social media, raising serious questions about how this facility and related businesses ensure customer safety.
Safety failures raise serious questions
Akasaka, Tokyo. (Picture: 天空のジュピター / PIXTA(ピクスタ))
The incident occurred at a high-end, members-only facility known as Sauna Tiger. The victims were Matsuda Masaya, 36, and his wife, Matsuda Yoko, 37. Police found the couple collapsed inside a small, glass-enclosed sauna room. They lay near the entrance, with Masaya covering Yoko as if to protect her.
Investigators observed bruising beneath the skin on Masaya’s fists. The marks suggested he repeatedly struck the inside of the door. The sauna door did not open, trapping the couple inside.
Former police detective Akiyama Hiroyasu said the door was closed and could not be opened from within. He said a broken doorknob likely caused the entrapment.
Both the inner and outer doorknobs had detached and fallen to the floor. Police believe the couple became unable to escape as conditions worsened. Burn marks appeared on the sauna bench, backrest, and a towel.
Investigators believe the fire began when a towel touched heated sauna stones. Masaya suffered burns across his upper back, while Yoko suffered burns on her right shoulder and arm. Authorities continue to investigate the exact cause of death.
Emergency button system had no power
Investigators found signs that the couple pressed the emergency button inside the sauna. However, the system failed to function. Police later discovered that the emergency receiver panel had no power.
Later, the sauna’s owner told investigators he had never turned the receiver on and had never handled it. As a result, the emergency alert never reached staff.
Employees became aware of the fire only after a smoke sensor outside the sauna activated. By the time staff responded, the couple had already died. Former customers said it would have been impossible to call for help from inside the sauna. The room was located within another sealed room, blocking sound.
Sauna professionals expressed shock and anger at the safety failures. Many said emergency alarms must always remain operational. Kurachi Satoru, manager of Spa Alps in Toyama City, called the situation unacceptable. He has worked in ten sauna facilities for over 25 years. Kurachi said he has never seen a sauna room that used a standard doorknob.
He explained that saunas create extreme heat and humidity. Wet, sweaty hands place heavy stress on door hardware. In private rooms, staff cannot monitor misuse or wear. Kurachi said the sauna doors must open by simply pushing. Customers want to exit immediately during emergencies, making complex door mechanisms dangerous.
Medical experts describe extreme heat dangers
Picture: maroke / PIXTA(ピクスタ)
Medical experts believe the couple remained trapped in extreme heat for a prolonged period. A specialist reviewing the scene suggested that long exposure caused their deaths. Dr. Ozaki Akihiko of Joban Hospital explained that a 90-degree sauna becomes dangerous after about 20 minutes. He said the body enters a state known as heat illness.
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During extreme heat, the body loses water rapidly through sweat. Eventually, sweating can no longer regulate body temperature. Internal heat continues to rise while dehydration worsens. Blood pressure drops, increasing the risk of collapse. Victims may lose consciousness or experience seizures. Heart abnormalities and organ failure may follow.
Dr. Ozaki said these conditions can quickly become fatal. The longer someone remains trapped, the greater the danger. Former detective Akiyama described the scene emotionally. He said the husband likely tried to shield his wife until the end. He said the couple must have suffered greatly.
Police have not yet finalized the official cause of death. Authorities conducted judicial autopsies and continue to investigate both criminal and structural responsibility. Investigators are examining every room in the building. They are focusing on door design, alarm systems, and maintenance records. Officials say the investigation may take a long time.
Sauna industry reaction and online backlash
Sauna Tiger opened in August 2022 and quickly gained attention. The facility promoted luxury and privacy, including celebrity involvement at launch. It offered fully private rooms with saunas, water baths, and resting areas. Prices ranged from 19,000 yen ($127) per visit to monthly memberships costing 390,000 yen ($2,600).
Private saunas expanded rapidly during the COVID-19 pandemic. They offered non-contact, high-end experiences. Sauna Tiger followed this trend.
After the deaths, criticism spread quickly online. Sauna enthusiasts posted lists of facilities using similar doorknobs. Some labeled those facilities dangerous.
However, some commentators, such as Tanabe Kenji, former deputy editor of Weekly SPA!, warned against oversimplifying the blame. He said that focusing on a single design feature misses broader safety issues and that staffing facilities with monitoring can prevent emergencies. Further, he warned that careless accusations could cause reputational harm.
Sauna worker and performer Amaki Jun expressed deep shock and sadness. She said she imagined the couple’s final moments. Amaki has visited around 200 sauna facilities. She said customers rarely inspect doors or handles. She urged guests to report smoke, strange smells, or unusual conditions immediately.
Operator’s background draws scrutiny after deaths
SAUNA&Co, the company that runs Sauna Tiger in Akasaka.
As the investigation continues, attention has turned to the sauna’s operator. Sauna Tiger is run by SAUNA&Co, a Tokyo-based company founded in July 2021 by a businessman identified as A. He is in his late forties and known to be a longtime sauna enthusiast, according to acquaintances.
SAUNA&Co is effectively part of a larger corporate group. A also founded a visiting purchase company called KUROFUNE&Co, based in Chiba. Leadership of SAUNA&Co formally transferred last December to a close associate, identified as B. However, sources say the business remains under A’s influence.
In November, KUROFUNE&Co received a nine-month business suspension from the Consumer Affairs Agency. Authorities cited violations of the Specified Commercial Transactions Act. According to official documents, the company allegedly used misleading tactics to secure home-visit appointments. Once inside, staff reportedly pressured customers into selling valuables.
An employee later came forward as a whistleblower. The employee said staff were instructed to make false appointment claims. He said they dismissed items customers wished to sell and then pushed them to sell jewelry and watches, which he described as forced buying. He added that the management directed the conduct.
The whistleblower stated that unethical practices were prevalent throughout the group. He said poor corporate ethics may have contributed to the sauna tragedy.
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Bunshun sought comment from A and the company. They received no response at the time of publication.
Government’s response
Following the incident, the Osaka Prefectural Government issued a public safety warning. The announcement addressed private sauna operations nationwide. Officials referenced the Tokyo deaths and cited reports of broken doorknobs and non-functioning emergency buzzers. They stressed that investigations remain ongoing.
The government issued specific guidance for sauna operators. Officials urged regular checks of door operation and hardware integrity. They called for routine inspections of emergency buzzers and receiver panels. Operators must ensure power remains on at all times.
Authorities also instructed facilities to post clear safety signage. Emergency button locations and evacuation routes must be visible. Officials emphasized the need for staff readiness during emergencies.
The announcement also addressed sauna users. Officials acknowledged the health and relaxation benefits of sauna bathing. However, they warned that high heat and humidity increase accident risks. They urged users to check door and emergency button locations before entering, avoid overexertion, and listen to their bodies. Anyone feeling unwell should notify staff immediately.
Sources
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