<figure id="attachment_438011" class="wp-caption alignnone" style="width: 1920px;" aria-describedby="caption-attachment-438011"><a href="#" data-ident_hash="58255cd9"><img src="https://res.cloudinary.com/fridaydigital/image/private/t_article_image/wpmedia/2025/09/aeaa5d00541d557ddeb1d420712ff902.jpg" alt=""></a><figcaption id="caption-attachment-438011" class="wp-caption-text">The &#8220;Green Sauna&#8221; that was exposed. What kind of service was being offered here?</figcaption></figure>
<p data-start="0" data-end="582">Once famed nationwide as the home of the “NK style,” Nishikawaguchi has seen most of its former sex-related businesses vanish. By September 4, the Saitama Prefectural Police had arrested the owner, Minja Kwak (61), along with two other women of Korean nationality and two female employees of Chinese nationality, on suspicion of violating the Entertainment Business Act (operating in a prohibited area). Between August 10 and September 3, they allegedly ran a sex-related business in a banned zone, providing sexual massages to unspecified male customers or assisting in doing so.</p>
<p data-start="584" data-end="1098"><strong>&#8220;The raided ‘Nishikawaguchi Green Sauna’ was registered as a public bath in 2019, featuring both a sauna and bathing facilities. However, for certain courses, customers could receive sexual services in addition to scrubs and massages for around 10,000 yen. The shop reportedly employed five to six workers. Police estimate that at least 10,000 customers visited in the past year, generating over 100 million yen in revenue, and are investigating accordingly,&#8221; </strong>said a national newspaper social affairs reporter.</p>
<p data-start="1100" data-end="1293" data-is-last-node="" data-is-only-node="">&#8220;FRIDAY Digital&#8221; had previously reported an undercover investigation of the same shop in March by YouTuber and underground explorer Pineapple Ura Channel. The article is being republished here.</p>
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<h3><span class="strongInContent"> Underground sauna still in business in a town where the NK school has died out</span></h3>
<p data-start="0" data-end="282">Kawaguchi. Recently, the city has been in the news for friction between the Kurdish community and local residents, making it a topic of discussion. Just outside the west exit of Nishi-Kawaguchi Station lies the red-light district, lined with soaplands and storefront health clubs.</p>
<p data-start="284" data-end="663">Nishi-Kawaguchi Station opened in 1954, two years after the Kawaguchi Auto Race track was established in 1952, and the sex industry developed alongside it. The Urawa Racecourse and BOAT RACE Toda (Toda Boat Race Course) are also nearby. Whether men win or lose at gambling, many are drawn to the red-light district. Nishi-Kawaguchi has continuously met that demand to this day.</p>
<p data-start="665" data-end="1050">And when it comes to Nishi-Kawaguchi, there’s the so-called “NK style.” Short for “Nishi-Kawaguchi style,” it refers to bona fide sexual salons. The exterior and interior of the shops resemble a pink salon, but at the peak of its popularity, over 200 establishments offered sexual intercourse with Japanese women in their twenties for around 10,000 yen. This was until the mid-2000s.</p>
<p data-start="1052" data-end="1346" data-is-last-node="" data-is-only-node="">Though the once-thriving NK style had collapsed even before the Reiwa era, Nishi-Kawaguchi still hosts a peculiar type of establishment. To put it bluntly, it’s a sauna—but since we’re writing about it, it’s obviously no ordinary sauna. It’s a “gentlemen-only,” “adults-only” underground sauna.</p>
<div data-friday-nextpage-lead="What are its services? ......"></div>
<h3><span class="strongInContent">Why &#8220;underground saunas&#8221; have survived in Nishi-Kawaguchi</span></h3>
<p data-start="0" data-end="230">In short, it’s a “sauna that offers sexual services.” This isn’t an urban legend, nor has its existence been completely unknown. Anyone with even a passing interest in underground adult entertainment would likely be aware of it.</p>
<p data-start="232" data-end="556">There are two such underground saunas around Nishi-Kawaguchi Station: [○○○○ Sauna] and [○ Sauna]. I visited both, and their services are surprisingly similar, with prices nearly identical. They’re so alike that I initially thought they might be part of the same chain. Both are reputed to offer highly unusual experiences.</p>
<p data-start="558" data-end="795">At [○○○○ Sauna], for example, a 60-minute course including body scrubbing (akasuri) and massage costs 9,000 yen. After a thorough scrub, customers receive a full massage to relax their body, during which the sexual service is provided.</p>
<p data-start="797" data-end="1185">Why do these unconventional saunas exist in Nishi-Kawaguchi? One likely reason is the absence of public baths near the station. After using NK-style salons, men probably wanted to wash themselves. The key point is that NK-style salons were “honban” (full-service) establishments. Most of them likely didn’t have showers—the main difference between health salons and full-service salons.</p>
<p data-start="1187" data-end="1561">Men probably wanted to wash off sweat after sexual encounters before heading home. The creators of these saunas likely realized that by adding akasuri and sexual services to a bathhouse, they could better meet the demand of visiting men. Notably, [○○○○ Sauna] has existed since the early 2000s, even though NK-style salons were completely shut down by authorities by 2006.</p>
<p data-start="1563" data-end="1701" data-is-last-node="" data-is-only-node="">While NK-style salons have vanished, these underground saunas have continued operating, remaining a symbol of Nishi-Kawaguchi to this day.</p>
<p>In the paid version of &#8220;FRIDAY Subs,&#8221; Pinappo Urach&#8217;s report on the actual infiltration of underground saunas is introduced, along with photos.</p>
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<div data-friday-gold-link-url="https://friday.gold/article/325032" data-friday-gold-link-title="Underground exploration: Remnants of the NK style?　...A &quot;sauna with nuki&quot; that has been quietly operating across Nishi-Kawaguchi station for a long time." data-friday-gold-link-excerpt="Nishi-Kawaguchi Nishi-Kawaguchi was once known throughout Japan for its &quot;NK style. Kawaguchi is a town that has recently been in the news for its Kurdish problem. Just outside the west exit of Nishi-Kawaguchi Station, there is an entertainment district lined with soaplands and storefront health clubs. 1952" data-friday-gold-link-thumbnail-wide="https://assets.friday.gold/friday-wp-production-assets/app/uploads/2025/03/videoframe_1312651-10154430657393.jpg/v/crop-faces:width=256,height=144/format:type=webp?Expires=4102444800&amp;Key-Pair-Id=K2H5GZZHVJCN4V&amp;Signature=XFpHsj1zlVKA3bnLIsC~0pbQHdeTmop3F58fIGJrYQaT~-2hHEe7IxQrNFJi48gNILQNyVIjEghV1UNBwkMOEDu7p0LExOcyOk7uzTfxsYityKEq4w-d6v6pn1fS1afcoJuaVbVCyIW2wHYrMLjiu2db-Djbw1AxR6IEgL9Sf02njz7r8~sZxxJntiAvS72i4ScvLKp8x~fdrn21Nivo7buM1SNOJHNcgkLJA7D~tDLOVjBny1Y5Ln61vvnsP5dwzBChy6N9-XDExPseRUGWdzYUF02MPJPsBiCYZ9vfL3NtCkj9CQjB7l3uRFjM-Tdhcp7gNM~0SCixWe8V117yxQ__" data-friday-gold-link-thumbnail-square="https://assets.friday.gold/friday-wp-production-assets/app/uploads/2025/03/videoframe_1312651-10154430657393.jpg/v/crop-faces:width=105,height=105/format:type=webp?Expires=4102444800&amp;Key-Pair-Id=K2H5GZZHVJCN4V&amp;Signature=eCxtJry10CHnv7SMSh-elT8jCd9~JonHLIfcxf4J8R2xauWPtGfO03-5GCz8kQ-2b0nJZOyMz5MrxbGNcKsQUOSIPeE2kXAmV8IHgykMqXyQjPYlNP6GKYfOwP3ps1H4aFbwPDlB6ecnr~0whZjxlwaHmqeX5OBm0K1o62Vzy1iZeZpGVqfoqHhzqhAxlJoV383Kjzi5UvFQrEQqzmyv1A6BGQRylR9CpVDRmglB7BSS~ArX204ooRTEJLGd92kk1a6~hIJeZ93pzOxRslWawhQZ1tEdnQ~N~0dWWS36rfnLr867MIIZ9B4ztqPIVFYfqlQj-ZuVilszBab5Z46RYg__"></div>
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 Pinappo Urachu

 Saitama Prefectural Police have arrested four women, including the manager, for violating the Entertainment Establishments Control Law by providing sexual services to customers at a sauna in Kawaguchi City. In March, this magazine reported on the contents of the services provided at this sauna, which has been in operation in Nishi-Kawaguchi for more than 20 years.

Four Women Arrested for ‘Sexual Services’ at an Adults-Only Sauna in Nishikawaguchi

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