You’ve seen the neon. If you’ve spent more than twenty minutes wandering through the frantic, humid streets of Causeway Bay, specifically near the intersection of Hennessy Road and Canal Road, you have definitely seen it. It’s a slim, unassuming vertical slab of concrete. It doesn't look like much from the outside. But the Fuji Building in Hong Kong is arguably one of the most talked-about, misunderstood, and "infamous" addresses in the entire city.
People call it a "vertical red-light district." Others see it as a gritty relic of an older, weirder Hong Kong that is slowly being polished away by luxury malls and sterile glass towers. Honestly, it’s a bit of both.
Walking past the entrance, you might just see a security guard or a few people looking slightly shifty as they check their phones. There is no grand lobby. There is no signage that screams what is happening upstairs. Yet, it is a landmark in its own right, functioning as a decentralized hub for the city’s independent sex work industry. It’s a place that exists in a very specific legal gray area that most locals understand but rarely discuss in polite company.
The weird legality of the Fuji Building in Hong Kong
How does a place like this even exist in a city known for its strict, buttoned-up financial image? It’s all about the "one-woman brothel" rule.
In Hong Kong, under the Crimes Ordinance, it is not actually illegal for a single person to sell sexual services from a private residence. What is illegal is "keeping a vice establishment," which usually involves more than two people working together, or someone else profiting from the labor (pimping). Because the Fuji Building is essentially a collection of small, subdivided units where each individual works independently, it effectively bypasses many of the laws that would shut down a traditional brothel.
It’s basically a loophole turned into a skyscraper.
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Each floor is a maze of doors. Most are painted in bright colors or adorned with specific lights—often pink or purple—to signal they are open for business. You won’t find a central manager. You won’t find a "madam." It’s a marketplace. This decentralized nature is exactly why the Fuji Building in Hong Kong has survived for decades while other more traditional "nightclubs" in Wanchai have been raided or priced out by rising rents.
What it’s actually like inside
Don't expect the Ritz.
The elevators are small and usually crowded. They move slow. You’ll see a mix of people: curious tourists who read about the place on a forum, local office workers in cheap suits, and delivery drivers carrying lukewarm takeout. It’s cramped. The air usually smells like a mix of industrial floor cleaner, cigarette smoke, and the heavy, humid scent of the city outside.
Each unit is tiny. We are talking Hong Kong "micro-flat" tiny. Maybe 100 to 150 square feet if they're lucky. In that space, there is usually a bed, a small bathroom, and maybe a chair. It’s functional. It’s transactional.
One thing that surprises people is the diversity. While many workers are local or from mainland China, the Fuji Building is known for being international. You’ll see doors indicating workers from Thailand, Russia, Japan, or South America. This international flavor is part of why it’s gained such a reputation on travel forums and "underground" city guides. It’s a microcosm of the city’s migrant labor patterns, just focused on a very specific industry.
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The economics of the "Vertical Brothel"
Rents here are astronomical compared to the size of the units. Landlords who own these subdivided spaces know exactly what they are being used for. They charge a premium because they are essentially selling a "safe" space where the police are less likely to kick down the door due to the legal loopholes mentioned earlier.
A single room might rent for twice or three times the market rate for a similar-sized residential unit in the same neighborhood. It's a brutal business model. The workers have to cover these overheads before they make a cent of profit. This pressure means the building is active 24/7. It never sleeps.
Why the building persists despite gentrification
Causeway Bay is some of the most expensive real estate on the planet. Directly across the street, you’ll find high-end boutiques and Michelin-starred restaurants. So why hasn't a developer bought the Fuji Building and turned it into a boutique hotel or a "co-living" space for tech bros?
- Fragmented Ownership: Like many older "Tong Lau" (tenement) buildings in Hong Kong, the ownership is a mess. Dozens of different individuals own different units. Getting them all to agree to sell to a developer is a nightmare that can take years of legal maneuvering.
- The Yield: As long as the current "tenants" are paying those inflated rents, the owners have very little incentive to sell. The building is a cash cow.
- The "Shadow" Economy: Hong Kong has always had a degree of tolerance for these types of zones, provided they don't cause "public disorder." The Fuji Building is relatively self-contained. It doesn't spill out into the street with aggressive touts like some parts of Tsim Sha Tsui.
Safety and the "Grey" Reality
Is it safe? That’s a complicated question. For the clients, it’s generally considered safer than street-level solicitation because there are cameras in the hallways and other people around. For the workers, it’s a different story. While the "one-woman" rule provides legal cover, it also means these individuals are working alone behind a locked door.
There have been incidents over the years. In 2023 and 2024, there were several reports of "smash and grab" robberies within the building. Because the work exists in a legal grey zone, workers are sometimes hesitant to report crimes to the police, fearing that their immigration status or "business" might be scrutinized.
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Organizations like Zi Teng, a Hong Kong-based NGO that advocates for the rights of sex workers, frequently visit the Fuji Building. They provide health supplies, legal advice, and a bridge to social services. They argue that the building, while far from perfect, is a necessary evil that provides a level of security and community that wouldn't exist if the trade were pushed further underground or into the shadows of industrial parks.
The Future of the Fuji Building in Hong Kong
The clock is ticking.
Hong Kong is changing fast. The "Old Hong Kong" of the 1990s—gritty, neon-soaked, and chaotic—is being replaced by a more regulated, sanitized version of itself. The Fuji Building feels like a glitch in the matrix. It’s an anomaly.
Eventually, a developer will successfully consolidate the titles. Or the government will tighten the "one-woman" loophole under the guise of "public morals" or "urban renewal." When that happens, the Fuji Building will likely be torn down and replaced by a skinny glass tower with a name like The Zenith or Harbour View Suites.
But for now, it remains a strange, vertical village. It’s a place that tells a story about Hong Kong’s housing crisis, its legal quirks, and the invisible lives of the thousands of people who keep the city running in ways the official tourism boards would rather you didn't see.
Practical Insights for the Urban Explorer
If you find yourself in Causeway Bay and want to understand this side of the city's history, keep these things in mind:
- Respect the Privacy: This isn't a tourist attraction. It is a place of work for people in precarious positions. Taking photos inside the hallways or of individuals is not just rude—it can be dangerous and will likely lead to a confrontation with building security.
- Observe the Architecture: From the outside, look at how the building has been modified. The window units and the haphazard wiring are classic examples of how Hong Kongers maximize every square inch of space.
- Understand the Context: Don't view the Fuji Building in isolation. It exists because of the city's extreme wealth inequality and its unique colonial-era legal system. It is a symptom of a larger economic reality.
- Support Local Advocacy: If you are interested in the human rights aspect of these "vertical brothels," look into the work of groups like Zi Teng. They offer the most accurate, boots-on-the-ground perspective on the challenges faced by those living and working in the building.
The Fuji Building isn't "hidden." It’s right there in plain sight. It’s just that most people choose to look the other way. Understanding why it exists gives you a much deeper, more honest look at the real Hong Kong than any luxury mall ever could.