If you replace a city piece by piece — at what point does it stop being itself?

In a parallel world, Hong Kong looks very different. When the British counted their new island in 1841, they found 7,450 people in sixteen villages — about a quarter of them living on boats. What turned that coastline into this was a drug war, two treaties, and the strangest clause in urban history: a 99-year lease with an expiry date every resident could read.

Scroll through the timeline. The thing to watch isn't the dates — it's the idea that takes shape between them: a world city built, knowingly, on borrowed time. And in those 99 years, a lot of things happened.

"Tong lau" literally means Chinese building — the counterpart of the yeung lau the British built for themselves. Shops on the ground floor, families stacked above, maybe a factory in the back. When the refugees poured in and Hong Kong's population doubled and doubled again, this was the building that absorbed it all.

From about a thousand registered factories in 1947 to more than ten thousand two decades later — and a lot of them ran inside tong lau. Fabric wheeled in from the docks at dawn; shirts, wigs, plastic flowers stitched on the upper floors; boxes stamped "MADE IN HONG KONG" and shipped to Macy's and Marks & Spencer by nightfall. The whole life cycle of a product, compressed into one address. And under British law a Chinese family could own that address — pass it down, borrow against it — while ownership was being abolished across the border. So the money moved here.

Today the tong lau are coming down — old, out of code, worth less than the land under them. When one is "saved," what's saved is often just the façade: tenants out, boutique in where the sewing floor used to be. The exceptions are instructive. A 1926 corner tong lau in Sheung Wan — one of the last half-dozen of its kind — kept its hand-carved terrazzo signage and its social life: the ground floor is a free community living room now. It was only possible by removing the pressure for profit from the equation. Remember that sentence.

Start underground: the MTR's first line opened in 1979, and instead of building the city first and adding trains later, Hong Kong built the trains and let the city grow around them. The Rail-plus-Property model is a perpetual motion machine — the MTR develops the land above its own stations, property revenue funds the railway, the railway raises property values. In 2015 fares alone covered 187% of operating costs — the highest farebox recovery ever recorded; even in the worst pandemic year it stayed above break-even. New York's subway recovers less than a third.

Above every station, the same section repeats: station at the base, shopping podium on top, residential towers above that — the architects we met call them birthday cake developments. Stack hundreds of them side by side, string them together with escalators, footbridges and malls, and the whole city starts working in three dimensions. The fastest way around stops touching the street. Scroll to climb the section.

A street that weaves in and out of malls — somebody paid to build it. Most of Central's elevated network is privately owned, attached to malls and offices. There are lists of things you're not allowed to do, and at some point you're strongly encouraged to buy something. The ground was never just circulation; it's where public life happens — hanging out, meeting up, without buying anything. Hong Kong engineered a city that quietly priced that out.

Then, every Sunday, the arrangement inverts. Hong Kong's 368,000 foreign domestic workers are required by law to live in their employers' homes — so on their one day off there's nowhere private to go, and at a wage set apart from the minimum-wage ordinance, cafés aren't an option either. So the city's most invisible workforce claims its most corporate spaces: the footbridges, the plazas, and the open ground floor under Norman Foster's HSBC tower — the icon we all studied in architecture school, its floors hung from steel masts so the ground level could stay open as covered "public space."

Choi Hung — "rainbow" — is one of Hong Kong's oldest and most iconic public housing estates: eleven blocks, deliberately staggered heights, a shopping centre, schools, a wet market, and of course the basketball court. A tight-knit mini city where shopkeepers know every family by name, and people have lived in the same block for fifty years.

The case for demolition is the engine again: the buildings are old, the waitlist for public housing peaked at over six years, and the Housing Authority is measured on exactly that — units delivered. Rebuilding adds 1,800 flats on the same land, up to modern code, in three phases running from 2028 to around 2049 — a twenty-one-year unmaking. Even if a retrofit could work, rebuilding is what the system rewards. For the film we interviewed Don Hong — a KPF architect with the Save Choi Hung Estate research group — who is trying to make the alternative legible to the spreadsheet.

When you opened a shop, you commissioned a master sign maker — someone who bends the glass tube over a flame and blows into it so the walls don't collapse. Different gases, different colours; three to fifteen thousand volts, and it glows. The sign got passed down to your kids and your grandkids, because the sign becomes the shop. Scroll — each gas ignites.

One honest footnote: the gases are the alphabet, but the trade got most of its palette from phosphor-coated and tinted tubes over argon-mercury. The coatings are the vocabulary.

This is the atmosphere of Hong Kong — reds and greens dripping onto wet pavement, the lonely intimacy of Fallen Angels, the city Oshii fell in love with. And over the last decade, thousands of these signs have come down. The rules were always there — projecting signs have counted as unauthorized structures for decades. What changed is enforcement: removal orders nearly doubled between 2015 and 2022, sixty days to comply. The choice: take the sign down, or replace it with a smaller certified LED panel, flush against the wall — at least HK$15,000 in engineering and permits by the estimates we heard, and published cases run far higher. Some shops closed. Some can't afford it. And the ones that could… mostly don't. It pales in comparison to what was there before.

How many hands in this city can still bend a character in glass? Wu Chi-kai — forty years at the flame — counts maybe eight or nine masters left, average age past sixty. The basics take six months; mastery, years. One master, Wong Kin-wah, rebuilt his European burners to run ten times hotter — because Chinese characters bend in ways Roman letters never asked to.

Honestly — we came expecting a story about political pressure, an identity crisis, something being taken from the people. But after talking to people here, the biggest driver of all this change is simpler: efficiency and profit. The same engine that created Hong Kong — now running at a hundred times the speed, on the planet's most expensive housing market, where every square inch has to justify itself.

Memory, texture, identity — they don't add direct value on a spreadsheet, so they're hard to argue for. Especially the cheap neon and the concrete housing blocks: utilitarian, working-class, just background. But sometimes the background is the identity. Museums, photos, films — they let you see your history. Only architecture lets you live in it. That's a gift only architecture can give — and it's the first thing a system built to optimize will take away.

Every conversation about cyberpunk Hong Kong eventually reaches Kowloon Walled City — and the film deliberately doesn't. Its story is about the living city, not the famous dead one. But the research kept leading back here, so the booklet keeps it: the enclave excluded from the 1898 lease, ungoverned in practice by either empire, where some three hundred interlocked towers rose without an architect to a density of roughly 1.25 million people per square kilometre — the highest ever recorded — before demolition in 1993–94.

We filmed the bronze scale model in the park at night, and the exhibition recreations nearby — a city mourning a city, in miniature. If the film's question is what a city loses when it optimizes, the Walled City is the inverse case study: the one place the engine never reached, remembered now mostly through photographs — and through the genre it accidentally created.