Picture one continuous block, 14 storeys high, on 2.6 hectares of Kowloon City: about 350 buildings fused so tightly you could cross from north to south without touching the ground. Children did their homework on the roofs, among the antennas and water tanks. Below, alleys often only 1 to 2 m wide ran between typical 23 m² flats; a few were lit by fluorescent tubes, because sunlight rarely reached the lower levels. A 1987 government survey counted about 33,000 residents. No architect drew it, no planner zoned it, and no building code reached it.

This is the real prototype of the cyberpunk city, built by its residents and local developers. Architect Ian Lambot, who photographed it 30 or 40 times, writes in Architectural Design (vol. 87, 2017) that it “grew without input from architects or planners” and “has much to teach us about bottom-up, community-driven development”.

Three constraints, one author

The 1898 Convention leasing the New Territories to Britain excluded the walled enclave, and after 1945 governance stayed minimal. With no code in force, three constraints drew the building:

• A fixed footprint, roughly 210 m by 120 m. Nothing could spread, so everything stacked.
• The Kai Tak flight path. The airport had already taken the wall, demolished during the Japanese occupation (1941–45) to extend it. Later, its approach capped the roofline at 13 to 14 storeys; the towers rose to it and stopped.
• A few pipes. Eight municipal pipes served the whole structure; water and propane went upstairs by hand.

According to Greg Girard and Ian Lambot’s City of Darkness Revisited (2014), the early two- and three-storey squats jumped to six and seven storeys in the 1960s, a threshold that demanded reinforced concrete. “Alleyways and passages evolved – unplanned – into the established ‘map’ of the City,” the book records. The flight path drew the skyline. PAZ’s reading: constraint is always a co-author, and here it was the only one.

The 14K and Sun Yee On triads ran brothels, gambling and opium dens; in 1973–74 police made more than 3,500 raids and seized more than 1,800 kg of drugs. Foundations were poor and drainage was scarce. Yet the same fabric held factories, shops, schools and unlicensed dentists, “all other normal urban provisions” in Lambot’s phrase. The trade-off is plain: a city drawn only by constraint buys its density with daylight, sanitation and safety.

←TODAY: A film-set copy of the Walled City stands on its site until 2028.
→3012: Zurich-3012 zones in rule sets, and the skyline is whatever the rules leave open.
Fulcrum: Where constraint is the only author, the roofline is the rulebook.

The envelope before the first line

Every Swiss office works with the same author. The Bau- und Zonenordnung sets the height, the Grenzabstand keeps the walls back from the boundary, and near Zurich Airport the Sicherheitszonenplan adds its own ceiling. The Walled City is that envelope, filled only by its residents’ decisions. The question it hands back: which lines in your current section did the code draw, and which did you?

The genre kept the silhouette: Gotham’s Narrows in Batman Begins, the game Stray and William Gibson’s Bridge trilogy all drew on the Walled City. What the market sells is the density without the people, or the homework on the roof.

Atelier: Offices handing massing studies to generative tools run a small Kowloon of their own: the rules fence the field, the algorithm fills the rest, and the team moves from author to curator. Monday move: set the rule that no massing run starts until the legal envelope sits in the Archicad model as a locked reference solid, each face labelled with the rule that drew it.

Hack: Draw the envelope the rules give you before you draw a line of your own. In a GhPython component, wire in plot (the site outline), boundary (the Grenzabstand) and height_cap:

import Rhino.Geometry as rg
c = rg.AreaMassProperties.Compute(plot).Centroid
inner = plot.Offset(c, rg.Vector3d.ZAxis, boundary, 0.01, rg.CurveOffsetCornerStyle.Sharp)[0]
a = rg.Extrusion.Create(inner, height_cap, True)

The output a is your plot’s Kowloon volume, drawn by nobody. Send it to Archicad through the PAZ Grasshopper↔Archicad Library and colour the faces your scheme touches: the code drew those lines.

The copy on the footprint

The city was demolished in 1993–94. The 31,000 m² Kowloon Walled City Park that replaced it kept the yamen, the South Gate remnants and two 1802 cannons, the only original fabric left. Since May 2025 the yamen area has hosted a free open-air exhibition of full-scale set recreations from Soi Cheang’s 2024 film Twilight of the Warriors: Walled In: 1980s alleys and shops, down to a bone-setting clinic. TTG Asia calls it the largest of its kind in Hong Kong.

If Kowloon is on your route before May 2028, walk through the set, then visit the yamen. The image of the city now stands on the footprint of the city. Cyberpunk has closed its own loop.