Architecture
The lóngmén of Hong Kong: why some skyscrapers have a hole in the middle
“Dragon gates” are one of those rare cases where an ancient belief, a modern environmental rule and a structural calculation arrive at the same form.
Arriving at Repulse Bay, on the south coast of Hong Kong Island, you look up and see something surprising: a thirty-seven-storey building with an empty rectangle in the middle, as if someone had cut out a piece of the building to let the sky through. Locals call it a lóngmén, 龍門, “dragon gate”. And there are others: Hong Kong has a collection of pierced towers, and the explanation that has circulated for decades is among the most enchanting in contemporary architecture — the hole lets the dragon come down from the mountain to drink at the sea. The true story is more layered, and for that reason more interesting. It involves an ancient cosmology, a colonial legacy, an urban ventilation problem and some of the toughest structural challenges an engineer can face.
The tradition: mountain, water and the dragon vein
Feng shui (風水, literally “wind and water”) is a system for reading landscape that goes back more than three thousand years. In its symbolic geography, mountain ranges are the bodies of sleeping dragons and their ridges are “dragon veins” (龍脈, lóngmài), channels along which qi, the vital energy, flows. Qi generated in the mountains must reach the water to complete the cycle. A building placed between mountain and sea interrupts the flow; the dragon gate solves the problem with an elementary gesture: it opens a passage. Hong Kong is the ideal place for this geometry. It is a strip of vertical city compressed between the hills — Victoria Peak, Violet Hill, the mountains behind Pok Fu Lam — and the sea: nearly every residential tower on the coast stands exactly where the theory asks for a passage.
The history: why here
There is a historical reason why feng shui is more visible in Hong Kong than in any other Chinese city. During the Cultural Revolution (1966–1976), mainland China suppressed traditional practices, feng shui included. Hong Kong was a British colony, and the practice continued uninterrupted, entering the city’s real-estate culture as one consultancy among others, on a par with legal or structural advice. The big banks, the hotel chains and the colonial government itself consulted feng shui masters before building. The most famous case is the rivalry between Norman Foster’s HSBC headquarters (1985) and I. M. Pei’s Bank of China Tower (1990), whose triangular edges were read as blades pointed at the city; two cannon-shaped structures appeared on the HSBC roof, aimed at the rival tower. Whether or not the energy battle was real, the episode says how seriously the city takes these things.
The Repulse Bay: the archetype, and the surprise
The building that made dragon gates famous is The Repulse Bay, completed in 1989 on the site of the old 1920s Repulse Bay Hotel. Four towers of different heights, drawn to follow the profile of the hills behind, and in the tallest block the great rectangular void; the project received the silver medal at the Hong Kong Institute of Architects’ annual awards. Here comes the surprise: the owners told Tatler Asia that the dragon legend arrived afterwards — the void was born as an architectural choice, and the feng shui reading consolidated later, becoming part of the building’s identity. The same account emerges from a 2018 CNN investigation into the city’s pierced towers. Hong Kong’s most photographed hole is thus a case of tradition adopting a piece of architecture. Which makes it all the more real: in Hong Kong, where feng shui sells apartments, an opening oriented mountain-to-sea is a promise buyers recognise, and a building that keeps it carries symbolic value too.
Other well-known examples: the Residence Bel-Air towers at Cyberport, between the Peak and the Lamma channel, with several openings in sequence; Highcliff and The Summit on Stubbs Road, among the tallest residential buildings in the city; and various towers along Pok Fu Lam and the Southside. In every case the gate sits in the upper band of the building, facing the sea.
The present: the dragon and the wind ask for the same thing
If the explanation were only spiritual, dragon gates would be an eighties flourish. Instead they keep appearing, and the reason is that Hong Kong gave a modern name to a problem the tradition described in other words. It is called the wall effect: continuous rows of tall towers form a barrier that blocks the sea breeze, traps heat and pollution in the districts behind and sharpens the urban heat island. After years of residents’ campaigns and ventilation studies, in 2011 the Buildings Department introduced the Sustainable Building Design Guidelines, tying floor-area concessions to requirements for building separation, permeability and air paths. A passage through the building is one of the most direct answers. The feng shui master speaks of qi, the environmental engineer speaks of airflow, the developer wants the project approved and the flats sold: the gate satisfies all three. And there is an advantage that speaks for itself — behind a tower with a hole, the homes in the next row see the sea. In a city where a view is worth a solid share of the price per square metre, the opening is also a way of distributing value.
The technique: what removing a piece of skyscraper really means
Here lies the part that makes these towers extraordinary, and expensive. A tall building is a machine for carrying loads to the ground and resisting wind. A hole at mid-height touches both.
- Load transfer. The columns and walls that should run continuously from roof to foundations stop above the void: all the weight of the upper floors must be collected and diverted around the opening with transfer structures — wall-beams a full storey deep, Vierendeel frames with rigid joints and no diagonals so windows can pass, or entire floors turned into a bridge. Enormous elements, with reinforcement so dense that pouring the concrete becomes precision work.
- Wind and typhoons. Hong Kong designs for gusts above 200 km/h. A void in the facade changes how wind wraps the building: it can reduce lateral thrust, and at the same time creates local accelerations in the opening, vortex shedding and pressure differences between the two faces. You need a wind tunnel, more than a formula.
- Stiffness and torsion. Floor slabs work as horizontal diaphragms distributing wind forces to the cores. A slab interrupted by the void is a diaphragm with a hole: stiffness drops exactly where the building is already flexible, and if the hole is off-axis the tower tends to twist. You compensate with stronger cores, thicker walls, stiffening floors above and below the opening.
- The construction site. Transfer structures stay propped until the concrete reaches strength; the floors above rise only once the “bridge” holds. The construction sequence slows, the formwork is special, and the concrete’s long-term deformations must be calculated months ahead.
- The value of empty space. In a city with some of the world’s most expensive square metres, every floor left open is a weighty choice. That is why the 2011 guidelines are decisive: by tying floor-area concessions to permeability, they made the gap a piece of planning currency too.
Put together, these five points explain why a dragon gate appears only on the most ambitious towers: it is an engineering luxury, and like every luxury it says something about who can afford it.
Why all this matters
Dragon gates are one of those rare cases where an ancient belief, a modern environmental rule and a structural calculation arrive at the same form. And that is what makes them important beyond the tourist anecdote. They say a place’s culture can enter the building code under other names. They say constraints — wind, heat, density — produce more memorable architecture than freedom does. And they say a gap, the absence of something, can be the most expensive, most difficult and most meaningful part of a building. Looking at the Hong Kong skyline you can choose to see the dragon or the ventilation corridor: the buildings were designed to hold both readings.
Photo credits: all photos under the Unsplash License — Manson (cover), Florian Wehde (two photos), Simon Zhu, Ruslan Bardash, Sébastien Goldberg, Natalya Letunova, Robert Bye.
