According to local legend, the pirates, bare-chested and painted with totems, brandishing curved swords and scaling the walls of Meihua with ladders. The men of the fortress lit beacons, signalling the alarm while repelling the attackers with swords, bows and arrows, and stones.

Meanwhile the women of the fortress, hoisted pots to the top of the walls, filled them with water, then built makeshift stoves from stones to heat the water. As the enemy scaled the walls, they doused them with the scalding water, sending the pirates howling and tumbling off the ladders. Some even added pig feed to the water to make the boiling liquid even stickier and more damaging.

While official Chinese records often skim over such details, the stories told from person to person are prone to exaggeration. So to find out how the Meihua Fortress has held strong for five centuries, scientists took a deep dive into its layout and construction. They discovered that the designs at the fortress’ key points not only lent credence to the folktales, but also conformed to the optimal results calculated by computers.

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Lost, ancient Chinese Bodhisattva statue found in French home

Lost, ancient Chinese Bodhisattva statue found in French home

The team, led by Professor Lin Zhisen from Fuzhou University’s school of architecture and urban planning, analysed four wells within the fortress.

Using geographic software, they calculated water transport costs based on terrain and slope, mapping out the accessibility and suitability of the wells.

“The optimal service range of the wells extends from the east to the west gate,” Lin and his colleagues wrote in a peer-reviewed paper published in the Chinese academic journal, Landscape Architecture, in April.

“[These wells] not only meet the needs of daily life but also contribute to fire prevention and security,” Lin’s team said.

These pirates looted and burned villages, turned markets into ruins and left houses empty. More than a million people were killed or wounded.

To counter the constant raids by the Japanese pirates, the Ming dynasty bolstered its naval forces. They built 16 forts along the Fujian coast, across four prefectures, and added 45 inspection stations, recruiting more than 15,000 soldiers. Meanwhile, they fortified the coasts of eastern and western Zhejiang, constructing 59 forts and stationing troops at various outposts.

The Meihua Fortress underwent several renovations, evolving from a rural defensive settlement to an urban settlement. Parts of the north, east and west walls remain today, along with many ancient temples, ancestral halls and traditional houses, preserving the ancient streetscape.

The fortress is encircled entirely by a wall, its interior rammed earth, its exterior grey granite, camouflaging it from enemies, according to Lin’s team.

The thick walls made the pirates’ weapons, such as Japanese swords and arrows, useless. Gate towers, battlements and enemy platforms helped with the defence, providing cover and attack positions.

The Meihua Fortress has the Min River to its north, and the settlement clusters around Guishan, or Mount Turtle, a coastal peak. From its summit, the surrounding mountains, islands and river estuary can be seen, making it a prime reconnaissance post.

Summer is the rainy season when heavy rains can often lead to flooding. Therefore, flood control, drainage and moisture-proofing were paramount in the construction of the fortress. Lin’s team analysed the slope using Digital Elevation Model (DEM) data and found a gentle gradient ranging from 0 to 18.4 degrees. This slows rainwater flow, reducing the risk of landslides and other disasters.

Houses cluster along the mountainside, particularly on the northwest foothills of Guishan, where the terrain is flat and fertile, ideal for farming and settlement growth, enabling rapid military mobilisation, according to the researchers.

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Trove of porcelain pieces recovered from over 700-year-old shipwreck in waters of Chinese coast

Trove of porcelain pieces recovered from over 700-year-old shipwreck in waters of Chinese coast

Scientists also found that buildings are concentrated on the leeward side of Guishan, mainly facing northwest and west. Computer analysis suggested this is advantageous in blocking typhoons and monsoons that most often come from the southeast.

The sinking air current on the leeward side makes it difficult for clouds to form, reducing the frequency of rainfall during the wet season. It also facilitates the drainage of rainwater from higher elevation areas in the southeast to lower elevation areas in the northwest, avoiding flooding disasters.

Within the fortress, houses are interconnected, with residents favouring higher ground for platforms, thus bolstering defences.

Traditional homes have thick walls of rammed earth, dressed stone or brick, with lime plaster and sparse windows.

Large, solid stone foundations repel moisture. The multi-courtyard design offers enclosed exteriors and open interiors, enhancing privacy and defence.

Granite stone houses dot the landscape.

“Beams, columns, doors, windows and balustrades – all crafted from stone. Some entire houses and lanes are constructed of stone, sturdy and enduring, able to withstand the humid, rainy, typhoon-prone climate and enemy invasions,” the researchers said.

Stone walls encircle select buildings, acting as flood barriers and a buffer against invaders. Doorways are raised with thresholds and stone steps, preventing floodwaters from infiltrating.

The study of the Meihua Fortress “draws from a mix of human settlement science, history, military tactics, hydraulics, geography and more”, the researchers said.

“It offers valuable lessons for building resilient modern cities.”