WANG Zhenhua, who rose to national prominence for miniature replicas of ancient structures made without using any nails or glue, has developed a building-block toy kit to introduce children to traditional Chinese mortise-and-tenon joinery, called sunmao.

The Shanghairesident, from Minhang District, is famous for his accurate model replicas of the 1,400-year-old Zhaozhou Bridge, the oldest standing arch bridge in China, and the Hall of Prayer for Good Harvests in Beijing, a six-year effort he calls a masterpiece.

The prayer hall was built on a scale of 81:1. The first toy model kit he made in collaboration with an arm of the electronics manufacturer Xiaomi is on a scale of 200:1, with nearly 900 components.

“The skills of ancient workers ensured that a house built with mortise-and-tenon joinery would never fall,” said Wang, noting that the technique of sunmao dates back 7,000 years.

The model kit, referred to as the “Chinese Lego” by local media, has been praised for its infinite building possibilities. Wang said he plans to offer more traditional Chinese buildings in the toy brand.

“Sunmao has no fixed structure and people can create their own locking ways,” Wang told Shanghai Daily. “It’s a wisdom of the East. It’s a very complex engineering system as vast as the sea.”

He added, “It is embedded with old Chinese philosophy, such as the harmony between man and nature. Although we have many variations of sunmao inherited from our ancestors, such as that used in furniture from the Ming (1368-1644) and Qing(1644-1911) dynasties, the idea of sunmao goes far beyond that. It’s a bit like the relationship between human beings — sometimes we have to keep away from each other, but at other times, we have to face things and bear them together.”

Born in 1958, Wang fell in love with ancient buildings as a boy. During his childhood, his family lived next door to a carpenter, and Wang played with the wood shavings. After graduating from middle school, he learned carpentry and the skills of restoring ancient buildings on his own. A few years later, he familiarized himself with nearly all mortise-and-tenon joinery systems.

After graduating from college, he worked as an engineer but never stopped reading books on ancient Chinese architecture. In 1986, he visited the Temple of Heaven in Beijing, a famed imperial complex. He was awed by the temple’s grand layout and elaborate structures. On the spot, he decided to create his own Hall of Prayer for Good Harvests before he turned 60 years old.

In 2010, he found a model of the hall at an exhibition, but its components were joined with glue and the windows didn’t open. It strengthened his resolve to make an authentic model of the iconic structure built in 1420.

“This building has a profound meaning to Chinese people,” he said. “It was built to pray for abundant harvests and the nation’s prosperity. The model had to not only duplicate the hall’s appearance but also reflect its inner ‘soul,’ such as mortise-and-tenon joinery.”

Wang rented a house in suburban Qingpu District as his workshop. It took him more than two hours for a round trip on his electric bicycle.

He used cheap steelknives to make more than 300 special modeling knives. The thinnest head of a knife is only 0.8 millimeters.

“It was impossible to use the original sunmao joinery on such a small scale, so I had to design one for it.”

He worked 10 hours a day, almost all year, spending considerable time traveling to the hall site in Beijing, looking up references, taking measurements, drawing sketches and making wooden components.

“Our ancestors were really smart,” Wang said. “In the Tang Dynasty (AD 618-907), they used ‘vision correction’ in the construction of buildings. For example, the two ends of the roof of an ancient building were generally upswept. To make the bottom of the roof look like a straight line, the workers made the upswept part rise layer by layer.”

He developed several versions of his model, perfecting a better joinery system each time. He burned old models and kept forging ahead. Sunmao requires great skill and accuracy to get the “tongue” of the tenon perfectly fit the “hole” of the mortise. The result is a very strong structure.

Wang’s family supported his work.

“My son said he believed that I would succeed, and my wife never complained,” he said.

In October 2015, the final version of the Hall of Prayer for Good Harvests was completed. Every tiny window on the model includes carving and can open. The model won top prize at the 2016 World Crafts Expo and has been valued at more than 10 million yuan (US$1.47 million), but Wang never entertained the thought of selling it.

The prayer hall replica contains 7,108 components. The components of the umbrella-shaped corrugated roof were connected with each other by a system called the Lu Ban lock.

Three years later, Wang’s second ancient structure miniature, the Zhaozhou Bridge, was completed. It is 50 times smaller than the real one in Hebei Province — 1,280 millimeters in length, 280 millimeters in width and 260 millimeters high. The toy replica could bear a weight of up to 40 kilograms if a person were to walk over it.

Wang used an interlocking “burr puzzle” for easy sliding and accurate fitting of the pieces.

Now Wang is planning for his third work, the Yellow Crane Tower, an iconic landmark in the Hubei Province capital of Wuhan.

Education tool

After his prayer hall model won the national prize, a foreign company sought to collaborate with Wang to create a toy version but asked him to drop his mortise-and-tenon system and use another joinery method. Wang refused.

Xiaomi later approached him with a toy project that would retain his system.

“There are many ways to master cultural heritage, such as apprenticeships or classes,” he said. “China is a large importer and exporter of building block toys. But there are few quality toy brands like Lego in the country.”

He added, “Sunmao is a system different from Lego’s linkage. To build a Hall of Prayer using Lego, it would take more than 100,000 building blocks and be a hard job for a child. But with sunmao, we can make the hall with only 877 components.”

When designing the toys, Wang encountered several difficulties, including the need to adapt locking systems to a small toy and the need to balance difficulties so that the structure assembly wouldn’t be too easy or too hard.

“We don’t give many detailed instructions in the instruction manual —just a few simple tips,” he said. “That prods parents to do some research on sunmao structures and share it with their children. It can be an education tool for all ages.”

Wang said he recalls a Beijing boy who spent a whole night trying to assemble a Hall of Prayer from toys.

“Another boy in Shanghai, who is only 6 years old and cannot read, finished the assembly in three days, based on his experience with Lego toys,” he said. “He told his mother that he likes my toy more because of the locking systems I designed.”

After a child has built a whole model, according to Wang, he will have learned a lot about the techniques used in ancient Chinese building.

With an increasing national focus on Chinese heritage, more toys using mortise-and-tenon joinery are appearing in the market. In a bazaar at the recent Shanghai Tourism Festival in September, a toy model kit for the Shanghai Tianhou Palace excited visitors, Wang said. It was developed by Shanghai Jiao Tong University’s International Research Center for Architectural Heritage Conservation and domestic firm Wanfeng.

The kit uses the traditional Jiangnan-style joinery called dougong, a bracketing system connecting column tops with crossbeams.

The university team has also published a brochure about stories related to the Tianhou Palace.

“We’re now responsible for the restoration project of the palace,” said Feng Li, who works with a design and research institute on historic buildings at the university. “During restoration, we found interesting structures and used 3D scanningto measure components. Dougong attracted us most, and we later incorporated it into the toy. It’s just a small and simple sunmao structure, and it only takes 15 to 20 minutes to complete the assembly.”

He said that using dougong allows people to appreciate the beauty of ancient construction.

Wang said it is important to make toys that are not only fun but also educational.