The 48th World Skills Competition opens in Shanghai, with a stunning appearance of mortise and tenon elements

On the evening of the 22nd, the 48th World Skills Competition officially opened on the Huangpu River. On the stage, a huge Luban lock slowly closed. At that moment, the world's attention focused on this.

Outside the stage, this "lock" can actually be seen everywhere in this city - it is in the World Championships LOGO, the countdown device in the subway station is spelled out with it, Chinese players have it embroidered on their award uniforms, and even the medals of this competition have it engraved on the front.

It's called mortise and tenon.

Regarding mortise and tenon joints, the most common picture that comes to mind is this: a piece of wood protrudes, and another piece of wood is recessed. The two snap together, and they can fit tightly without nails or glue.

Depending on the location, force direction, and structural requirements of the components, craftsmen have created hundreds of mortise and tenon forms over thousands of years. From the most basic straight tenon and dovetail tenon, to the complex angle tenon, wedge tenon, chuck tenon, and raglan tenon, to the complex stacked and interlaced structures in the building brackets, each type of mortise and tenon is an ingenious answer to a specific problem.

Judging from archaeological discoveries, this craft can be traced back to more than 7,000 years ago. Hundreds of wooden components with mortise and tenon joints were unearthed from the Lan-style architectural remains at the Hemudu site.

The mortise and tenon joint is even older than the name "mortise and tenon joint". In ancient times, it was called "chisel". Sima Qian wrote in "Historical Records: Biography of Mencius and Xunqing": "I hold a square skewer and want to chisel it inside, but can it get in?" - Holding a square tenon and poking the round eyelet, can it be inserted?

It was not until the Song Dynasty that the word "mortise and tenon" gradually changed from spoken language to written language.

What have the mortise and tenon held up in these seven thousand years?

The wooden pagoda in Yingxian County, Shanxi Province, is about 67 meters high, equivalent to more than 20 floors. In 2016, the Guinness World Records certified it as the tallest wooden pagoda in the world. The tens of thousands of wooden components throughout the tower are all held together by mortise and tenon joints, and they have survived many strong earthquakes.

The Forbidden City in Beijing (Forbidden City) is the largest and best-preserved wooden palace complex in the world. It has withstood more than 600 years of wind and rain and withstood the test of more than 200 earthquakes, and it has always stood firm. The secret of its durability lies in the flexible structure constructed of mortise and tenon joints and brackets.

When an earthquake strikes, the mortise and tenon joints do not resist with rigidity, but through tiny displacements and frictions, the shock wave energy is dissolved layer by layer, just like Tai Chi Push Hands, which softens the rigidity and invisibly relieves the tremendous force. From the wooden pagoda in Yingxian County to the Hall of Supreme Harmony in the Forbidden City, from the folk houses in the south of the Yangtze River to the royal altars and temples, the bones and muscles of ancient buildings all depend on these invisible "joints".

Behind this is the Chinese people’s view of creation. Wood will expand with heat and shrink with cold, and metal nails will damage the wood, so the ancients chose to solve the problem by following the temperament of the material. One convex and one concave, one yin and one yang. As the "Book of Changes" says, "one yin and one yang are called Tao": the protruding tenon is yang, and the concave mortise is yin. They bite and restrict each other, while leaving room for each other.

In the World Games LOGO, the mortise and tenon joints are the core visual symbols.

The countdown device for the World Championships at People's Square Station of the Shanghai Metro is a "woodwork" built with mortise and tenon joints: it is assembled and fitted without any nails or rivets.

According to the official introduction, "the mortise and tenon joint represents a stable structure formed by precise engagement of two independent components, which is essentially a kind of wisdom of 'connection'"; in today's highly developed digital technology, this connection "transcends the physical level of wood and wood, and sublimates into the connection between people and people, skills and skills, skills and the world, culture and region, tradition and the future".

The medal also chose mortise and tenon joints. The medals for this year's World Championships are manufactured by Shanghai Mint Co., Ltd., and the leading designer is "Shanghai Craftsman" and senior arts and crafts artist Zhu Xihua. Zhu Xihua introduced that the design team has tried blue and white porcelain inlay, enamel, glass inlay and other solutions. It took about a year from idea to finalization, with dozens of drafts revised, and finally the mortise and tenon joints were finalized.

Zhu Xihua said: "The mortise and tenon structure itself is very interesting. It has a sense of combination, structure, and closeness, and it is more consistent with the spirit of craftsmanship." His biggest problem is "how to make international friends understand the meaning of the medal in a small space, and also feel refreshed."

The front of the medal is based on the structure of Luban Lock, making it the first irregular hexagonal medal in the history of the World Championships; the back is the Shanghai Shikumen lintel and the Pudong skyline. The design also won recognition from WorldSkills.

Mortise and tenon joints are also worn on Chinese players. The prize-winning uniforms and competition uniforms of the Chinese delegation in this competition all invariably extracted design elements from the mortise and tenon structure.

The award-winning uniform is "Red Shows Ingenuity, Building Dream World Championships", the men's red tie is woven with a mortise and tenon pattern, and the women's clothing is matched with a mortise and tenon dark pattern silk scarf; the competition uniform is "Blue Shows Ingenuity, Racing to the World Championship", with abstract geometric patterns of mortise and tenon structure on both sides of the shoulder sleeves.

In previous World Championships, mortise and tenon joints also appeared "across the circle". When the 47th WorldSkills Competition concluded in Lyon, France, teachers and students from Donghua University amazed the audience with 20 sets of paper art costumes designed by themselves. More than half of these 20 sets of costumes used construction mortise and tenon technology.

Transplanting the mortise and tenon structure in architecture to clothing can be said to be an innovation. Clothes that use mortise and tenon technology have a strong three-dimensional effect and are "very crisp," said Zhang Zufang, a professor at the School of Fashion and Art Design at Donghua University and the leading designer of "Paper Art Chinese Clothing". In addition to mortise and tenon technology, carving, origami, 3D printing and other technologies were also used in the design. These clothes, paired with lights, are full of technology.

On a broader level, mortise and tenon joints are becoming a window for foreigners to understand China. In recent years, with the help of social platforms such as TikTok, videos of mortise and tenon joints have gained a lot of attention overseas, and many foreign young people have learned about Chinese woodwork for the first time.

According to Wang Zhenhua, an inheritor of miniature ancient building construction skills, many people summarize the mortise and tenon joint as "concave and convex", which means they flatten the mortise and tenon joint: "The mortise and tenon joint as I understand it is a traditional Chinese engineering technology system and a creative way of thinking. It also contains strong Chinese philosophical thoughts and is flexible and adaptable to local conditions."