In China, interlocking puzzles are known as “Lu Ban locks” (Lu Ban suo 鲁班锁) or “Kongming locks” (Kongming suo 孔明锁). The assembled puzzles form a variety of geometrically pleasing structures and have traditionally been made from wood, bamboo or ivory. Some are shaped like smooth balls, while the interlocking pieces of others stick out, making the assembled puzzles look like burrs—the prickly seed cases that cling to clothing. These burr-shaped interlocking puzzles are known in the puzzle world as “burr puzzles.”
Interlocking Burr Puzzles and Chinese Joinery
Lu Ban (507–440 BCE) lived in the Spring and Autumn period (771–476 BCE) and is credited with the invention of the saw, the carpenter’s plane, and the ink line for marking straight lines. He is considered to be the patron saint of carpenters and the original master of wood joinery. Kongming was the brilliant strategist Zhuge Liang (181–234), prime minister of Shu Han in the Three Kingdoms period (220–280).
It’s true that burr puzzles share some characteristics with traditional Chinese joinery, which was first used in the construction of buildings and later in furniture making. The components of burr puzzles fit together by means of hidden joints, and they stay together without the use of glue or nails, allowing them to be easily taken apart and reassembled. However, there’s no evidence to attribute the invention of these puzzles to either Lu Ban or Kongming.
The interlocking burr puzzle with the simplest construction uses three sticks that can be assembled into a three-way cross in which each stick is perpendicular to the other two. The most common design uses three pairs of sticks, with each pair perpendicular to the other two pairs. But Chinese burr puzzles can have any number of sticks.
The sticks intersect each other, but they are also interlocked so that they stay together without easily coming apart. One way to accomplish this is by cutting a notch in the center of each stick in such a way that the pieces can be assembled without leaving a void inside their intersection. When the lock structure is almost assembled, the last stick (an unnotched piece called the “key”) is slid into place. Easy to take apart, interlocking burr puzzles require much patience and an understanding of spatial relationships to put back together.
Tang Yunzhou’s Interlocking Burr Puzzles
Tang Yunzhou described a six-piece burr puzzle locked together using an unnotched piece in his classic 1889 magic book Chinese and Foreign Magic with Diagrams: Compilation of Magic:
Interlocking burr puzzle from Compilation of Magic by Tang Yunzhou, 1889
Problem: Given six wood square sticks notched in the center, put them together at the notches to make a double cross. Like the “deer antler” obstacles placed in front of military camps, the pieces are put together to form one structure. However, once they are apart you will have difficulty putting them together if you don’t know how. It’s an intelligence-enhancing toy, just like tangram and nine linked rings. It came from magicians, but now it’s being sold as a children’s toy in the market. So finding its origin is not possible.
Solution: Use six pieces of blackwood [hongmu], each about 2 cun [6.4 cm] long and with square sides of 2.5 fen [0.8 cm]. Notch out each stick as shown in the diagrams. Then put the pieces together one at a time [from right to left], and you’ll be able to do it. Some pieces have to be placed horizontally or vertically. Match the pieces with their character numbers in the diagram to make them fit together.
The “osmanthus ball” from More Compilation of Magic by Tang Yunzhou, ca. 1890
Other six-piece burr puzzles may look identical to the one shown above when assembled but have a completely different locking structure. For example, the final locking stick may have to be rotated instead of being slid into place. Other interlocking burr puzzles may have seven, nine, twelve, eighteen, or more sticks—or they may have different shapes. Ball-shaped interlocking puzzles are especially popular.
Tang Yunzhou described a ball-shaped puzzle in a 1890 sequel to his famous magic book. He called it the “osmanthus ball” because of its resemblance to the flower of that name. He wrote, “The six-stick burr consists of six square wood sticks, while the osmanthus ball consists of half-circle wood pieces that form into a ball. While one of the six stick pieces is not notched and is the last to go into the burr to make the structure sturdy, the osmanthus ball pieces are all notched and look very similar, so it is not obvious which piece to remove first. Even if Lu Ban comes back to life, he won’t try to take it apart.”
Interlocking burr puzzles were popular in Europe as far back as the 17th century, but, as in China, there is no clear evidence as to when or how they originated.
Interlocking Burr Puzzles As Practical Objects
Yarn winders Shanxi province, 19th–20th c.
Interlocking burr puzzles have striking similarities to the construction and joinery of Chinese furniture, which itself drew on the principles of Chinese architecture. Traditional Chinese joinery never used nails, and glue was used very sparingly. As a result, furniture could expand and contract with changes in humidity, and it could be “knocked down” for storage or travel and then reassembled with little more that a mallet.
It is possible that burr constructions were used as practical objects before they became popular as puzzles. One example of this is the use of three- and six-piece burrs as yarn winders by women in the countryside of Shanxi province. While a carved piece of wood was commonly used to wind lengths of yarn, it could only accommodate one or two colors at a time. But a burr yarn winder with its six carved extensions allowed women to have all the basic colors at their fingertips. The joints of most burr yarn winders are very tight, so it’s unlikely that they were also used as puzzles.
Small wooden balls were also constructed using joinery. Some were meant to be played with as puzzles, but others were made to be worn as toggles or to be rotated in one’s hands as exercise balls.
Joinery was also used to construct the frames of traditional bamboo chopsticks holders. People hung these utilitarian containers on their kitchen walls to hold the family’s clean chopsticks between meals. Frequently they were decorated with sayings or slogans that give clues as to their age. The frames were constructed while the bamboo was still wet and pliable, and thin bamboo and wood panels were inserted between the frame members to create open-topped compartments to hold the chopsticks. As the bamboo dried out, the joints became very tight and impossible to disassemble. Open-top boxes and large lanterns were made in the same way.
Read More
Peter Rasmussen, Wei Zhang, and Niana Liu. Zhongguo chuantong yizhi youxi (Traditional Chinese Puzzles). Beijing: Sanlian Shudian, 2021. See pages 226–255. In Chinese.
