Chinese woodworking craftsmanship---- Mortise and tenon joints (sǔn mǎo)

Mortise and tenon joints (sǔn mǎo) served as the primary structural method in ancient Chinese architecture, furniture, and other machinery. This connection technique involves interlocking protruding and recessed sections on two components. The protruding part is called the tenon (or tenon head); the recessed part is called the mortise (or mortise hole, mortise slot). 

In ancient China, mortise-and-tenon joints were employed both in architecture and furniture making. The framework of Chinese wooden structures typically comprises basic components such as columns, beams, crossbeams, base plates, purlins, bracket sets, rafters, and fascia boards. These independent elements require specific connection methods to assemble into a building. The “mortise and tenon” technique used to connect individual parts in Chinese furniture constitutes the primary structural method for shaping furniture. While various mortise-and-tenon techniques differ in application, each serves as a structural “joint” within the furniture's form. When executed properly, two wooden components fit together seamlessly, achieving a “perfect fit.” This technique was a fundamental skill for ancient carpenters, and the quality of a craftsman's workmanship was clearly reflected in the integrity of their mortise-and-tenon joints.

One type primarily joins surfaces to surfaces, though it can also join two edges together or connect a surface to an edge. Examples include the “groove tenon,” “rebate tenon,” “dovetail tenon,” “through-tenon,” and “mortise tenon.”

The second category involves structural methods functioning as “points.” These are primarily used for T-joints between horizontal and vertical members, angular joints, cross joints, and for extending straight or curved members. Examples include the “shouldered tenon,” “double tenon,” “double clamp tenon,” “hooked tenon,” “wedge-pinned tenon,” “half tenon,” and “through tenon.”

A third category involves constructing assemblies that connect three components together. Beyond employing some of the aforementioned mortise-and-tenon structures, these methods are more complex and specialized. Common examples include the “corner-support tenon,” “long-short tenon,” “shoulder-hugging tenon,” and “zong-jiao tenon.”

Tang Dynasty architecture exerted a profound influence on Japanese architecture. Beginning in the Nara period, Japan introduced the architectural style of China's Tang Dynasty, known as the Hakuhō style, which later evolved into the Japanese-style architecture through localisation. Subsequent generations of traditional Japanese architecture also retained many characteristics of Tang Dynasty architecture. Currently, most of China's extant ancient wooden structures are located in Shanxi Province.

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