Illustrated Explanation of the Record of Trades: Volume I

How could the various explanations possibly differ? If we carefully interpret the classic text, it says: “Use its length to determine its circumference.” This refers to moving from the longitudinal grain The vertical or straight grain of the wood. to the transverse grain The horizontal or cross grain of the wood..

The text then says: “Using one-third of the circumference to cover the hub.” This refers back to moving from the transverse grain to the longitudinal grain.

It further states: “Divide the length of the hub into five parts: remove one part to determine the xian; remove three parts to determine the zhi.” This again refers to moving from the longitudinal grain to the transverse grain.

These measurements are interconnected and follow one another; thus, we can better appreciate the brilliance of the ancients' technical writing. If the text later explicitly describes the circumference of the xian and zhi The larger and smaller openings of the hub. while previously providing a separate, conflicting diagram, the ancients would never have been so inconsistent or contradictory. It is only because later scholars misunderstood the meaning that they have failed to reconcile the literary style, the philological training xungu: the traditional Chinese method of textual criticism and exegesis, and the mathematical proportions of the piece.

From the spokes inward is the large opening; from the spokes outward is the small opening. The large opening is the xian, and the small opening is the zhi.

An opening chuan: literally a "piercing" or "bore-hole" through which something passes is that through which the axle is threaded. The large opening is located on the side of the hub inside the spokes, near the carriage body The "yu," or the rectangular box where passengers sit.. The other is named the small opening.