Yizhang

It is not easy to clarify the exact length of "one zhang" in ancient times. The standards of "zhang" used in different dynasties, different regions, and even different craftsmen may vary. Although there are many records in the literature, the lack of standardized measurements makes the calculation process full of variables. Therefore, it would be inaccurate to assert that "one zhang" is equivalent to a specific number based on a single document or record. Only by deeply studying the measurement systems of different periods can we understand the ancient measurement concepts more accurately.