Introduction to the South Gate: The South Gate of the Imperial Mausoleum is the oldest, highest-level, largest, and best-preserved Sanchuque site that has been excavated so far. Its excavation has shed light on the origin, development, and system of the gate. It plays an important role in the formation, influence and research of ancient Chinese architectural history. In addition, the earliest brick Go board discovered so far, a ceramic ridge beast, and the largest slab tile were also unearthed from the Nanquemen site.