Lanma Wall

　　Lanma Wall, in the northeast of Baixin Town, about

　　4

　　kilometers from the town, is a deep valley basin through which the Sancha River flows. To the east, the towering Gaotun Mountain and to the north, the forest-covered Sanguozhuang stand with towering trees. Sanguozhuang gets its name from the three peaks on its summit that resemble the legs of a tripod. This is the ancient Lanma Wall of the Shuixi region. It was also a key strategic defensive barrier built by Ankun in the northeast of Baini Tun to resist Wu's army. The *Dading County Annals · Historical Sites* records: “Lanma Wall is located 250 li west of the city, built by the Tusi Ankun of Baini Tun.”

　　Lanma Wall stretches between Gaotun and Sanguozhuang. In the third year of the Kangxi reign, Ankun ordered his troops to build it using rough stones, some weighing over a thousand jin. The wall is

　　200

　　meters long,

　　5

　　meters high, and

　　3

　　meters thick. It was not mortared with lime and features three arched gateways. The distance between each arched gateway is

　　60

　　meters, with the middle one slightly higher, forming a “品” (Chinese character for “eight treasures”) shape with the two side gateways. Below, water gates were constructed, fixed on both riverbanks with strip stones, and wooden planks were placed in slots like a drawbridge, allowing them to be raised or lowered to block or release water. Both the arched gateways and the water gates were built with finely chiseled strip stones.

　　On Gaotun Mountain, there is a square cave that could accommodate a hundred people. It is surrounded by stone walls with a gated entrance. There are two pathways, accessible along a small path to the left of Lanma Wall. Watchtowers were also built, housing wooden logs and rolling stones—structures made of wood and stone. When enemies approached, these logs and stones were released from above to injure or kill them.

　　After Wu Sangui suffered a defeat at Hou'er Pass, he redeployed a unit that broke through Lanma Wall and invaded Baini Tun. However, Ankun had already been alerted and reinforced defenses. When Wu’s forces arrived, fierce battles erupted before the pass. Wu’s army bombarded Sanguozhuang, causing rocks to fall down the mountain and crush an entire village, burying its inhabitants. Enraged, Ankun ordered the water gates to be opened, flooding and drowning over a thousand of Wu’s soldiers.