The Lingqu Canal, also known as the Qin Ditch or Du River, is located in Xing'an County of Guilin City. It can be directly reached by National Highway 322 and is 60 kilometers away from the city center of Guilin. Built in the 33rd year of Emperor Qin Shi Huang (214 BC), it is called one of the three great water conservancy projects of the Qin Dynasty, along with Dujiangyan in Sichuan and Zhengguo Canal in Shaanxi, and is one of the oldest canals in the world. It has a history of 2200 years so far, playing an extremely important role in promoting economic and cultural exchanges between the Central Plains and the Lingnan region, and making indelible contributions to maintaining national unity and consolidating border defense.
In 221 BC, after Emperor Qin Shi Huang unified the six states, in order to complete the great cause of unifying China, he then "sent General Tu Gui to lead the naval troops to attack Baiyue in the south" and advance into the Lingnan region. The 550,000 Qin army was divided into five routes advancing towards the Baiyue land. Among them, the Qin army attacking Guangxi encountered fierce resistance from the local tribes, forcing the Qin army to remain on high alert for "three years without taking off armor" (Huainanzi: Renjianxun). Investigating the reasons for the unfavorable warfare, it had something to do with the Qin army's inability to adapt to mountainous warfare, being unsuited to the southern climate, and having many sick soldiers, but more importantly, the rugged terrain of the Lingnan region, long transportation lines, and insufficient supply of military provisions and grain. Solving the transportation of military supplies became the key to deciding the victory or defeat of this war. Emperor Qin Shi Huang decisively made the decision to "make Jian Lu dig a canal to transport grain" (Records of the Grand Historian: Pingjin Hou Zhufu Liezhuan). Under the direction of Shi Lu, after the hard work of the conscripted laborers and the Qin army, enduring several cold and hot seasons, the Lingqu Canal was successfully excavated. The Qin army's food and salary were transported by ship from the Xiang River through the Lingqu Canal into the Li River, continuously reaching the front line, ensuring the needs of the front-line military. In the 33rd year of Emperor Qin Shi Huang, the Qin army finally unified Lingnan, setting up Guilin, Nanhai, and Xiang Commanderies, and dispatching troops to garrison there. Thus, Emperor Qin Shi Huang completed his great cause of unifying the whole country.
The canal excavation technology of the Lingqu Canal achieved brilliant achievements in the history of ancient hydraulic engineering and still shines brilliantly today. Xing'an County is located in the northern mountainous area of Guangxi, surrounded by mountains and rivers. To the southeast stands the Dupo Ridge, one of the Five Ridges, while to the south lies the continuous Haiyang Mountain. To the northwest towers the Yuecheng Ridge. The prominent feature of the terrain is that the southeastern part is higher in the south and lower in the north, while the northwestern part is higher in the north and lower in the south. In the middle of Xing'an County, a lowland with an altitude of only about 200 meters has formed, which is the famous Xiang-Gui Corridor and has always been a major traffic artery leading from Hunan into Guangxi. Due to this terrain feature, the Xiang River, originating from Haiyang Mountain, flows northward to Xing'an County, follows the Xiang-Gui Corridor through Quanzhou County into Dongting Lake in Hunan; the Li River, originating from Miao'er Mountain, the main peak of the Yuecheng Ridge, flows southward to Rongjiang, passes through Lingchuan County and Guilin City, and joins the Xi River at Wuzhou, flowing into the Pearl River in Guangdong. The Xiang River flows northward, and the Li River flows southward, with opposite flow directions, hence the saying: "Xing'an is ten thousand feet high, water flows in two directions." The Xiang River and the Li River are within 25 kilometers of each other in Xing'an County, and it would have been quite difficult to directly excavate a canal connecting the two rivers in the Qin Dynasty. Fortunately, the Li River has a tributary named Ling River, formed by the confluence of numerous small streams, one of which is called Shian Water. Shian Water originates from Fugui Ridge near Xing'an, with a straight-line distance of only 2.5 kilometers from the Xiang River, separated only by a ridge over 300 meters wide and over 30 meters high, namely the Yuecheng Ridge (also called Shian Ridge or Linyuan Ridge), which is the watershed between the Xiang and Li Rivers. As long as this ridge is breached, the higher-altitude Xiang River water can be introduced into the Shian Water, thus connecting the Li River. After careful surveying, the smart designer at the time discovered this secret. Then the Qin army built a dam across the Xiang River to raise the water level, dug a 5-kilometer-long channel, and cut through Taishi Temple Mountain on the Yuecheng Ridge, introducing the Xiang River water into the Shian Water, and guiding and transforming the Shian Water to allow ships to pass through it into the Ling River and then into the Li River, thus connecting the Xiang and Li Rivers. According to historical records from the Tang Dynasty, apart from the channel, the Lingqu Canal already had large and small Tianping (i.e., plow-shaped dikes), Huamouth, Qin Dyke, flood discharge Tianping, sluice gates, etc., which are basically the same as what we see today. These structures are scientifically matched and closely connected, making the Lingqu Canal an immortal water conservancy project.