【Haichuan Chemical Industry Site】Tianma Ancient Nitrate Processing Site in Cengong, Guizhou

The ancient nitrate production site is hidden in the depths of mountain cliffs. According to the former head of the county’s cultural relics management office, this site covers an area of over 20,000 square meters and was used for the production of nitrate in ancient times. Apart from the Daxiaodong nitrate production site in Liupanshui, this is the largest single-hole nitrate production site of its kind, and it is quite rare in China. The site is located in the hall at the entrance of Yunmendong, at the junction of Miaoluo Village and Yanwan Village in Tianma Town, as well as Muzhao Village and Heping Village in Dàyǒu Town. According to the Records of Sizhou Prefecture from the Kangxi era of the Qing dynasty, as well as the Compendium of Historical Geography, Yunmen Cave was originally named Quan Cave; it was also known as Hei Dong in local terminology. It received its current name after Cai Chao, a minister during the Ming dynasty, engraved the characters \"Yunmen\" on the rock. “Above are waterfalls, below is a clear pool.” “The rock cliffs are thousands of feet high, with waterfalls pouring down to form streams. ”“A boat can enter the cave from the side; it can accommodate a hundred people. ”It vividly describes the steep terrain and the uniquely beautiful scenery of this place.

Hundreds of people worked in the cave for nitrate production on a daily basis. In 2010, the cultural relics survey department of Cengong County conducted an investigation of this site and found that the entrance to Yunmen Cave was about 30 meters high and 50 meters wide, originally sealed off by earthen walls. The front hall inside the cave is even taller and more spacious; within this hall, which covers an area of over 20,000 square meters, there are dozens of piles made of yellow clay used for nitrate production, creating a truly spectacular sight. Among them, 14 piles are relatively well-preserved, with each pile covering an area of about 50 to 100 square meters. Its height varies depending on the terrain, ranging from 3 to 9 meters. Each pile is equipped with 5 to 8 nitrate-purifying pots, giving it a \"mushroom pile\" appearance from a distance. Although the nitrate-smelting pots have disappeared, the mud \"boilers\" used to support them still remain; these \"pits\" are filled with dust and trash left by visitors. Their diameter ranges from 1.2 to 2 meters, with the largest ones measuring 3 to 4 meters. Based on the scale of the site, experts estimate that around 100 or more people were employed at this nitrate production facility daily, with a daily output of over 300 pounds of nitrate.

The nitrate-processing mud left in the cave “boiler”

It may have been built during the Song or Yuan dynasties in connection with the Tusi regime. At the site of the Muzhao provincial-level cultural heritage protection unit in Dàyǒuzhen, there is a stele stating \"Prohibition on the Use of Gunpowder\". The head of the Cultural Relics Management Office said that from the inscriptions, he learned that the gunpowder production site at Yunmen Cave was built during the Song and Ming dynasties, and it was still in use during the Jiaqing period of the Qing dynasty. Such a large-scale nitrate production must be for military use; it is certainly not something ordinary people would do. It is likely that during the Song and Yuan dynasties, the Tian family’s tribal regime moved from northern Guizhou to Sizhou (present-day Cengong County), where weapons were manufactured in order to expand their territory. The “Medicine Yard,” located just 1.5 kilometers away from the sites where gunpowder was produced, may have served as a warehouse for storing such materials. Historical records show that during the Ming and Qing dynasties, local officials visited Yunmen Cave. “Cai Chao, a minister of the Ming dynasty, carved the characters ‘Yunmen’ into the stone. ”Based on this, scholars in the fields of history and culture believe that the Yunmen Cave nitrate production site was an ancient \"underground military factory.\" Cai Chao, a government official in Guizhou during the Ming dynasty who was in charge of military affairs, must have gone to the remote and dangerous Yunmen Cave not for the scenery, but likely to inspect this \"underground military factory.\" “Due to the chaos caused by the retreating troops, many gentlemen from the local area took refuge there. ”Once again, it is evident that during times of turmoil, the officials and elites of Sizhou Prefecture fled to Yunmen Cave, located 50 li north of the prefecture, to take shelter there; this shows that Yunmen Cave had sufficient **security measures in place to protect the lives and property of the prefecture’s officials and wealthy individuals. Scholars in the fields of history and culture say that the Yunmen Cave nitrate production site is a precious ancient cultural heritage site. The production of nitrate was one of the four great inventions of ancient China, with far-reaching impacts. This site holds great value and significance for studying the history, politics, and other aspects of Cengong and the southeastern Guizhou region during the Song, Yuan, and Ming dynasties.