Yanmen Pass

King Yong of Zhao (posthumously known as the "Wuling" or "Martial-and-Numinous King") invaded and conquered the lands of the Loufan (t 樓煩, s 楼烦, Lóufán) and "forest nomads" (林胡, Línhú) tribes of modern northern Shanxi[8] in 306 and 304 BC. He organized these conquests as the commanderies of Yunzhong, Yanmen, and Dai and, by around 300 BC, had begun erecting earthen defensive works to protect his new holdings from other nomads from the Eurasian steppelands.[8][9] Although Zhao's Yanmen Commandery was named after the pass, whose premodern importance for accessing the valleys of central Shanxi caused it to be scene of many battles throughout Chinese history,[1] the ramparts raised under King Yong did not run through it but along the northern extent of his territory closer to today Hohhot in Inner Mongolia.[10][11] Yanmen itself was defended, but by a fort and garrison on a local hill.[1]

At some point during the reign of the First Emperor of Qin (221–210 BC), a Chu noble named Ban Yi (斑 or 班壹, Bān Yī) fled north to the Loufan near Yanmen.[12] By the early Han Dynasty, his clan had grown rich through herding and trading thousands of heads of cattle and horses,[13] to the point that they may have formed a microstate of their own.[14] The example of their success encouraged greater Chinese settlement of the frontier around Yanmen.[13] The markets were not always safe: In the fall of 129 BC, 40,000 horsemen of the Han Empire massacred the Xiongnu trading at markets along the frontier;[15] (The heavy defeats of Li Guang and Gongsun Ao near Yanmen, however, had them narrowly escape execution through the payment of large fines and their demotion to common status.) The next year[16] or the year after,[15] Wei Qing and 30,000 men rode north from Yanmen and defeated the Xiongnu left in the area,[16] taking control of the entire Ordos Loop.[15] 100,000 Chinese were sent to colonize the area.[15] In 127 BC, the Xiongnu defeated and killed the governor of Liaoxi; Han Anguo (t 韓安國, s 韩安国, Hán Ānguó) tried to hold them near Yanmen with 700 men but was defeated and forced to withdraw to Yuyang.[17] Wei Qing and Li Xi returned to the area in force, capturing some Xiongnu and forcing the rest to withdraw beyond the frontier.[17] The Ban clan ultimately left the tumultuous area and used their accumulated wealth to rise to prominence among the officials of the Eastern Han by the 1st century AD.[18]

A line of the Great Wall was finally built through the pass by the Northern Qi in AD 557.[19] It was part of a massive public works project involving more than 1.8 million laborers ordered by the emperor Gao Yang (posthumously known as the "Wenxuan" or "Civil-&-Responsible Emperor"), intended to protect his realm from the inimical Northern Zhou.[19] As with the later Ming Great Wall, the Northern Qi's Yanmen wall formed an inner line of defense; it was repaired and expanded in 565.[19] Despite its strong defenses, the state itself fell into chaos and was consumed by the Northern Zhou in the late 570s. The retired emperor Yuwen Chan (posthumously known as the "Xuan" or "Responsible Emperor"), acting on behalf of his young successor Yuwen Yun (posthumously the "Jing" or "Silent Emperor"), refortified the wall between Yanmen and Jieshi in 579 to protect Northern China from the Blue Turks and the Khitans.[19] Upon Yuwen Chan's death in 580, his father-in-law Yang Jian seized power, eventually declaring himself the first emperor of the Sui.[19]

The Sui (581–618) rulers regarded the Great Wall as an essential line of defense and ordered large-scale repairs 7 times, but their successors the Tang (618–907) expanded China far to its north, and allowed it to fall into disuse and decay.[19] Following the collapse of the later Tang and its short-lived successor later Han of Five dynasties and Ten Kingdoms era, most of the lands around Shanxi were controlled from Taiyuan by Liu Chong as the Northern Han. Zhao Kuangyin (posthumously known as "Emperor Taizu" or "the Great Ancestor") unified most of China proper as the Song Empire prior to his death in 976, and his younger brother and successor Zhao Jiong (posthumously "Emperor Taizong", also meaning "the Great Ancestor") invaded the Northern Han in 978 and conquered it the next year. In 980, roughly 100,000 nomad horsemen of the Khitan Empire (known to the Chinese as the Liao) invaded Shanxi under their general Li Chonghui (t 李重誨, s 李重诲, Lǐ Chónghuì) and on behalf of their defeated allies. Arriving before Yanmen, Li and his men were encircled and catastrophically defeated by the Song generals Yang Ye and Pan Mei[20] outside the fortress at Baicao Lingkou.[21] The victory killed the Khitan emperor's brother-in-law Xiao Chuoli (t 蕭啜裏, s 萧啜里, Xiāo Chuòlǐ), won Song innumerable horses and war equipment, and secured its new conquests and northern border.[20]

Under the Mongolian Yuan Dynasty, the great khan nominally controlled the peoples on both sides of the wall and its fortifications were fallen into disrepair.[1] Under the Ming, it was reconstructed as part of the Inner Great Wall in 1374 and these are the defensive works seen today.[1] It is one of the few stone stretches of the wall left in Shanxi.[21]

During the Second Sino-Japanese War (the Chinese theater of World War II), He Bingyan led[22] the 716th Regiment of his 358th Brigade of He Long's 120th Division of the Eighth Route Army in an ambush the Imperial Japanese Army forces at Yanmen Pass on 18 October 1937 as part of the ongoing battles of Xinkou. The regiment killed 300 Japanese and destroyed 20 vehicles, then held the area as part of an attempt to cut Japanese lines of supply and communication as they pushed forward to Taiyuan.[23] There was also a skirmish during the night of 20 October, then an assault on a second supply column the next day. This supposedly took out around 200 Japanese and "hundreds" of vehicles.[23] The Japanese were then obliged to begin air assaults and dedicate the Ushiromiya Division to push He's men further north.[23]

Following the war, Yanmen Pass was reckoned as part of the boundary of China's "Third Front", which was used by national authorities in planning infrastructure investment and military defenses. Yanmen Township was created in 2001 from the merger of parts of some of Dai County's smaller settlements, particularly Shangtian and Baicaokou. The Yanmen Pass Scenic Area was named a AAAAA attraction by the China National Tourism Administration in 2017.[24]