Ancient China King Yong of
Zhao (posthumously known as the "Wuling" or "Martial-and-Numinous King") invaded and conquered the lands of the
Loufan (
t s Lóufán) and "
forest nomads" (
Línhú) tribes of modern northern
Shanxi 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, 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. Yanmen itself was defended, but by a fort and garrison on a local hill.
Imperial China At some point during the reign of the
First Emperor of
Qin (221–210BC), a
Chu noble named
Ban Yi ( or
Bān Yī) fled north to the
Loufan near Yanmen. By the
early Han Dynasty,
his clan had grown rich through
herding and trading thousands of heads of cattle and horses, to the point that they may have formed a microstate of their own. The example of their success encouraged greater Chinese settlement of the frontier around Yanmen. The markets were not always safe: In the fall of 129BC, 40,000 horsemen of the
Han Empire massacred the
Xiongnu trading at markets along the frontier; (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 or the year after, 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. 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. Under the
Ming, it was reconstructed as part of the
Inner Great Wall in 1374 and these are the defensive works seen today. It is one of the few stone stretches of the wall left in Shanxi.
Modern China During the
Second Sino-Japanese War (the Chinese
theater of
World War II),
He Bingyan led the 716th Regiment of his 358th Brigade of
He Long's 120th Division of the
Eighth Route Army in an ambush on the
Imperial Japanese Army forces at Yanmen Pass on 18 October 1937 as part of the ongoing
battles of Xinkou. The regiment claimed to have killed or wounded more than 300 Japanese troops and destroyed more than 20 vehicles at a cost of 112 casualties, then held the area as part of an attempt to cut Japanese lines of supply and communication as they
pushed forward to Taiyuan. 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. The Japanese were then obliged to begin
air assaults and dedicate the
Ushiromiya Division to push He's men further north. 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. ==Administrative divisions==