Ming Great Wall
[4] In 1373, as Ming forces encountered setbacks, Hongwu put more emphasis on defence and adopted Hua Yunlong's (華雲龍) suggestion to establish garrisons at 130 passes and other strategic points in the Beijing area.
[7] Yongle's reign also saw the rearrangement of the dynasty's frontiers that led to all but one of the eight outer garrisons being abolished to cut expenses, thereby sacrificing a vital foothold in the steppe transitional zone.
Over the late 15th and 16th centuries, the choice between the two options became the subject of fierce debate in the Chinese court and dissension that was sometimes exploited by various political factions to get rid of the opposition.
[15] As offensive action against the nomads became increasingly untenable due to a shortage of fighting men and military supplies, Yu Zijun (余子俊; 1429–1489) first proposed constructing a wall in the Ordos region in August 1471, but this went against the traditional offensive-based policies in place since the early Ming.
Minister of War Bai Gui (白圭) had tried to implement an offensive solution since taking office in 1467, and he objected to Yu's proposal because of cost fears.
The court and emperor approved the plan, and the 1473 victory in the Battle of Red Salt Lake (紅鹽池) by Wang Yue (王越) deterred Mongol invasions long enough for Yu Zijun to complete his wall project in 1474.
This wall, a combined effort between Yu Zijun and Wang Yue, stretched from present day Hengcheng (橫城) in Lingwu (northwestern Ningxia province) to Huamachi town (花馬池鎮) in Yanchi County, and from there to Qingshuiying (清水營) in northeastern Shaanxi, a total of more than 2000 li (about 1,100 kilometres (680 mi)) long.
This defence system proved its initial worth in 1482, when a large group of Mongol raiders were trapped within the double lines of fortifications and suffered a defeat by the Ming generals.
Starting from the 1520s, proposals were made to strengthen the defences of this region, but the plan was disrupted by the local populace's resistance to the prospect of labour; only in the 1540s did work proceed in earnest.
Detractors cited its high costs and the drain on military manpower as reasons for their opposition[31] and in 1557 the Grand Coordinator Wu Jiahui (吳嘉會) was jailed on charges of embezzlement due to faulty and wasteful wall-building.
"[32] In 1567 Qi Jiguang and Tan Lun, successful generals who fended off the coastal pirates, were reassigned to manage the Ji–Chang Defense Commands and step up the defences of the capital region.
They submitted an ambitious proposal to build 3,000 brick towers along the Great Wall, and manoeuvred their way out of political opposition through the efforts of their allies at the imperial court.
In contrast, the Ji–Chang towers built from 1569 onwards were hollow brick structures, allowing soldiers interior space to live, store food and water, stockpile weapons, and take shelter from Mongol arrows.
[13] On 6 July 1576, a minor Mongol raid broke through a small gap in the Wall and resulted in the death of several high ranking border officials in the vicinity of Simatai, 8 miles (13 km) east of Gubeikou.
As a result, the earthen defences around Beijing were torn down and replaced by ones built with stone bricks and sanhetu (三合土), an early sort of concrete made of lime, clay tiles, and sand.
After the Fushun garrison within the Liaodong Wall surrendered to Nurhaci the next year, the Ming court assembled a Chinese–Korean army numbering above 100,000 men to contain him, but they were catastrophically defeated at the Battle of Sarhu.
To drive the point home, Hung Taiji sent an army around Ningyuan through Mongol territories to breach the Great Wall pass at Xifengkou in the fall of 1629, taking advantage of a rift in the Ming ranks due to Yuan Chonghuan's execution of his fellow commander Mao Wenlong.
[39] Following Hung Taiji's raid, regular garrison troops in the western defence zones along the Great Wall were sent east to defend the capital, which had the unintended consequence of instigating more instability.
The regions of Shaanxi had already been afflicted by adverse weather, heavy taxation, and fiscal mismanagement, so the removal of a substantial military presence encouraged the inhabitants to turn to banditry and rebellion; the remaining garrison forces, already unpaid and resentful, saw little choice but to throw in their lot with the rebels.
[40] A prominent leader who rose from the ranks of the rebels was Li Zicheng, the self-titled "Dashing Prince" (闖王, Chuǎng Wáng) who came to dominate Central China by 1642.
"[46] In the first months of 1644, Li Zicheng, having consolidated control over his home province Shaanxi, declared himself the founder of a new Shun dynasty, and marched against the Ming court in Beijing.
[41] In this effort Li was met with next to no resistance as most garrisons surrendered to the Shun with no major fighting, except at the Ningwu Pass where the general Zhou Yuji (周遇吉) fought to the death.
[47] By April 17, both the major garrisons at Datong and Xuanfu had surrendered to Li Zicheng, and most Ming hopes were placed on the last Great Wall pass at Juyong and its defender Tang Tong (唐通).
[48] However, just as the Ming court was discussing the means of increasing provisions to Juyong Pass, it received word that Tang Tong had surrendered and let the Shun army through on April 21.
[51] Halfway to Beijing, Wu received news of Chongzhen's death, so he went back to garrison the Shanhai Pass, the eastern terminus of the main Great Wall line.
[52] On May 3 and May 10 Wu Sangui twice defeated the Shun vanguard led by the turncoat Tang Tong,[53] but he knew that his force alone was insufficient to fight Li Zicheng's main army.
[58] Central policy alone did not decide whether the walls would be built, as various "defense commands" (邊鎮, biānzhèn) along the border possessed considerable autonomy to deal with the nomads, leading to a decentralized approach to wall-building along the frontier.
[60] In essence, the Ming Great Wall was built in a piecemeal fashion by a number of regional commanders over a long period of time, not as one monumental project ordered by the central government.
[66] The Mongol Northern Yuan dynasty used to send ahead a force of up to a thousand men that carried pickaxes to break down the wall whose core consisted mostly of rammed earth.
Historians such as Arthur Waldron and Julia Lovell are critical of the whole wall-building exercise in light of its ultimate failure in protecting China; the former compared the Great Wall with the failed Maginot Line of the French in World War II.
