Battle of Tumu Fortress

Battle of Tumu Fortress (ch. 土木堡之變 tu3 mu4 bao3 zhi1 bian4) was frontier conflict between Mongolia and the Chinese Ming Dynasty leading to the capture of Zhengtong Emperor of China[?] on September 8, 1449 by an utterly wrong depolyment.

In August (the 7th month of the Chinese Lunar Calendar) Esen Tayisi (也先 ye3 xian1) of the Oyirad Mongols attacked the Chinese frontier with several thousand cavalries at Datong castle (today Datong County[?], Shanxi Province), located north and without protection of the Great Wall of China. Aided by Jurchen and diversionary attacks the Chinese staionary forces were annilihated. Zhengtong Emperor of China[?] favoured an eunuch Wang Zhen[?] at the time, who suggested the emperor to lead an ambitious expedition of five hundred thousands troops to boost morale.

Esen faked a complete withdrawal back to Mongolian steppes; the emperor and Wang Zhen ran right into an ambush by chasing the Mongolian to the west and arrived at Datong. In the night of September 3 (Chinese lunar calendar: 8th day of the 8th month), Esen wiped out all defense and sieged the Datong castle. The Chinese army managed to broke the siege and was chased as they retreated back to the Great Wall. Struck by an thunderstorm and hugh drop of morale, the Chinese army was caught on the north side of a barrack, the Tumu Fortress, in the morning of September 8 (Chinese lunar calendar: 13th day of the 8th month). Esen laid siege and overwhelmed its defense in late afternoon despite Wang Zhen led a final charge two hours before. The emperor was captured and mostly of his accompanying bureaucrats including Wang Zhen were killed among the confused soldiers.