Mingrui

Mingrui (Chinese: 明瑞, Burmese pronunciation: [mɪ́ɴ jwì]; d. March 1768) was governor-general of Yunnan and Guizhou from April 1767 to March 1768. He was a nephew of Fuheng, the chief grand councilor to the emperor. Mingrui had seen battle against the Turks in the northwest and was in command of the strategically key post of Ili (in present-day Kazakhstan). A son-in-law of the Qianlong Emperor of China, Mingrui was appointed in 1767 by the emperor to lead a 50,000-strong invasion force led by the elite Manchu Bannermen in the third campaign of the Qing invasions of Burma. As a precaution against illness, the campaign was planned for the winter months when diseases were believed to be less prevalent.
The Burmese now had the largest Chinese army yet mobilized against them. Yet King Hsinbyushin did not seem to realize the gravity of the situation. Throughout the first two invasions, he had steadfastly refused to recall the main Burmese armies, which had been battling in Laos and Siam since January 1765, and laying siege to the Siamese capital of Ayutthaya since January 1766. Throughout 1767, when the Chinese were mobilizing for their most serious invasion yet, the Burmese were still focused on defeating the Siamese. Even after the Siamese capital was finally captured in April 1767, Hsinbyushin kept part of the troops in Siam during the rainy season months in order to mop up the remaining Siamese resistance during the winter months later that year. He actually allowed many Shan and Laotian battalions to demobilize at the start of the rainy season.
As a result, when the invasion did come in November 1767, the Burmese defenses had not been upgraded to meet a much larger and a more determined foe. The Burmese command looked much like that of the second invasion. Hsinbyushin again assigned the same commanders of the second invasion to face off the Chinese. 
Maha Sithu led the main Burmese army, and was the overall commander of the Chinese theater, with Maha Thiha Thura and Ne Myo Sithu commanding two other Burmese armies. Balamindin again commanded the Kaungton fort. Given that the main Burmese army was only about 7000 strong, the entire Burmese defense at the start of the third invasion was most likely no more than 20,000.
Mingrui planned a two-pronged invasion as soon as the rainy season ended. The main Chinese army, led by Mingrui himself, was to approach Ava through Hsenwi, Lashio and Hsipaw, and down the Namtu river. The main invasion route was the same route followed by the Manchu forces a century earlier, chasing the Yongli Emperor of the Southern Ming Dynasty. 
The second army, led by General E'erdeng'e, was to try the Bhamo route. The ultimate objective was for both armies to clamp themselves in a pincer action on the Burmese capital of Ava. The Burmese plan was to hold the second Chinese army in the north at Kaungton with the army led by Ne Myo Sithu, and meet the main Chinese army in the northeast with two armies led by Maha Sithu and Maha Thiha Thura.
At first, everything went according to plan for the Qing. The invasion began in November 1767 as the smaller Chinese army attacked and occupied Bhamo. Within eight days, Mingrui's main army occupied the Shan states of Hsenwi and Hsipaw. Mingrui made Hsenwi a supply base, and assigned 5,000 troops to remain at Hsenwi and guard the rear. He then led a 15,000-strong army in the direction of Ava. In late December, at the Goteik Gorge (south of Hsipaw), the two main armies faced off and the first major battle of the invasion ensued. Outnumbered two-to-one, Maha Sithu's main Burmese army was thoroughly routed by Mingrui's Bannermen. Maha Thiha Thura too was repulsed at Hsenwi. The news of the disaster at Goteik reached Ava. Hsinbyushin finally realized the gravity of the situation, and urgently recalled Burmese armies from Siam.
Having smashed through the main Burmese army, Mingrui pressed on full steam ahead, overrunning one town after another, and reached Singu on the Irrawaddy, 30 miles north of Ava at the beginning of 1768. The only bright spot for the Burmese was that the northern invasion force, which was to come down the Irrawaddy to join up with Mingrui's main army, had been held off at Kaungton.
At Ava, Hsinbyushin famously did not panic at the prospect of a large Chinese army (about 30,000) at the doorstep. The court urged the king to flee but he scornfully refused, saying he and his brother princes, sons of Alaungpaya, would fight the Chinese alone if they had to. Instead of defending the capital, Hsinbyushin calmly sent an army to take up position outside Singu, personally leading his men toward the front line.
It turned out that Mingrui had overstretched himself, and was in no position to proceed any farther. He was now too far away from his main supply base at Hsenwi, hundreds of miles away in the northern Shan Hills. The Burmese guerrilla attacks on the long supply lines across the jungles of the Shan Hills were seriously hampering the Qing army's ability to proceed. (Burmese guerrilla operations were directed by General Teingya Minkhaung, a deputy of Maha Thiha Thura). Mingrui now resorted to defensive tactics, playing for time to enable the northern army to come to his relief. But it was not to be. The northern army had suffered heavy casualties in their repeated attacks against the Kaungton fort. Its commander, against the express orders of Mingrui, retreated back to Yunnan. (The commander was later publicly shamed and executed on the orders of the Emperor.)
The situation turned worse for Mingrui. By early 1768, battle-hardened Burmese reinforcements from Siam had begun to arrive back. Bolstered by the reinforcements, two Burmese armies led by Maha Thiha Thura and Ne Myo Sithu succeeded in retaking Hsenwi. The Qing commander at Hsenwi committed suicide. The main Qing army was now cut off from all supplies. It was now March 1768. Thousands of Bannermen, nomadic tribesmen from the freezing grasslands along the Russian border, began dying of malaria as well as Burmese attacks in the hot weather of central Burma. Mingrui gave up all hope of proceeding toward Ava, and instead tried to make it back to Yunnan with as many of his soldiers as possible.
In March 1768, Mingrui began his retreat, pursued by a Burmese army of 10,000 men and 2,000 cavalry. The Burmese then tried to encircle the Chinese by splitting the army into two. Maha Thiha Thura had now assumed the overall command, replacing Maha Sithu. The smaller army, led by Maha Sithu, continued to pursue Mingrui while the larger army led by Maha Thiha Thura advanced through the mountainous route to emerge directly behind the Chinese. Through careful maneuvering, the Burmese managed to achieve complete encirclement of the Chinese at modern-day Pyinoolwin (Maymyo), about 50 miles northeast of Ava. Over the course of three days of bloody fighting, the Qing army was completely annihilated. The slaughter was such that the Burmese could hardly grip their swords as the hilts were slippery with enemy blood.
Of the original 30,000 men of the main army, only 2,500 remained alive and were captured. The rest had been killed either on the battlefield, through disease or through execution after their surrender. Mingrui himself was severely wounded in battle. Only a small group managed to break through and escaped the carnage. Mingrui himself could have escaped with that group. Instead, he cut off his pigtail and sent it to the emperor as a token of his loyalty by those who were escaping. He then hanged himself on a tree. In the end, only a few dozen of the main army returned.