Siege - Chinese and Mongols

Chinese and Mongols

In the Middle Ages, the Mongol Empire's campaign against China (then comprising the Western Xia Dynasty, Jin Dynasty, and Southern Song Dynasty) by Genghis Khan until Kublai Khan, who eventually established the Yuan Dynasty in 1271, with their armies was extremely effective, allowing the Mongols to sweep through large areas. Even if they could not enter some of the more well-fortified cities, they used innovative battle tactics to grab hold of the land and the people:

"By concentrating on the field armies, the strongholds had to wait. Of course, smaller fortresses, or ones easily surprised, were taken as they came along. This had two effects. First, it cut off the principal city from communicating with other cities where they might expect aid. Secondly, refugees from these smaller cities would flee to the last stronghold. The reports from these cities and the streaming hordes of refugees not only reduced the morale of the inhabitants and garrison of the principal city, it also strained their resources. Food and water reserves were taxed by the sudden influx of refugees. Soon, what was once a formidable undertaking became easy. The Mongols were then free to lay siege without interference of the field army as it had been destroyed... At the siege of Aleppo, Hulegu used twenty catapults against the Bab al-Iraq (Gate of Iraq) alone. In Jûzjânî, there are several episodes in which the Mongols constructed hundreds of siege machines in order to surpass the number which the defending city possessed. While Jûzjânî surely exaggerated, the improbably high numbers which he used for both the Mongols and the defenders do give one a sense of the large numbers of machines used at a single siege."

Another Mongol tactic was to use catapults to launch corpses of plague victims into besieged cities. The disease-carrying fleas from the bodies would then infest the city, and the plague would spread allowing the city to be easily captured, although this transmission mechanism was not known at the time. In 1346 the bodies of Mongol warriors of the Golden Horde who had died of plague were thrown over the walls of the besieged Crimean city of Kaffa (now Feodosiya). It has been speculated that this operation may have been responsible for the advent of the Black Death in Europe. The Black Death is estimated to have killed 30% – 60% of Europe's population.

On the first night while laying siege to a city, the leader of the Mongol forces would lead from a white tent: if the city surrendered, all would be spared. On the second day, he would use a red tent: if the city surrendered, the men would all be killed, but the rest would be spared. On the third day, he would use a black tent: no quarter would be given.

However, the Chinese were not completely defenceless, and from AD 1234 until 1279 the Southern Song Chinese held out against the enormous barrage of Mongol attacks. Much of this success in defense lay in the world's first use of gunpowder (i.e. with early flamethrowers, grenades, firearms, cannons, and land mines) to fight back against the Khitans, the Tanguts, the Jurchens, and then the Mongols.

The Chinese of the Song period also discovered the explosive potential of packing hollowed cannonball shells with gunpowder. Written later around 1350 in the Huo Long Jing, this manuscript of Jiao Yu recorded an earlier Song-era cast-iron cannon known as the 'flying-cloud thunderclap eruptor' (fei yun pi-li pao). The manuscript stated that (Wade-Giles spelling):

The shells (phao) are made of cast iron, as large as a bowl and shaped like a ball. Inside they contain half a pound of 'magic' gunpowder (shen huo). They are sent flying towards the enemy camp from an eruptor (mu phao); and when they get there a sound like a thunder-clap is heard, and flashes of light appear. If ten of these shells are fired successfully into the enemy camp, the whole place will be set ablaze...

During the Ming Dynasty (AD 1368–1644), the Chinese were very concerned with city planning in regards to gunpowder warfare. The site for constructing the walls and the thickness of the walls in Beijing's Forbidden City were favored by the Chinese Yongle Emperor (r. 1402–1424), because they were in pristine position to resist cannon volley and were built thick enough to withstand attacks from cannon fire.

For more see Technology of the Song Dynasty.