Gunpowder weapons in the Song dynasty included fire arrows, gunpowder lit flamethrowers, soft shell bombs, hard shell iron bombs, fire lances, and possibly early cannons known as "eruptors". The eruptors, such as the "multiple bullets magazine eruptors" (bǎi-zi lián zhū pào, 百子連珠炮), consisting of a tube of bronze or cast iron that was filled with about 100 lead balls,Needham, Volume 5, Part 7, 263-364. and the "flying-cloud thunderclap eruptor" (fēi yún pī-lì pào, 飛雲霹靂炮), were early cast-iron proto-cannons that did not include single shots that occluded the barrel (thus called "co-viative" weapons). The use of proto-cannon, and other gunpowder weapons, enabled the Song dynasty to ward off its generally militarily superior enemies—the Khitan led Liao, Tangut led Western Xia, and Jurchen led Jin—until its final collapse under the onslaught of the Mongol forces of Kublai Khan and his Yuan dynasty in the late 13th century.
History
Fire arrow
The first fire arrows (huǒyào 火藥) were arrows strapped with gunpowder incendiaries, but in 969 two Song generals, Yue Yifang and Feng Jisheng (馮繼升), invented a variant fire arrow which utilized gunpowder tubes as propellants. Afterwards fire arrows started transitioning to rocket propelled weapons rather than being fired from a bow. These fire arrows were shown to the emperor in 970 when the head of a weapons manufacturing bureau sent Feng Jisheng to demonstrate the gunpowder arrow design, for which he was heavily rewarded.
In 975, the state of Wuyue sent to the Song dynasty a unit of soldiers skilled in the handling of fire arrows. In the same year, the Song dynasty used fire arrows and incendiary bombs to destroy the fleet of Southern Tang.
In 994, the Liao dynasty attacked the Song and laid siege to Zitong with 100,000 troops. They were repelled with the aid of fire arrows. In 1000 a soldier by the name of Tang Fu (唐福) also demonstrated his own designs of gunpowder arrows, gunpowder pots (a proto-bomb which spews fire), and gunpowder caltrops, for which he was richly rewarded as well. The imperial court took great interest in the progress of gunpowder developments and actively encouraged as well as disseminated military technology. For example, in 1002 a local militia man named Shi Pu (石普) showed his own versions of fireballs and gunpowder arrows to imperial officials. They were so astounded that the emperor and court decreed that a team would be assembled to print the plans and instructions for the new designs to promulgate throughout the realm. The Song court's policy of rewarding military innovators was reported to have "brought about a great number of cases of people presenting technology and techniques" (器械法式) according to the official History of Song. Production of gunpowder and fire arrows heavily increased in the 11th century as the court centralized the production process, constructing large gunpowder production facilities, hiring artisans, carpenters, and tanners for the military production complex in the capital of Kaifeng. One surviving source circa 1023 lists all the artisans working in Kaifeng while another notes that in 1083 the imperial court sent 100,000 gunpowder arrows to one garrison and 250,000 to another. Evidence of gunpowder in the Liao dynasty and Western Xia is much sparser than in Song, but some evidence such as the Song decree of 1073 that all subjects were henceforth forbidden from trading sulfur and saltpeter across the Liao border, suggests that the Liao were aware of gunpowder developments to the south and coveted gunpowder ingredients of their own. A text written by Song Minqiu prior to his death in 1079 includes a gunpowder factory under the Arsenals Administration:
Flamethrower
The Chinese flamethrower, known as the Fierce-fire Oil Cabinet, was recorded to have been used in 976 AD when Song naval forces confronted the Southern Tang fleet on the Changjiang. Southern Tang forces attempted to use flamethrowers against the Song navy, but were accidentally consumed by their own fire when violent winds swept in their direction.
According to the Wujing Zongyao, gunpowder was used to ignite the flamethrower:
The flamethrower was a well known device by the 11th century when it was joked that Confucian scholars knew it better than the classics. Both gunpowder and the fierce fire oil were produced under the Arsenals Administration of the Song dynasty. In the early 12th century AD, Kang Yuzhi recorded his memories of military commanders testing out fierce oil fire on a small lakelet. They would spray it about on the opposite bank that represented the enemy camp. The flames would ignite into a sheet of flame, destroying the wooden fortifications, and even killing the water plants, fishes and turtles.In 1126 AD, Li Gang used flamethrowers in an attempt to prevent the Jurchens from crossing the Yellow River. Illustrations and descriptions of mobile flamethrowers on four-wheel push carts were documented in the Wujing Zongyao, written in 1044 AD (its illustration redrawn in 1601 as well).
Explosives
The Jurchen people of Manchuria united under Wanyan Aguda and established the Jin dynasty in 1115. Allying with the Song, they rose rapidly to the forefront of East Asian powers and defeated the Liao dynasty in a short span of time. Remnants of the Liao fled to the west and became known as the Qara Khitai, or Western Liao to the Chinese. In the east, the fragile Song-Jin alliance dissolved once the Jin saw how badly the Song army had performed against Liao forces. The Jin grew tired of waiting and captured all five of the Liao capitals themselves. They proceeded to make war on Song, initiating the Jin-Song Wars. This was the first time two major powers would have access to equally formidable gunpowder weapons.
Initially the Jin expected their campaign in the south to proceed smoothly given how poorly the Song had fared against the Liao. However they were met with stout resistance upon besieging Kaifeng in 1126 and faced the usual array of gunpowder arrows and fire bombs, but also a weapon called the "thunderclap bomb" (霹靂炮), which one witness wrote, "At night the thunderclap bombs were used, hitting the lines of the enemy well, and throwing them into great confusion. Many fled, screaming in fright." The thunderclap bomb was previously mentioned in the Wujing Zongyao, but this was the first recorded instance of its use. Its description in the text reads thus:
Jin troops withdrew with a ransom of Song silk and treasure but returned several months later with their own gunpowder bombs manufactured by captured Song artisans. According to historian Wang Zhaochun, the account of this battle provided the "earliest truly detailed descriptions of the use of gunpowder weapons in warfare." Records show that the Jin utilized gunpowder arrows and trebuchets to hurl gunpowder bombs while the Song responded with gunpowder arrows, fire bombs, thunderclap bombs, and a new addition called the "molten metal bomb" (金汁炮). As the Jin account describes, when they attacked the city's Xuanhua Gate, their "fire bombs fell like rain, and their arrows were so numerous as to be uncountable." The Jin captured Kaifeng despite the appearance of the molten metal bomb and secured another 20,000 fire arrows for their arsenal.
The Ming dynasty scholar Mao Yuanyi states in his Wubei Zhi, written in 1628:
The Song people used the turntable trebuchet, the single-pole trebuchet and the squatting-tiger trebuchet. They were all called 'fire trebuchets' because they were used to project fire-weapons like the (fire-)ball, (fire-)falcon, and (fire-)lance. They were the ancestors of the cannon.Needham, Volume 5, Part 7, 22.
The molten metal bomb appeared again in 1129 when Song general Li Yanxian (李彥仙) clashed with Jin forces while defending a strategic pass. The Jin assault lasted day and night without respite, using siege carts, fire carts, and sky bridges, but each assault was met with Song soldiers who "resisted at each occasion, and also used molten metal bombs. Wherever the gunpowder touched, everything would disintegrate without a trace." The molten metal bomb was likely an explosive that contained molten metal and gunpowder.
Fire lance The fire lance, as implied by the name, is essentially a long spear or pole affixed with a tube of gunpowder, and as it saw more usage, the tube's length became longer and pellets were added to the composition. The earliest confirmed employment of the fire lance in warfare was by Song dynasty forces against the Jin in 1132 during the siege of De'an (modern Anlu, Hubei Province).
The Jin attacked with wooden siege towers called "sky bridges": "As the sky bridges became stuck fast, more than ten feet from the walls and unable to get any closer, [the defenders] were ready. From below and above the defensive structures they emerged and attacked with fire lances, striking lances, and hooked sickles, each in turn. The people [i.e., the porters] at the base of the sky bridges were repulsed. Pulling their bamboo ropes, they [the porters] ended up drawing the sky bridge back in an anxious and urgent rush, going about fifty paces before stopping." The surviving porters then tried once again to wheel the sky bridges into place but Song soldiers emerged from the walls in force and made a direct attack on the sky bridge soldiers while defenders on the walls threw bricks and shot arrows in conjunction with trebuchets hurling bombs and rocks. The sky bridges were also set fire to with incendiary bundles of grass and firewood. Li Heng, the Jin commander, decided to lift the siege and Jin forces were driven back with severe casualties.
The siege of De'an marks an important transition and landmark in the history of gunpowder weapons as the fire medicine of the fire lances were described using a new word: "fire bomb medicine" (火炮藥), rather than simply "fire medicine." This could imply the use of a new more potent formula, or simply an acknowledgement of the specialized military application of gunpowder. Peter Lorge suggests that this "bomb powder" may have been corned, making it distinct from normal gunpowder. Evidence of gunpowder firecrackers also points to their appearance at roughly around the same time fire medicine was making its transition in the literary imagination. Fire lances continued to be used as anti-personnel weapons into the Ming dynasty, and were even attached to battle carts on one situation in 1163. Song commander Wei Sheng constructed several hundred of these carts known as "at-your-desire-war-carts" (如意戰車), which contained fire lances protruding from protective covering on the sides. They were used to defend mobile trebuchets that hurled fire bombs.
By the 1270s, Song cavalrymen were using fire lances as mounted weapons as evidenced by the account of a Song-Yuan battle in which two fire lance armed Song cavalrymen rushed a Chinese officer of Bayan of the Baarin.
Naval bombs Gunpowder technology also spread to naval warfare and in 1129 Song decreed that all warships were to be fitted with trebuchets for hurling gunpowder bombs. Older gunpowder weapons such as fire arrows were also utilized. In 1159 a Song fleet of 120 ships caught a Jin fleet at anchor near Shijiu Island (石臼島) off the shore of Shandong peninsula. The Song commander "ordered that gunpowder arrows be shot from all sides, and wherever they struck, flames and smoke rose up in swirls, setting fire to several hundred vessels." Song forces took another victory in 1161 when Song paddle boats ambushed a Jin transport fleet, launched thunderclap bombs, and drowned the Jin force in the Yangtze.