The ''Huolongjing'' provided info for various gunpowder compositions, including 'magic gunpowder', 'poison gunpowder', or 'blinding and burning gunpowder'. It had descriptions of the Chinese hollow cast iron grenade bomb, shrapnel bombs, and bombs with poisonious concoctions. The book had descriptions of the 10th century Chinese fire arrow, a simple wooden arrow with a spherical soft casing attached to the arrow and filled with gunpowder, ignited by a so that it was propelled forward . However, the book explained how this simple 'fire arrow' evolved into the metal-tube launched rocket. The book provided descriptions of various rocket launchers that launched tons of rockets at a time, the advent of the having a booster rocket igniting a swarm of smaller ones that were shot from the mouth of a missile shaped like a , and even fin–mounted winged rockets. The book described the use of explosive land mines and descriptions of explosive naval mines at sea and on the river; this incorporated the use of a complex trigger mechanism of falling weights, pins, and a steel wheellock to ignite the train of fuses. The book described various proto–guns including the fire lance , multiple metal barrel handguns , and descriptions of handguns with possible serpentine locks, used as components in matchlock firearms. The book provided descriptions of the early bombard and cannon, including the use of hollow gunpowder–packed s, cannon barrels filled with tons of metal balls containing poisonous gunpowder solutions, and cannons that were mounted on wheeled carriages so that they could be rotated in all directions.
Although Jiao Yu did not provide the book's preface until the Nanyang publication of 1412 AD, the book was previously published in the 14th century , and was a compilation of material written since the late 13th century. From his own personal accounts Jiao Yu also described gunpowder weapons that were used since 1355 AD, with his involvement in the Red Turban Rebellion and revolt against Yuan Dynasty Mongol rule.
By the 15th century, European innovations in firearms, cannons, and other gunpowder weapons began to surpass Chinese innovation that was made in the 14th century. This included the European gun and culverin, the wheellock musket, and then the flintlock musket of the mid 17th century. By the late 16th century, the Chinese adopted Western-style muskets while employing style firing positions.
Gunpowder warfare and weapons
Firearms and flamethrowers
The military treatise of Jiao Yu and Liu Ji went into a great amount of detail on the gunpowder weapons of their time. The fire lance and fire tube came in many different versions and were styled with many different names by the time Jiao Yu edited the ''Huolongjing''. The earliest of these were made of bamboo tubes, although the earliest transition to metal was made in the 12th century. Some of these low–nitrate gunpowder flamethrowers used poisonous mixtures, including arsenious oxide, and would blast a spray of porcelain bits as shrapnel. The earliest depiction of a fire lance is dated c. 950 AD, a Chinese painting on a silk banner found at the Buddhist site of Dunhuang. Furthermore, the oldest existent bronze handgun is from the Heilongjiang archeological excavation, dated to 1288 AD. For that year, the ''Yuan Shi'' historical text describes the rebellion of the Christian Mongol prince Nayan and the Jurchen-born military commander Li Ting who, along with a brigade conscripted by Kublai Khan, suppressed Nayan's rebellion by using foot soldiers armed with handguns and portable bombards. The earliest metal barrel guns were not designed for high–nitrate gunpowder and a bore–filling projectile; rather, they were designed for the low–nitrate flamethrower fire lance that shot small co–viative missiles. This was called the 'bandit–striking penetrating gun' , and was illustrated in a drawing of the ''Huolongjing''. In Europe the first representation of the fire lance is of a horse–mounted knight wielding the weapon in a Latin manuscript illustration dated to 1396, and also appeared in an of Taccola's ''De Mechinis'' . The ''Huolongjing'' also described and illustrated metal–barrel handguns as well, including guns with three barrels, five barrels, six barrels, and even up to ten barrels. Furthermore, it described the use of a 'match–holding lance gun' , possibly an early serpentine matchlock. Although a proper illustration for this one was not included, it described its arrangement as a match brought down to the touch hole of three gun barrels one after the other. During the reign of the Yongle Emperor , the Shenji Brigade was formed, with cavalry horses that were said to have tubes filled with flammable materials holstered to their sides, along with troops with firearms and light artillery on carriages.
In addition to firearms and fire lances, the Huolongjing also illustrated the tall vertical mobile shield to hide and protect infantry gunmen, known as the 'mysteriously moving –breaking fierce–flame sword–shield'. This large rectangular shield would have been mounted on wheels, with five rows of six circular holes each where the gun barrels could be placed, and the shield itself would have been accompanied by swordsmen on either side to protect the gunmen. although the oldest archeological discovery of a cannon is a bronze cannon of China inscribed with the date "2nd year of the Dade era, Yuan Dynasty" . The prototype to the metal barrel was of course one made of bamboo, which was recorded in use by a Chinese garrison commander at Anlu, Hubei province, in the year 1132. One of the earliest references to the destructive force of a cannon in China was made by Zhang Xian in 1341, with his verse known as ''The Iron Cannon Affair''. Zhang wrote that its cannonball could "pierce the heart or belly when it strikes a man or horse, and can even transfix several persons at once." He wrote that some cannons were simply filled with 100 or so lead balls, but others had large rounds that produced a bursting charge upon impact, called the 'flying–cloud thunderclap eruptor' . In perspective, exploding cannonball rounds were not discovered in Europe until the 16th century. Furthermore, he noted the use of the 'poison–fog magic smoke eruptor', where 'blinding gunpowder' and 'poisonous gunpowder' were packed into the hollow cannonball shells, and were effective in burning the faces and eyes of enemies, along with choking them with a formidable spray of poisonous smoke. He wrote that cannons were mounted on frames or on wheeled carriages, so that they could be rotated in all directions.
Land mines and naval mines
The first recorded use of a land mine stated that the officer Lou Qianxia of the late Song Dynasty created them in order to kill invading Mongol troops in 1277 AD. Jiao Yu wrote that land mines were spherical in shape, made of cast iron, and their fuses ignited by the enemy movement disturbing a trigger mechanism. Although his book did not elaborate on the trigger mechanism, a late Ming Dynasty book of 1606 AD revealed that a complex system of a pin release, dropping weights, and chords and axles worked to rotate a spinning 'steel wheel' that acted as a flint to provide sparks that ignited the mines' fuses underground. For the use of naval mines, he wrote of slowly burning joss sticks that were disguised and timed to explode against enemy ships floating nearby:
In the later ''Tiangong Kaiwu'' treatise, written by Song Yingxing in 1637 AD, the ox bladder described by Jiao Yu is replaced with a lacquer bag instead, along with a cord pulled from a hidden ambusher located on the nearby shore, which would release a flint steel–wheel firing mechanism to ignite the fuse of the naval mine.
Gunpowder and explosives
There were several gunpowder compositions proposed by Jiao Yu, with additions to the standard formula of saltpetre, sulphur, and charcoal by adapting gunpowder weapons to early chemical warfare. He described the suitable uses of 'magic gunpowder', 'poison gunpowder', or 'blinding and burning gunpowder' in warfare, which displays the various amounts of compositions used in his time. For the making of poisonous gunpowder in hand–lobbed or catapult–launched grenade bombs, For this, Jiao Yu wrote "even birds flying in the air cannot escape the effects of the explosion". It is important to note that during the 14th century, Chinese gunpowder solutions had reached their maximum explosive potential, with levels of nitrate ranging from 12% to 91% and at least 6 formulas in use by the Chinese that were considered to have maximum explosive force. This also came about due to the enrichment of sulfur from pyrite extracts during the earlier Song Dynasty period, while Chinese gunpowder formulas by the late 12th century and at least by 1230 AD were potential enough for explosive detonations and bursting cast iron shells. The root of all this was the Chinese military handbook written in 1044 AD, the ''Wujing Zongyao''; it outlined the earliest use of formulas for gunpowder, employed in bombs hurled by catapults. Later, Wei Xing of the Song Dynasty was said to have created a gunpowder formula of saltpetre, sulphur, and willow charcoal for his projectile carriages launching 'fire–stones' up to 400 yards.
Although its destructive force was widely recognized even by the 11th century, the Chinese had earlier termed gunpowder as a 'fire–drug' , due to Chinese beliefs in its pharmaceutical properties. Its valuable use in festival entertainment could be seen in fireworks displays, such as the martial demonstration in 1110 AD to entertain the court of , with dancers in strange costumes moving through clouds of colored smoke. After the ''Wujing Zongyao'' of 1044 had explicitly stated formulas for gunpowder, the Chinese government became frightened that its use could fall into the hands of surrounding enemies at the borders, and in 1076 enacted a strict governmental monopoly over the production and distribution of sulfur. Although saltpetre was a central component of the 'fire–drug' and a flavor enhancer for food during the Tang and Song periods, in 1067 the Song government banned the people of modern Shanxi and Hebei provinces to sell foreigners both sulfur and saltpetre in any form. While engaged in a war with the Mongols, in the year 1259 the official Li Zengbo wrote in his ''Ko Zhai Za Gao, Xu Gao Hou'' that the city of Qingzhou was manufacturing one to two thousand strong iron-cased bomb shells a month, dispatching to Xiangyang and Yingzhou about ten to twenty thousand such bombs at a time.
Fire arrows and rockets
For the earliest fire arrows launched from bows , Jiao Yu had termed these "fiery pomegranate shot from a bow". The term pomegranate stemmed from the fact that the lump of gunpowder–filled paper wrapped round the arrow just below the metal arrow–head resembled the shape of a pomegranate. He advised that a piece of hemp cloth should be used to strengthen the wad of paper, and then sealed fast with molten pine resin. An even earlier Chinese text of the ''Wujing Zongyao'' , written in 1044 AD by the Song scholars Zeng Gongliang and Yang Weide, described the use of three spring or triple bow that fired arrow bolts holding gunpowder. Even after the rocket was invented in China the fire arrow continued in use; this could be seen in the Second Opium War, where Chinese used fire arrows against the in 1860.
By the time of Jiao Yu, the term 'fire arrow' had taken on a whole new meaning and incorporated what were the earliest rockets found in China. the text reads: