Invention of Gunpowder in China: From Elixir to Weapon

The invention of gunpowder in China is one of the most consequential discoveries in history. By around the 9th century, during the Tang dynasty, Chinese alchemists searching for elixirs of immortality had found that mixtures of saltpetre, sulphur and carbon burned violently. Over the following four centuries the Song state turned this “fire medicine” into fire arrows, bombs and the fire lance, the ancestor of every gun.

Alchemy and “fire medicine”

Chinese alchemy, closely linked to Daoism, tried to create medicines that would extend life. Alchemists heated minerals and plant materials together, and by the Tang period they knew saltpetre (potassium nitrate), which they used in medicines and in “subduing” or purifying other substances by fire.

The Chinese word for gunpowder, huoyao, literally means “fire medicine”, a reminder of these origins. A Daoist text known as the Zhenyuan miaodao yaolüe, usually dated to the 9th century although its date is debated, warns that some practitioners had mixed sulphur, realgar, saltpetre and honey and suffered burned hands and faces, and even burned down the houses where they worked.

That warning is the earliest known description of a gunpowder-like mixture. It shows that the reaction was known and regarded as dangerous long before anyone wrote down a precise recipe.

How gunpowder works

Gunpowder is not a fuel that needs air. Saltpetre supplies oxygen as it decomposes, so the charcoal and sulphur mixed with it can burn extremely fast, even inside a closed container. Charcoal is the main fuel, while sulphur lowers the temperature at which the mixture ignites and speeds up the reaction.

The proportion of saltpetre decides what the mixture does. With little saltpetre it smoulders and flares, which suits incendiary arrows and smoke bombs. With more, and with ingredients ground finely and mixed thoroughly, it burns fast enough to build up gas pressure, which can burst an iron casing or drive a projectile down a barrel.

Producing reliable gunpowder was therefore as much a matter of chemistry and manufacturing as of invention. Natural saltpetre had to be collected from soils and purified by dissolving and recrystallising it, a skill that Chinese workshops mastered well before anyone else. Song military workshops in the capital employed specialist craftsmen for fire weapons alongside makers of crossbows and siege engines.

From laboratory to battlefield

The period after the fall of the Tang in 907 was one of constant warfare, and the new mixture quickly attracted military interest. A reference to “flying fire” at the siege of Yuzhang (modern Nanchang) in 904 is sometimes taken as an early gunpowder weapon, though historians disagree about whether it meant gunpowder or simply incendiary arrows.

Stronger evidence comes from art. A Buddhist silk banner from Dunhuang, dated to around the mid-10th century and now in Paris, shows demons attacking the Buddha; one holds a tube spurting flame that many scholars identify as a fire lance, and another holds what looks like a bomb. In the same era the southern kingdom of Wuyue used flamethrowers that sprayed petroleum, possibly ignited with a gunpowder fuse.

Under the Song dynasty, founded in 960, gunpowder weapons became part of the state arsenal. Song records note officers presenting fire arrows and fire balls to the court around 1000, and the government organised workshops to make them in quantity.

The Wujing Zongyao of 1044

The first surviving written formulas for gunpowder appear in the Wujing Zongyao (“Collection of the Most Important Military Techniques”), compiled by Zeng Gongliang, Ding Du and others and completed in 1044 under Emperor Renzong. It is one of the most important technical books of the medieval world.

The manual gives three recipes: one for an incendiary ball launched by catapult, one for a “thorny fire ball” studded with iron spikes and one for a “poison smoke ball”. Besides saltpetre, sulphur and charcoal they include ingredients such as resin, wax, oil and arsenic compounds.

These early mixtures contained relatively little saltpetre, roughly a third to a half in modern calculations, compared with about three-quarters in later gunpowder. As a result they burned fiercely and produced smoke but did not detonate. Early gunpowder was an incendiary, not yet an explosive.

The Song state treated the materials as strategic goods. In the later 11th century it restricted the trade in sulphur and saltpetre and banned their sale to foreigners, showing that the government understood their military value.

Bombs, fire lances and the wars of the 12th and 13th centuries

The long wars between the Song and the Jurchen Jin dynasty pushed gunpowder technology forward rapidly. During the siege of Kaifeng in 1126, the prelude to the Jingkang Incident, the defender Li Gang used “thunderclap bombs” against Jin troops.

In 1132 the Song commander Chen Gui defended the city of De’an with fire lances, the first clearly recorded use of the weapon in battle. These were bamboo tubes packed with gunpowder, attached to spears, which shot flames for a few minutes at close range.

At the Battle of Caishi in 1161 Song paddle-wheel warships hurled thunderclap bombs containing lime and sulphur at a Jin fleet on the Yangtze. Over time, saltpetre content rose, and by the early 13th century iron-cased bombs that truly exploded were in use.

The Jin used such bombs, called “thunder-crash bombs”, together with improved “flying fire lances”, against the Mongols during the Mongol siege of Kaifeng in 1232. Chinese sources describe the explosions as audible over great distances and able to pierce iron armour.

Meanwhile the fire lance gradually changed. Bamboo gave way to paper, then to metal barrels, and the projectiles grew from loose shrapnel to bullets that filled the bore. This is the key step from a flamethrower to a true gun.

The oldest surviving metal guns are Chinese and date from the late 13th century. The bronze Heilongjiang hand cannon, linked with fighting in 1288, and a bronze gun inscribed with a date corresponding to 1298 are usually cited as the earliest securely dated examples. Rockets, using the thrust of burning gunpowder, also appeared in China by the 13th century.

Key people

• Unnamed Daoist alchemists: the true discoverers of gunpowder, known only through warnings and recipes in their texts.
• Zeng Gongliang and Ding Du: senior Song officials who led the compilation of the Wujing Zongyao (1044).
• Li Gang: Song minister who organised the defence of Kaifeng in 1126 using gunpowder weapons.
• Chen Gui: Song official whose defence of De’an in 1132 records the first battlefield use of the fire lance.

Spread to the rest of the world

Gunpowder knowledge travelled west in the 13th century, most likely through the Mongol Empire, which employed Chinese engineers in its campaigns, and along Eurasian trade routes. In the Islamic world the Syrian writer Hasan al-Rammah set down detailed recipes for gunpowder and rockets around the 1270s to 1280s; Arabic writers of the period sometimes called saltpetre “Chinese snow”.

In East Asia the knowledge spread as well. In Goryeo Korea the official Choe Mu-seon learned how to refine saltpetre from a Chinese merchant, and in 1377 the government set up an office to manufacture gunpowder weapons, which were soon used against pirate fleets. In China itself, the Ming dynasty founded in 1368 equipped large numbers of troops with handguns and cannon, and the 14th-century manual known as the Huolongjing illustrated a wide range of gunpowder devices.

In Europe, the English friar Roger Bacon described firecrackers in works of the 1260s. Cannon appear in European illustrations by 1326 and were used in the Hundred Years’ War, probably including at the Battle of Crécy in 1346. In 1453 huge Ottoman bombards helped breach the walls of Constantinople.

Myths and facts

• Myth: the Chinese used gunpowder only for fireworks. In fact, Chinese states used it in war from at least the 10th century and developed bombs, fire lances and guns long before Europe.
• Myth: gunpowder was invented in a single moment. It developed gradually over centuries, from alchemical accident to incendiary to true explosive.
• Myth: a European monk invented gunpowder. Legends name the German monk Berthold Schwarz, but he is probably a fictional figure, and gunpowder was known in China centuries earlier.

By the numbers

Timeline

• 9th century: Daoist texts describe accidental fires from mixtures of saltpetre and sulphur.
• c. 950: A Dunhuang banner appears to show a fire lance and a bomb.
• c. 1000: Song officers present fire arrows and fire balls to the court.
• 1044: The Wujing Zongyao records the first known gunpowder formulas.
• 1126: Thunderclap bombs are used in the defence of Kaifeng.
• 1132: Chen Gui uses fire lances at the siege of De’an.
• 1161: Song ships throw gunpowder bombs at the Battle of Caishi.
• 1232: Jin forces use iron-cased bombs against the Mongols at Kaifeng.
• 1260s–1280s: Gunpowder recipes are recorded in Europe and the Islamic world.
• 1288: Approximate date of the Heilongjiang hand cannon.

Why it matters

Gunpowder began as a by-product of the search for immortality and ended by transforming warfare across the globe. Bombs, guns and cannon changed how cities were defended, how empires were built and eventually how states were organised, from Ming China to early modern Europe.