China invented more military technology, over a longer period, than any other society in human history. Bronze metallurgy applied to weapons at industrial scale. The crossbow with interchangeable parts. The trebuchet. The repeating crossbow. Gunpowder. The rocket. The hand cannon. Almost every category of pre-industrial weapon either originated in China or was perfected there before being transmitted west along the Silk Road.
The Bronze Age and the dagger-axe
The earliest large-scale Chinese military history begins with the Shang dynasty in the second millennium BC. Shang armies were chariot-based, with bronze weapons cast in state-run workshops. The signature weapon of the period was the ge, the dagger-axe — a hooking, slashing blade mounted perpendicular to a long shaft, designed for use from a moving chariot against tightly-packed infantry. Tens of thousands of ge have been recovered from Shang and Western Zhou archaeological sites, in standardized dimensions that imply centralized production at an unprecedented scale for the era.
The Warring States and the crossbow
By the time the Zhou order collapsed into the Warring States period (roughly the 5th to 3rd centuries BC), Chinese warfare had become an arms race among rival states. Cavalry replaced chariots. Iron weapons replaced bronze. Mass infantry armies of conscripted peasants replaced aristocratic warrior elites. The most important innovation of the period was the crossbow — a weapon that allowed a moderately-trained conscript to outshoot a professional archer, and that gave decisive advantages to whichever state could produce it in the largest numbers. The state of Qin won the wars that ended this era, and unified China in 221 BC, in part because it could field crossbows by the hundreds of thousands.
The Han imperial system
The Han dynasty (206 BC – 220 AD) inherited the Qin military system and refined it into the standard form of Chinese imperial armies for the next millennium. State arsenals produced standardized weapons with interchangeable parts — particularly the crossbow trigger, whose surviving examples remain interchangeable across centuries and provinces. Han military doctrine emphasized combined arms: massed crossbows at distance, halberd-armed infantry at the front, swords for close combat, cavalry for envelopment and pursuit. The Han army that pushed back the Xiongnu and opened the Silk Road was, for its era, the most logistically sophisticated military organization in the world.
Gunpowder and the end of an era
Gunpowder was discovered in China in the 9th century by Daoist alchemists, and put into military use over the following centuries through a series of inventions that have no parallels anywhere else in the world: the first incendiary arrows, the first rockets, the first explosive bombs, the first hand cannons. By the late Yuan dynasty in the 13th century, China was producing the world's first true firearms. The full transition to gunpowder armies would take another four centuries, and by the time the Qing dynasty fell to European-armed Republican forces in 1912, China had been technologically overtaken by the West. But the foundational work — the demonstration that gunpowder could be turned into deliverable battlefield weapons — was Chinese.