Gunpowder and the gun were invented in China. And while knowledge of the former may have come about accidentally, the latter was unequivocally a weapon of war. The gun was created to kill people through an intentional exploitation of the properties of gunpowder. Of course, the gun was not the first or only weapon the Chinese invented to employ gunpowder for violent and destructive ends. A broad range of rockets, flamethrowers, grenades, smoke bombs, poison gas bombs, mines, and incendiary devices were also produced, demonstrating the ample resources in human ingenuity and materials expended in the interests of war. There was steady progress in the development of gunpowder weapons, with many new devices quickly applied on the battlefield. While in the eleventh century the Song dynasty had an established gunpowder-manufacturing bureau, and gunpowder weapons were included in a government-produced military manual, by the twelfth and thirteenth centuries gunpowder weapons were standard devices in sieges, battles, and naval combat. The true gun itself appeared in the mid-thirteenth century.

To the extent that gunpowder weapons played prominent, if not often decisive, roles in many twelfth- and thirteenth-century battles, there was a revolution in warfare even before the invention of the gun. The Complete Essentials from the Military Classics (Wujing Zongyao), finished in 1044, which currently ranks as the first text directly to describe the formula for gunpowder, was not, however, a pamphlet on new military devices and techniques; it was a compendium of all military knowledge up to that time.