Under the Ming dynasty, being a soldier was an inherited condition. This meant that the Ming army was recruited from a professional warrior class, however, quite unlike indo-european societies where the warrior class typically held high status (and often political power), the Ming-era Chinese considered their soldiers to be scum. This had a strong negative impact on the motivation and morale of their troops. The system's main advantage was that it allowed easy replacement of casualties--if a soldier was killed, his family had to furnish a replacement or lose their livelyhood and end up as beggars...
The Ming cavalry was exclusively light, being composed of horse archers and lancers (with shield, IIRC); early on it appears to have been very effective, but later on it declined sharply. The early Ming had to fight off the Yuan and their cavalry was largely built around the need to counter steppe nomads, and later the Yongle emperor is quote as saying that horses were the most important thing to a nation's military power. But after Yongle, both the Mongol influences and the Chinese imports of quality horses waned. Under the late Ming monarchs, "cavalry" was often actually mounted infantry. Although the cavalry caried sabres, these were apparently seldom used; the horse-archers avoiding melee and the lancers relying on the shock of their charge, and retreating if it failed to break the enemy.
The Ming infantry was organised into "companies" of 112 men each. These units, like European lances, were essentially admnistrative units containing proportions of different specialist troops which would logically be grouped together on the battlefield. About 40% of the ming footsoldiers (in theory, of course) were spearmen/pikemen, forming the main battle-line and holding off the attacks of the enemy, especially the cavalry of the steppe nomads. About as many soldiers would be armed with some kind of ranged weapon--bow, crossbow, or fire-arm of some kind (however, after the Yongle emperor, firearms were deployed by seperate 'firearms battalions'), so the Ming armies could put out a considerable volume of fire (quite necessary when facing horse-archer-based foes, might I add). The remainder were sword-and-shield troops, ostensibly to attack and defeat enemy infantry. The foot-soldiers were armoured with various combinations of chain, brigandine, and lamellar.
One feature that has to be noted about the Ming military was its centralisation, often excessive given the limitations of the time. The Ming government often re-equiped and re-trained entire armies for a specific campaign (see for instance Yongle's intensive preparations for his invasion of Dai Viet); however, Ming troops often lacked part (or even all) of their regular default equipment. The hereditary military system also made it impossible to adjust the military's size to the empire's current needs rapidly (in theory, the number of soldiers ought always to be the same) so that during times of relative peace large segments of the army were employed in a non-military capacity--noteably to transport grain to Beijing after Yongle moved his capital back there. This was expedient and economical, but ruined the fighting ability of the units concerned and eventually that of the entire army.
The Ming employed a vast number of weird and wondrous firearms and siege weapons. Perhaps the most important fire-arm was the fire lance--essentially a spear packed in a disposable launch tube and fired from the shoulder, like a modern anti-tank weapon. It filled broadly the same role as the latter, being able to penetrate just about any armour, and, according to the claims of some contemporary Chinese sources, several soldiers in one go (take this with a barrow-load of salt, however). Fire arrows (rocket-propelled arrows), various types of gonnes (including repeating ones), hand grenades, large rocket-missiles and a miscelleany of light and very light cannons were also common. Grapeshot was known and often fired from light, tripod-mounted guns that could be carried around by a two-man team. It should be noted that the Ming usually made use of iron bullets. Compared to lead projectiles, this made for smaller holes in people but superior armour-piercing abilities. In addition to killing people, the firearms were also extremely scary, especially for the Sout-East Asian elephants that had long been the bane of Chinese armies.
