The Korean army was therefore very primitive by Japanese standards, and this was further reflected in its equipment. The basic design of a suit of Korean armour consisted of a three-quarter-length heavy coat worn over an inner garment that resembled a divided apron, with trousers and leather boots. By the Koryŏ Period lamellar armour had been introduced, the lamellae being added either to the outside of the coat or inside it, or stitched inside the lining. The final version was the studded coat, whereby the heads of rivets, which held in place small plates inside the armour, protruded from its outside surface to give an appearance very similar to brigandine. Officers would also sport a bright coloured sash or belt over coats of red or blue, but the usual appearance for most wearers was of dull brown fabric of cotton or hemp.
The Korean helmet consisted of a simple rounded conical bowl made from four main pieces riveted together and secured round the brow. A neck guard of lamellae or brigandine was suspended from it in three sections, and decoration in the form of feathers could be flown from the helmet point. Officers' helmets could be lacquered black and ornamented with gold and fur. Korean foot soldiers wore no armour at all, just their traditional white clothes with a sleeveless black jacket and a belt, but a felt hat gave some small protection in battle.
Many Korean swords were two-edged, straight-bladed weapons, although curved swords like Japanese katana were also made, and actual Japanese models were imported. By contrast, Korean polearms showed considerable Chinese influence. Their use was most prized from the back of a horse, so we see cavalrymen armed with tridents, long straight spears and glaives with heavy curved blades much wider than a Japanese naginata. Unique to Korea, however, was the flail, a rounded hardwood stick, painted red and four feet long, to which was attached a shorter and heavier mace-like shaft studded with iron nails or knobs. The attachment was provided by a short length of chain. The flail was highly regarded, and successful candidates for the military examinations had to gallop along a trench and knock over a certain number of artificial heads. Foot soldiers were armed with all the above varieties of polearm except the flail.
Prowess at archery was also greatly valued, and the celebrated Admiral Yi Sun-sin was an accomplished archer. The ordinary Korean bow was a composite reflex bow, made from mulberry wood, bamboo, water buffalo horn and cow sinew spliced together. It had a pronounced negative curve, against which the bow had to be pulled in order to string it. A Japanese source from the time of the 1592 invasion claims that Korean bows were the one thing in which the Koreans were superior to the Japanese, because their range was 500 yards against the Japanese longbow's range of 350 yards.
The one thing the Korean army could be really proud of was its artillery. In addition to the cannon that were mounted on Korean warships or on the walls of castles, an army in the field could boast multiple rocket launchers firing volleys of steel-tipped arrows or darts, which were devastating against close formation troops if timed correctly. Otherwise it lacked armoured infantry, long spears and arquebuses, as well as proper organisation, combat experience, trained officers and a clear chain of command, and this was an army that was to face an invasion by one of the contemporary world's most sophisticated military machines.