A sword is a cold weapon with a long blade that is used to inflict stab and cutting wounds. Swords are the largest category of cold weapons; they can vary greatly in appearance depending on time period in history, conditions, and region of usage. Some weapons can not be easily identified as either swords or daggers because of their size so this division is sometimes debatable. Early swords were made of bronze, and the first swords made of steel date to the 14th century.
In Europe, swords tended to be straight with blades up to 90 cm (35") long, double or single-edged. In the East, India, and Africa, curved blades were much more popular. Early swords were single-handed swords weighing about 1.5 kg (3.4lb), and one and a half-handed and double-handed swords appeared only at the beginning of the 14th century. The center of gravity of a straight sword is usually near the guard to improve usability and to increase inertia, which is crucial in close combat. Straight swords differed by handle and blade length, shape of guard, and center of gravity, which tended to be situated as low as possible.
Despite popular myth, swords in the Middle Ages were very rare because of their high cost. The rarest ones were Damascus steel blades, which came to Europe only in 13th century and were available just for a small group of nobility. In the 14th century, the development of welding technology allowed the production of long swords available for an average warrior. Up to the beginning of the 15th century, one and half-handed swords were widely used; their weight was about 2.5-3 kg (5.5-6.6lb) and blade length ranged from 90 to 120 cm (35" to 47"). Double-handed swords with a blade length from 120 to 160 cm (47" to 63") were used primarily against cavalry or single fighters. Otherwise, because of its heavy weight, the double-handed sword was a weapon of only one strike, very uncomfortable for a long battle. The major benefit of a double-handed sword was its ability to pierce armor, which was impossible to achieve with other types of swords.
Unlike straight swords, the curved ones were all very different in blade length, shape of the whole piece, and their purpose. For example, in Africa small broadswords were widely used with blade length about 50 cm (20") and weight about 1.5kg. In Asia, Damascus blades were popular, and curved swords with divergent blades soon fell out of use and were replaced by sabers. In China, dao swords could weigh 3.5 kg and have blades up to 80 cm (32") in length, but Damascus blades were very popular because they were light (less than 1 kg) and short (50 cm or 25"). One of the most famous types of curved swords is a Japanese samurai sword katana – distinguished by its light weight and perfect cutting features.