The Japanese sword (nihonto) has been internationally known for its sharpness and beauty since feudal times. The sword used to be the distinguishing mark of the samurai.
The sword was considered the soul of the samurai. Although other weapons waxed and waned in popularity throughout history, the sword remained a constant. Although spears have survived since as far back as the 8th century AD, it was not until the large scale wars of the Onin period towards the end of the fifteenth century that the straight bladed spear, the yari, vied with the sword for the most popular weapon. The Japanese pinned an extraordinary amount of value on the sword. For much of Japan's history, only samurai were even allowed to carry swords, and a peasant carrying a sword was enough reason to kill the peasant and take the sword after a prohibition was issued in early Edo period. Ronin, needing money, would sometimes be forced to sell their swords, further adding to their highly dishonorable, sometimes vagabond status in Japanese society. They would be "soulless" in the eyes of a samurai.
Much of early Japanese culture revolved around swords. Elaborate methods for carrying, cleaning, storing, sharpening (or not sharpening), and wielding the sword evolved from era to era.
For example, a samurai entering someone's house might consider how to place his sheathed sword as he knelt. Positioning his sword for an easy draw implied suspicion or aggression; thus, whether he placed it on his right or left side, and whether the blade was placed curving away or towards him, was an important point of etiquette. As for the host, his long-sword was generally stored above the wakizashi on a rack called a katana-kake, curving upwards; in the manner it was worn, with the omote side showing (tsuka or handle pointing left). The Tachi on the other hand, had a stand, the tsuka was set in a groove at the base and the saya pointed upwards set in a notch at the top with the cutting edge down, again in the manner it was worn.
However, until the Edo period most samurai did not use their sword as a primary weapon; they used a bow first, a spear next, and then the sword. Drawing the sword was like letting the soul blaze free when down to the last straw. To have fought until nothing but a surrender is possible was described as Ken ore, ya mo tsuki, (lit. "with swords broken and without an arrow") used as a proverb.
Katana (刀) is the Japanese backsword or longsword (大刀 daitō) of the type specifically in use after the 1400s (following the use of the tachi), although in Japanese this word serves generically as a catch-all word for sword. Katana (pronounced [kah-tah-nah]) is the kun'yomi (Japanese reading) of the kanji 刀 ; the on'yomi (Chinese reading) is tō. While the word has no separate plural form in Japanese, it has been adopted as a loan word by the English language, where it is commonly pluralised as katanas.