The katana, or samurai sword as it is commonly labelled in contemporary terms, is instantly recognisable with its smooth razor-edged curved blade and its black handle with those characteristic white diamond-shaped grips.

The age of the sword could possibly be seen as the Edo period between 1603 and 1867 when there was comparative peace under the Tokugawa shoguns. The disarmament of all those who posed a threat to the bakufu began with Toyotomi Hideyoshi's 'Sword Hunt' of 1588 and the stage was set for the reunification of Japan, but one which Hideyoshi would not complete himself. Under the Tokugawa shoguns the erstwhile battle weapon of the samurai, the spear, was no longer needed so he reverted to the sword. This instrument thus became his display of rank because only the samurai were permitted to carry the sword or indeed any kind of weapon in Tokugawa Japan. 

The length of the blade was usually around 70cm and was classed as a long sword or daito. The interesting fact about the katana is that it is so-called because it was worn with the blade facing upwards and through the sash or belt on the left side, but when it was facing down with the scabbard suspended from the belt it was known instead as a tachi. A katana (or tachi) worn with the wakizashi or short sword, which was slung through the girdle across the stomach, was known as a daisho. When travelling a samurai of high rank might carry his daisho in a special case made of two pieces of lacquered wood complete with hinges and lock called a katana-zutsu and usually bore the owner's mon or badge.

Ancient Japanese swords were not curved but straight and cast in a single piece from handle to point. By the 11th century the katana gained its famous curved edge but it is doubtful that at this stage it had achieved anywhere near its formidable reputation for cutting, as in this period the samurai were first and foremost horse archers rather than swordsmen. Swordsmiths began to perfect their art in the 12th and 13th centuries and swords forged during this time and before 1596 are classed as old or koto, whereas those forged later are known as new or shinto. The forging of swords was so highly regarded that even an emperor, Gotoba (1184-1198), learnt the art.

The forging of blades was a long and complex art and the skills were transmitted from father to son which in turn made a sword synonymous with a particular family. Each family closely guarded its secrets of sword-making and oaths were sworn by the smiths to further cement this secrecy. Each smith had his own method of forging and his own method of blending iron and steel as well as for testing the materials. The blade was made from welding a strip of steel to a rod of iron upon which other strips were welded into the desire shape and length before the blade was split lengthwise, then folded and welded again many times - probably around thirty. A blade could be composed of pure steel while others were also of iron. Next, the process of tempering would begin with a clay-based compound applied thinly to the cutting edge and then to the rest of the sword. The wave pattern on the cutting edge depends on the way in which the mixture is applied. Once this is done the process of sharpening and polishing can begin. This was done by a special knife before being ground on a special stone over a period of quite a long time, possibly fifty days. Afterwards the blade was polished on an oiled stone and a final rubbing with composed flakes after which the smith engraved his mark or signature on the tang. Next, the smith then burnished it with a polishing needle, usually in the winter because new blades were susceptible to rust in the summer. Sometimes there were several craftsmen involved in the forging of a sword: a smith to forge the desire shape, a smith to fold the metal, a temperer, and even a specialist polisher. 

The making of a sword was something of a religious ceremony and according to Gilbertson the smith 'clad himself in his ceremonial dress and wore the yeboshi or small lacquered hat, while a shimenawa or straw rope was stretched across the smithy, with gohei suspended from it, to scare away evil spirits and invite the presence of good ones'.

It was said that a sword could contain the personality of the smith who forged it. For example, the smith Senzo Muramasa was an unbalanced, violent and psychotic individual and although he forged blades to a very high standard they were said to have embodied his madness and were said to hunger for blood and compel the wielder to commit acts of murder or suicide. The great Tokugawa Ieyasu was apparently accidentally wounded twice by such a blade and on one occasion when he examined a sword used to slice through a samurai's helmet at the pivotal battle of Sekigahara (1600) he cut himself on it and observed that it must be a Muramasa blade, as it indeed was. Other blades were said to bring luck (or misfortune), happiness or longevity.

Forgery of masters' blades was always a danger and the authorities created experts (called mekiki) with a keen eye to identify the genuine articles. It was a very important job because a good blade was worth a considerable sum. From the 12th century the mekiki signed a certificate or ori kami which stated the name and residence of the maker of the blade, its length and mentioned any idiosyncrasy by which it could be identified, and then stating how much it was worth in gold. The certificate was sometimes signed by more than one mekiki with seals impressed on the other side of the paper. Sometimes it was only possible to identify a particular blade when it was shined in the light in order for the details to become visible.

Further Reading

The Martial Arts - Michel Random.

Secrets of the Samurai - Oscar Ratti and Adele Westbrook.