The parts of a katana: blade, tsuba and hardening line

A katana has two main parts: the blade and the mounting. The tip of the blade is called the kissaki, the edge ha, the back mune and the ridge along the side shinogi. The pale hardening line along the edge is called the hamon. The mounting consists of the blade collar habaki, the guard tsuba, the hilt tsuka with ornaments called menuki, the pommel kashira and the scabbard saya with the cord sageo. Beneath the hilt is hidden the tang, nakago, where the smith signed his name.

Facts

The blade from the top

The tip, the kissaki, is delimited by a transverse line called the yokote. It is the hardest part to forge and polish, and connoisseurs look there first. Along the side of the blade runs a ridge, the shinogi, and the surface between the ridge and the back is called the shinogi-ji. The edge, ha, is the hard cutting edge, while the back, mune, is tough and bends rather than breaks. The curve of the blade is called sori.

Between the edge and the ridge the hardening line, the hamon, can be seen as a white, misty band with a shape of its own: straight, wavy or shaped like cloves. It arises during hardening and is both technique and art. The line continues into the tip, where it is called the boshi. The diagram below shows the parts; point at them to see the names.

How the hamon arises

Japanese swords were forged from tamahagane, a steel produced from iron sand and charcoal in a clay furnace. The smith folded the steel many times to even out the carbon content and remove slag, and the folding gives a pattern in the surface called hada, like the grain of wood. Often a harder steel was set around a softer core.

Before hardening the blade was coated with clay, thin at the edge and thick on the back. When the glowing blade was cooled in water, the edge cooled quickly and became very hard, while the back cooled more slowly and remained tough. The difference also gives the blade part of its curve. The boundary between the two zones is the hamon. In it can be seen small glittering crystals, nie, and a softer haze, nioi, which connoisseurs assess like brushstrokes in a painting.

The mounting: from habaki to kashira

Closest to the blade sits the habaki, a collar of copper, silver or gold that locks the blade in the scabbard and absorbs the shock of a blow. Then comes the tsuba, the guard, which protects the hand. During the Edo period the tsuba became a craft art of its own, often of iron with openwork patterns or inlaid gold and silver, and today they are collected as small sculptures.

The hilt, tsuka, is of wood covered with ray skin and wound with silk braid in a diamond pattern that gives a firm grip. Beneath the binding sit the menuki, small metal ornaments of dragons, flowers or animals that fill the palm. At the far end sits the pommel, the kashira. The hilt is held to the tang by a small bamboo peg, the mekugi, so that the blade can be removed and examined. The whole mounting is called the koshirae.

The scabbard and the hidden part

The scabbard, saya, is of light magnolia wood and lacquered, in black or in colour. On the side is a small knob, the kurikata, where the cord sageo is attached to tie the scabbard to the belt. A sword that is stored without being used is often placed in a plain scabbard of natural wood, a shirasaya, so that the blade can breathe.

The most important part for a historian cannot be seen. The tang, nakago, sits inside the hilt and must never be polished. There is the smith's signature, mei, sometimes with the year and place, and the rust patina and file marks of the tang help to determine age and authenticity. Many of the most celebrated swords are nevertheless unsigned or have had their tangs shortened.

Masamune and the history of the sword

Curved Japanese swords emerged during the Heian period. The oldest, tachi, were worn slung with the edge downwards. During the Kamakura period, the era of the samurai, the art of swordsmithing reached its peak, and the smith Masamune, active in Sagami Province around 1300, is regarded as Japan's foremost. Fudō Masamune, a short sword with an engraving of the deity Fudō, is one of very few securely attributed to him; it belonged to the Tokugawa family and is today in Nagoya.

The katana in the narrow sense, worn through the belt with the edge upwards so that it could be drawn and strike in a single movement, became common during the Muromachi period. During the Edo period the samurai wore a pair, a long katana and a shorter sword, the wakizashi. After 1876 it was forbidden to wear swords in public, and swords became art objects; see modern Japan.

Looking at a Japanese sword

In a museum the blade often lies on its own, without its mounting, with the light directed so that the surface can be seen. Go close and follow the hamon from the hilt up to the tip. Is the line straight or wavy? Can you see small glittering points? Does it continue evenly into the kissaki? Then look at the hada, the pattern in the steel, and at how the curve is distributed along the blade.

The mountings are often shown in cases of their own, and there you can follow how tsuba and menuki became a miniature art of their own with subjects from the same world as the woodblock prints; read the guide to ukiyo-e. The swords belong to Japanese art history as much as the paintings do. Chinese porcelain has a corresponding vocabulary of its own; see Chinese vase shapes, and on temples and houses in Japanese architecture.

What to look for

Exercise

What is the pale hardening line along the edge of the blade called?