Sacred arts: How to make a Japanese Samurai sword
12 June 2017
On the island of Kyushu in Japan, one of the country's last remaining families of Samurai sword makers are continuing an ancient tradition. Handmade in Japan follows the intricate stages as the Koyima family lovingly craft a sword, a process that takes many months.
Swords: A family tradition
The Samurai had their own code of behaviour, called bushido, and the sword was at its heart. For the Samurai it was a spiritual object imbued with enduring symbolic power.
When we make swords, there is a sense of sacredness we want to instill in them.Shiro Kunimitsu
Shiro Kunimitsu is an honorific name bestowed on the current head swordsmith of the Komiya family, which is one of the last families to use the traditional sword making techniques that have been passed down through generations.
Follow the process as the family work together to craft one of these exquisite swords. It takes months to complete, from hammering a block of molten steel to painstakingly bringing out the blade's beautiful tempered pattern called hamon.
1. The Raw Material: Tamahagane
The base material for the sword is tamahagane, which the family orders from a producer 100 miles away. Tamahagane means 'jewel steel', and is the result of high temperature heating of iron sand and charcoal in a tatara, or clay tub furnace.
In ancient times, steel scraps like nails or broken plows would often have been used.
2. Base forging the metal (shita-kitae)
If you're hammering for a long time, your hand can shake at lunchtime - you can't separate the chopsticksShiro Kunimitsu
Several members of the family are involved in this stage, which is hard physical work.
The temperature of the hearth is increased to heat the stacked tamahagane, which is hammered repeatedly to remove impurities.
Several different types of hammers are used on the anvil.
3. Folding and molding the metal (orikaeshi tanren)
The forged tamahagane is folded transversely and longitudinally many times. It is heated and then cooled by water at each stage, which oxidizes the steel surface. Removing these oxidized layers reduces the steel's impurities. The final shape of the metal is called a billet.
4. Creating the blade (hizukuri)
The shape of the blade is painstakingly formed using large and small hammers. The swordsmith works hard to sand down the edge of the blade in short sections.
Chisels are used in a shiage process to finalise the sugata or shape and outline of the sword.
5. Coating with clay (Tsuchi-oki and yakiba-tsuchi)
The sword is cleaned to eliminate oil or impurities on the surface. It is then coated with various layers of clay and stone mixture - the composition is one of the swordsmith's trade secrets. This coating becomes hardened during the following yakiire step. The precise thickness of the coating layers determines the cooling rate in quenching.
A hamon is the pattern that comes out once the tempering is done.
6. Hardening and quenching the blade (yakiire)
One of the vital stages in swordmaking is the yakiire or heating-quenching process.
In the past it was said that this is when the soul is infused into the sword.Shiro Kunimitsu
Smaller pieces of charcoal are used in the furnace, to protect the sword's clay coating. The unfinished steel sword is heated again in the furnace, at 720-800 degrees centigrade, and then plunged into a water box or mizubune.
Factors in play that determine success are the thickness and composition of the clay coating, the quenching temperature and cooling rate, and the sword's dimensions which determine its ability to endure tensile stress at the cutting edge.
The blade cools from the downward side up. It steadily warps, producing the classic curved shape. If everything isn't absolutely right at this stage, a crack in the steel could result.
The clay-painted areas don't temper, creating the hamon.
7. Final shaping and polishing (shitaji togi and shiage togi)
The smith inspects and adjusts the sword, making it perfectly straight and performing a basic togi or polish, before handing it over to the togishi.
Mitsutoshi Komiya spent 10 years learning how to polish samurai swords in Tokyo. Below he explains how he meticulously polishes for up to two months to complete the togishi's process.
8. Signing the sword (mei-kiri)
The smith uses a small chisel to sign his name on the blade, sometimes with variations depending on the quality or style of the sword.