of stars in the night sky to the esoteric allure of rising lightning.
In one common way to create the hamon, Mr. Kawachi paints a clay slurry onto the blade, which acts as an insulator. The thickness of the clay dictates the rate at which the steel will cool and thus the extent to which it will harden. The clay is applied thickly at the back of the blade and thinly near the edge. The slurry is applied in such a way that the different thicknesses produce a pattern that will become the hamon. These patterns can be relatively straight (sūgūha), semicircular waves (gunome), elongated waves (nōtare), or made to look like clove buds (choōji), to name a few.
After quenching the blade, Mr. Kawachi removes the clay and examines the newly created hamon on the steel.
When the slurry has been applied, the blade is ready to be heated and quenched. Mr. Kawachi heats the blade very carefully. The color of the glowing steel indicates the temperature, so the quench-hardening is done after the smithy has been plunged into darkness. Different effects can be created depending on slight differences in temperature on different surfaces of the blade. One wrong move and the sword could come out of the process fatally damaged. So it is with a careful eye that the smith watches, awaiting the perfect opportunity to quench the blade by dunking it into a trough of water.
At the precise moment, Mr. Kawachi decisively thrusts the blade into water. With a quick hiss and bubble, the hardened edge is produced. The sword’s metamorphosis during this moment is astonishing. First, the edge steel cools, quickly bending the blade’s curvature against the edge—in the opposite direction that it should go. Then, as the back of the blade cools and contracts, the curvature actually reverses creating the edge-forward shape. As a result of this process, the blade, which was nearly straight, now has an elongated edge. The graceful and deadly curve of the distinctive nihōntō is born. Removing the clay slurry, the smith reveals a crude view of the steel. After this transformation the blade requires some final shaping.
Final Shaping
Mr. Kawachi removes the clay. Using files and low-grit stones, he exposes the steel underneath and begins shaping the sword. He continues his work, carefully adjusting the lines and overall geometry. As the steel’s surface becomes smoother, the hamon begins to appear—the first glimpse of the blade’s unique temperline. A hamon is similar to a fingerprint—no two are exactly alike. Once the sword-smith’s shaping is complete, he considers whether he wants to carve grooves, decorative bas-reliefs, or in this case a poem, into the blade.
If hi (grooves) or hōrimōnō (decorative carvings) are to be cut into the surface of the shinōgi-ji, the surface between the center ridgeline and the back edge, it is done at this stage, before sending it off to the polisher. According to Mr. Kawachi, “Hōrimōnō engravings were originally intended to serve as religious talismans.”3 On the other hand, grooves serve both practical and aesthetic functions. Here, we see Mr. Kawachi carving a distinctive inkan motif into one of his blades. Inkan are usually stone seals, stamped in red, which serve as someone’s signature. Grooves, on the other hand, are highly functional. Coming in several varieties, grooves lighten the blade, making it easier to wield, while simultaneously maintaining structural rigidity. Although this might seem counterintuitive at first, blades with grooves remain strong in the same way that an I-beam does.
The smith waits before signing the blade to see if the finished product will meet his personal expectations. Much of the sword’s finishing work is yet to be done. Only a basic view of the hamon can be seen at this point. In this rough condition, the smith delivers the blade to the polisher for further refinement.
The Polishing Process
A professional, certified mūkansa-level tōgishi like Mr. Abe is a craftsman of the highest order. The tōgishi’s time is incredibly valuable. The polisher must use his expertise to determine the proper course of action for any given blade. Polishing a newly made sword can take nearly two weeks. The waiting list for a mūkansa-level tōgishi like Mr. Abe can be years long.
The stones themselves also warrant appreciation. Stones used in polishing swords are extremely expensive. In ancient times, they were prized gifts offered among feudal lords. Top polishers like Mr. Abe spend untold fortunes on innumerable stones. Each stone will interact with steel differently. Each sword will require a slightly different stone to highlight its beauty. Therefore, most sword polishers have large collections of stones.
The process of polishing a nihōntō is extremely demanding in time, knowledge, and physical skill. Mr. Abe has allowed me to incorporate material from our interviews, his writing, and his collaboration with Paul Martin for the purpose of accurately illuminating the polishing process.
Polishing a sword can be broken down into two main processes. The first process, foundation polishing (shita-ji-tōgi), involves refining the shape of the sword by rubbing it over a series of stones. The second, finish polishing (shiage-tōgi) is performed by moving finger-stones over the blade’s surface. Each of these processes can be broken down into several sub-tasks, each of which requires a particular stone. The steps, stones, and intended outcomes are summarized below.
Carving hōrimōnō into a blade requires great skill and a steady hand.
An example of a polishing workstation.
Wafer-thin pieces of narutaki are ready to be sliced into tiny pieces and assembled on thumb-tip for fine polishing.
A small sampling of polishing stones.
Foundation polishing consists of three main goals: a. Shaping the blade, b. Refining the shape, and finally c. Preparing the surfaces for finish polishing. It is during this process that the sword’s edge becomes sharp. Foundation polishing uses stones of a rough grit and therefore, must be done carefully so as not to ruin the geometry of the sword. The goals of foundation polishing, while avoiding the removal of too much steel, are to make the surfaces of the blade even, keep the ridge-lines formed correctly, and maintain the sword’s visual balance. This process also sharpens the edge of the blade. See the photo sequence on page 40.
The stones used for shaping the blade are the kōngō-dō and binsui-dō. Binsui-dō is used more frequently. With each changing stone, the sword is worked in varying directions, slowly and with great care. Too much pressure, or removing too much material could result in damaging the blade badly. The shaping of the blade is complete when the surfaces have been polished and the lines of the blade are geometrically correct.
The stones used for refining the blade’s surfaces are called kaisei, chō-nagura, and kōma-nagura. In refining the surface, all marks made during previous stages must be removed completely. To assist this, Mr. Abe marks two spots on the surface of the blade using ground deer antler and uses them as visual markers to guide his polish-strokes. Working the blade in alternating directions, this process slowly reveals the first glimpses of the hamon. With the surfaces refined, the polisher can move to the next step, using the ūchigūmōri stones.
The purpose of the ūchigūmōri stones is to start bringing out the blade’s artistic qualities. From
