Sword Polishing Techniques Unique to Japan
When swords are displayed in museums outside of Japan, they are probably hung on thewall crossed. When swords are displayed in Japan, they are in cases with special
lighting so that the viewer can see the hamon (differentially hardened edge) and thejigane (the folded outer steel of the blade). This is where swords of Japan differ from therest of the world. They are not just sharpened and burnished; they undergo a specialized
polishing process called kenma.
What is kenma?
The explanation of the forging process was quite long. However, the main points of thepolishing process can be explained in one article.
Other Japanese tools such as chisels, planes and kitchen knives are only sharpened on
the cutting edge. However, in contrast with other countries, not only the cutting edge of
the Japanese sword is ground. The whole blade apart from the handle is polished. This
is not to simply decorate the blade by making it shiny. All polishers try to create a ‘clear
polish’. It must be like clear water when the gravel at the bottom is clearly visible. This
pure and clear polish is the essence of kenma. This is because the sword was the weaponof the samurai, whilst at the same time associated with the gods of Japan. As it is anobject of the gods, so it must therefore be also a thing of beauty.
When the samurai emerged at the start of the 12th century in the Kamakura period,
polishing techniques and polishers had already appeared. When the Japanese sword as
we know it was evolving, it became the ‘soul of the samurai’. Unless you are aware ofthis concept, you will not be able to understand the importance of the sword in the mindof the Kamakura samurai going to fight in the Great East Asian Wars. The continuity ofthe sword right through Japanese history expresses this.
I would now like to explain the polishing process stage by stage. Polishing is broken
into two main stages: shitaji-togi (foundation polishing) and shiage-togi (finishpolishing). First I would like to explain the various tools and types of polishing stones
essential to the process. Maintaining the correct mental attitude whilst polishing is very
important. If this deteriorates then it is not kenma. Similar to martial arts, posture is very
important. Without using power, one must use the whole body to polish. The polisher
supports his weight on his knees and moves the blade from side to side. This also
restricts him from moving back and forth, which would ruin the polishing stroke. There
are no measuring tools used. The job of carefully forming the niku (the cross sectional
optimal form for efficient cutting: the meat of the blade) is a long and arduous one. Onlya small amount of pressure is put into the push stroke, and none in the pull stroke.
Shitaji-togi is the process for perfecting the basic shape of the blade. The tools are very
simple to look at. However, polishing requires a vast amount of knowledge that has
been accrued by generations of polishers. For instance, the stool used is called a shõgi.
Is not for actually sitting on. This is because there is a tool used called a fumaegi. The

correct posture is to put your right thigh onto the stool, whilst the rest of your bodyhangs in the air. There are tales of some apprentices putting an egg under their bottom,
to ensure that they do not put their weight onto the stool. It is said that the polisherresembles a bird perched on a branch. By using this posture the polisher is in complete
control and if he notices something is not quite right, he can stop immediately. Martial
artists will understands this as zanshin. Also, the way in which the tools are arranged isunique. They are positioned so that the polisher can work smoothly and continuously forextended periods comfortably.
The polisher uses 6 various grades of polishing stone from very coarse to very fine: iyodo, binsui-do, kaisei-do, nagura-do, koma-nagura-do and uchi-gumori-do. Every stone
has a slightly different purpose. At the same time as forming the shape, the activities inthe steel also begin to appear.
Uchi-gumori is the last stone used in foundation polishing. There are two types of thisstone: uchi-gumori hato, and uchi-gunori jito. Up to now the blade has been pushed
across the stone, in these stages it is now pulled. Lastly, the foundation work of thekissaki (point-section) is completed using uchi-gumori hato.
Next, is shiage-togi: finish polishing. During these stages, the beauty of the jigane andthe characteristics of the hamon are brought out. The processes in this section are:hazuya, jizuya, nugui, hadori and migaki. In these stages, not only the stones aredifferent, but also the way in which they are used. This is only a basic guide to theprocess, as the each of the various schools uses slightly different methods of polishing.
These special techniques have been passed down from long ago orally from teacher tostudent secret to each school. This process is so detailed that it cannot be fully explainedby writing alone.
Lastly, I must mention this essential fact. For those of you who think that polishers are
just supplementary to the swordsmith, The forging and polishing of a sword are ainextricable, and require each other in order to produce a Japanese sword. It becomes apure vessel of the gods. Therefore, polishing is also a spiritual pursuit. Around theswordsmith’s workshop, according to Shinto beliefs, there is a straw rope with white
paper tassels and a shrine mounted on the wall. This is a sacred boundary prohibiting
the entry of evil spirits into the sanctified workshop. The polisher’s workshop is nodifferent—it also has the sacred rope and shrine protecting the workshop.
This spirituality is exemplified with the use of water to purify the surface of thepolishing stone. It could have been a sad state of affairs had this aspect been lost after
the war.
This concludes the explanation of forging and polishing. However, before a samurai canwear his sword at his hip, it has to be passed to several other craftsmen before it iscompleted. These include: saya-shi (scabbard maker), nuri-shi (lacquerer), tsuka-maki(handle-wrapper), and the craftsmen who make the metal fittings. I will give a generalexplanation of these another time.