From the 13th century when the legendary founder and pioneer Motoshige first began making swords in Seki, they were much appreciated throughout Japan. Warlords praised them highly, as we may gather from the old saying: "They neither break nor bend and cut marvelously well."
Down through the ages the craftsmen of Seki remained faithful to the secrets of their ancestral art as well as to the Buddhist teaching of Hajya Kensho, which translated literally means: "Smash vice and iniquity, and restore light to righteousness." Clad in their white robes to keep themselves free from defilement, these men forged blades in a spirit of inner emptiness, a characteristic goal of Buddhist spirituality which may explain why so many master sword-makers went on to become famous performers of No and of Kyogen, the comical counterpart of No.
Even today the swordsmiths of Seki carry on this 700-year tradition. Some of them say that the flame is the most important element in producing a blade. They say that its color or appearance teaches them everything they need to know, from the state of the steel to the precise moment when the bellows must be brought into play. The flame is their master and friend, and through it they remain in touch with the spirit and art of their predecessors.
Japanese Sword Making Process
1. Tatara Steel: A mixture of iron filings and charcoal is heated to produce a solid amalgam. Only the part of the steel called tamahagane will be used in making the sword.
2. Tsumiwakashi: The tamahagane is heated and forged into a flat shape 3 to 6 millimeters thick. It is then broken into small pieces in order to test its hardness. These pieces are melted down separately according to their hardness at 1,300 degrees and made into a single slab of steel. By wrapping this slab in dampened paper, then covering it with mud and ash, the heat is transmitted evenly on the surface as well as inside.
3. Orikaeshi Tanren: The steel heated to 1,200 to 1,300 degrees is repeatedly hit with a large mallet and folded over. During this process, the impurities in the steel are worked out and fly off as sparks.
4. Katame (Tsukurikomi): Pieces of steel of various degrees of hardness are combined. A special characteristic of the Seki tradition is a production method called shihouzume that involves packing from four directions.
5. Sunobe: The hardened steel is heated and stretched into the form of blade by hitting with a small hammer.
6. Hizukuri: The stretched steel is heated again and hammered so as to form the cutting edge and the blunt edge of the blade.
7. Arashiage: A rasp is used to smooth out any roughness on the blade.
8. Tsuchioki and Tsuchitori: The blade is then coated with a mixture of clay and pine charcoal which will leave a wave-like pattern on the cutting edge.
9. Yakiire: After the entire blade is evenly heated, it is plunged into water. The portion of the blade that was thinly coated with the baking clay will heat up to a higher temperature and so will be more strongly tempered.
10. Aratogi (Kaji-oshi): Once the tempering process is finished, the swordsmith himself does some preliminary grinding to test the quality of the blade. Then he works on the part that will be inserted into the haft of the sword before passing it on to the grinder.
Reference: Swords Owned by the City of Seki, Seki, Gifu Prefecture.