To refresh your memory - or in case you didn't read July's article - let me again draw a passage from Kanzan Satou's The Japanese Sword: "The techniques of forging which were evolved by the Japanese smith are unique and can bear comparison with those in any other part of the world. From earliest times the functional attributes sought in a Japanese blade have been unbreakability, rigidity, and cutting power. The more purely aesthetic qualities sought by modern collectors might seem to be at variance with these severely practical requirements but in fact it is in its fulfillment of demanding technical norms that the essential beauty of a Japanese sword lies. It is obvious that unsnappability depends on the iron being soft while rigidity depends on its being hard, as does cutting power. However if the iron is hard it will snap easily and if it is soft it will not cut well. The combination of these contradictory qualities is the greatest achievement of Japanese forging and tempering techniques..."
In order to meet those technical requirements, the Japanese sword has a hard outer skin, formed by folding over and hammering out the same piece of high-carbon steel many times. This outer skin is wrapped around a softer inner core, formed by a different process of folding low-carbon steel. A cutting edge (hamon) is formed by covering the blade with clay containing charcoal ash which is scraped away - in some places partially and in others completely - from the edge of the blade prior to heating. The sword is then cooled by dipping it in water, but the clay covering causes the exposed areas to cool more quickly, producing different crystalline compounds which result in the cutting edge being the hardest part of the blade.
In Gifu Prefecture, Fujiwara-san's family has been making swords the traditional way for 25 generations. A sign to the left of the door of his smithy proclaims that the Fujiwaras were sword makers to the Tokugawa family, who ruled Japan for more than 250 years. Today, Fujiwara-san makes swords with three apprentices, who have been with him from 2-8 years. These apprentices explained the sword making process to my friends and I, and then - with the master himself - demonstrated the process of hammering and folding the iron and even let us take turns hammering the iron ourselves.
