Metal One Corporation - Value One - Metal Culture

From Value One, Spring 2007 No. 16

Situated in the northeastern part of Kochi Prefecture on the Pacific side of Shikoku, Kami City is blessed with rich forests that have grown in a warm climate with high rainfall. The area has been known as a major source of precious wood since ancient times and used to be called Tosa. Tosa Uchihamono (forged cutlery) items have played a vital role in the lives of people in the area in their efforts to develop the hillsides and flatlands, and cut the forest trees.

Tosa Uchihamono includes mostly tools such as axes, sickles and matchets for use in farming and forestry. It is characterized by its ryoba (double edge) and is produced using jiyu tanzo (free forging) techniques, both of which derive from the techniques involved in forging a Japanese sword. First, a soft piece of iron (jitetsu) the size and shape of a cigarette is heated to approximately 800°C, and is then vertically divided through its center using a chisel. A hard layer of Yasuki steel is placed between the divided layers to form the edge. This is then heated again at approximately 1,000°C, and when red hot, hit with a hammer to forge-weld the jitetsu and steel. As this "heat and hit" cycle is repeated, the rectangular jitetsu is rapidly transformed into an axe, sickle or matchet. The hole known as hitsu where the handle is attached to the axe blade is not drilled, but bored with a chisel against the jitetsu. Free forging of a complex shape reflects the essence of the smith's skills. Mr. Satoshi Yamashita, a master craftsman of Tosa Uchihamono says: "Whether an Uchihamono product cuts well or not greatly depends on the temperature control in quenching and annealing." If it is not heated enough, it will become blunt, but if the blade is heated too much, it will become brittle. Joining materials that are different in terms of hardness by heating, hammering and forging serves to further strengthen the function of Tosa Uchihamono, the products of which neither snap nor bend but cut sharply.

A layer of Yasuki steel is inserted between divided layers of jitetsu, which is then heated and hammer-welded. The ryoba is forged during the wakashitsuke (welding by hammering at near-melting point) process.

The red hot blade is hammered and shaped. The pressure of hammering reinforces the useful characteristics of steel.

A matchett with a polished finish and the smith's signature. The steel edge shines dimly.

	Tosa Hamono Distribution Center (cooperative) 109 Kamikaida, Tosayamada-cho, Kami-shi, Kochi Tel: +81-887-52-0467 Open: 8:30-17:00 on weekdays 10:00-16:00 on Saturday, Sunday and national holidays

Kochi Prefecture is Japan's biggest producer of Uchihamono for use in farming and forestry. At the Tosa Hamono Distribution Center, which is a cooperative, you can buy Tosa Uchihamono items after first confirming the quality of the products. It is mostly young smiths who play a central role in the development and sale of new types of Uchihamono including uniquely shaped small kitchen knives.