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What is Shinshu Uchihamono?

Shinshu Uchihamono are forged blades that are formed by heating iron and beating it repeatedly with a hammer. Each craftsman forges each piece and each knife by hand to create a product. Therefore, mass production is not carried out. Shinshu sickles have a wider and larger sickle blade than sickles made in other regions, and have a heavy weight. Uchihamono is belong to cutlery, not to knife industry, so this traditional craft has various types of cutlery other than knives like Chiba Koshugu and Echizen Uchihamono (=Echizen cutlery; recently knife is the main production).

However, when you hold it in your hand, you will be surprised at how light it is. The secret lies in the thin blade that has been carefully cut. It is called a “razor sickle” because of its sharpness, ease of use, and durability, which are unique characteristics not found in any other production area. In particular, the extremely thin steel (hagane) part, which is 1/6 the thickness of the entire sickle, can be said to be the greatest feature.

Source:https://www.shinanonet.jp/item/KBP-50b/

History of Shinshu Uchihamono

Polished technology that has continued since before the Edo period

About 450 years ago, at the time of the Battle of Kawanakajima, villagers learned the art of forging from blacksmiths who had moved to the area to repair weapons and swords, and used their skills to make farming and forestry tools. Gradually, the technique was passed down from apprentice to apprentice, and from child to grandchild, as improvements were made. 

Evolution for Easier Use

In the late Edo period (1603-1868), a field smith named Senemon Kubo of Kashiwara Village devised a unique technique called “shibazuke,” which aimed to mow grass from the root, and to draw the mowed grass toward the hand, and “tsuri,” which curved the blade surface inward so that the hand could be maintained even with a thin blade. Around the same time, Arai Tsuemon of Furuma Village is said to have improved the double-edged sickle to a single-edged, thin-bladed one. The sickle invented by these two men became the prototype of today’s Shinshu sickle, and the extremely thin steel (hagane) part, 1/6 the thickness of the entire sickle, is the basis of the sharpness of the sickle.

Sold Nationwide

From the end of the Edo period to the Meiji period (1868-1912), some people began to make their living selling sickles, and wholesale dealers who divided production and sales into separate businesses were established. In 1888, the Shinetsu Line of the Japanese National Railways was opened, and as a result, sickles were sold throughout the country. In March 1978, the company was designated as a “traditional craft” and has continued to grow. Our products are not limited to farming and forestry tools, but we also manufacture kitchen knives and other blades in general, as well as other products. 

Technological Reforms

Power Hammer in the old days, sickle manufacturing was a cottage industry, small in scale, with one to three employees at most. Most sickle manufacturing was done by a husband and wife team. The work was done in an old-fashioned way, almost entirely by hand, with the master beating the sickle with a hammer and the wife serving as a partner.

In the 1940s, a Canadian missionary, Alfred Russell, who lived in a foreign villa near Lake Nojiri, was a member of the family. Russell Stone, a Canadian and missionary living in a foreign villa near Lake Nojiri, in the 1940s. In order to free housewives from hard labor, he built a sickle factory equipped with a power hammer together with Tsuneo Watanuki and others in Koma, and after testing the technology and capabilities, he set his sights on mechanization. This power hammer was then widely used and contributed greatly to the increase in production.

Manufacturing Process

1. Hammering

After making the steel and the base iron, the steel is welded to the base iron to form the cutting edge. Forge welding” is the process of joining two different metals by applying heat and pressure, and refers to heating the steel and the base iron and hitting them together with a hammer. Steel is thinner than base metal. For example, 2mm-thick steel is forged and welded to 9mm-thick ferro-iron.

2. Komi Bending

Komi” is the part that sticks out to insert the sickle blade into the handle. The part that will become the “Komi” is struck and bent.

3. Koshidashi

The bent part is spread out by hitting it.

4. Spreading

The blade is carefully hammered and spread out to the approximate shape of the sickle.

5. Oshikiri

Prepare the edge of the blade and adjust the size.

6. Making the edge of the sickle

Prepare the edge of the sickle.

7. Rough Striking

After the sickle is heated in a furnace to about 700 degrees Celsius, it is hammered with a hammer and a mallet until the thickness of the “hira” is uniform. It takes skill to make the thickness uniform.

8. Rough polishing

Iron oxide and debris on the surface of the sickle are removed and the surface is cleaned.

9. Marking

Engraving of trademarks and quality markings is done in the designated positions.

10. Preliminary Preparation

Koranashi” is the process of heating the sickle to approximately 500 degrees in a furnace and then hammering it by hand to smooth the surface. This “Ko-Narashi” gives Shinshu Uchihamono its characteristic toughness.

During the “Ko-Narashi” process, “Shibazuke” and “Tsuri”, which are unique to Shinshu Kamara, are also made. Shibazuke” is a process to make an angle between the sickle blade and the comma so that the cut grass will come closer to the hand, and “Tsuri” is a process to curve the blade surface inward so that the hand will not be distorted even if the blade is thin.

11. Medium sharpening

The steel portion is polished with a medium grindstone.

12. Quenching

The surface of the sickle is coated with mud, heated to about 780 degrees Celsius, and then placed in a water tank to cool rapidly. This “quenching” process changes the structure of the steel and makes it harder. This hardening is said to “put the soul into the blade. The reason for applying mud is that the mud cools the sickle evenly during the “quenching” process.

13. Tempering

This is the process of making the steel have proper tenacity. Since hardness alone can cause blade spills, giving the steel a stickiness prevents blade spills and keeps the blade sharp.

14. Yori-Tori (removal of the edge)

Since steel and base iron have different expansion coefficients, warping and bending occur during quenching. This process corrects warping and bending.

15. Edge grinding and polishing/glazing

The blade is polished with a hafu cloth to bring out the luster.

16. Rust prevention

Varnish or camellia oil is applied to prevent rusting.

17. Attach the handle

Attach the sickle blade to the handle.

This traditional craft with a long history has been handed down from apprentice to apprentice, with improvements being made, and even today, in the 21st century, the Koma district of Shinano-cho is still dotted with workshops of craftsmen who make hammered blades using the same traditional techniques. The sharpness, ease of use, and durability of these blades are outstanding along with Seki-knife and Sakai-knife, and they have fans all over Japan.