Asaoya Yaichi

タグ: Shikoku Japan

  • Tosa Knives and Kurouchi — Why the Black Finish Became So Common

    Tosa Knives and Kurouchi — Why the Black Finish Became So Common

    Ishizuchi Kanamono Manufactory

    Tosa Knives are often easy to recognise. Among polished Japanese knives, Damascus patterns and mirror finishes, many traditional Tosa knives have a much rougher appearance: a dark, almost black surface left above the cutting edge.

    This finish is called Kurouchi (黒打ち).

    Today, Kurouchi has become something many people associate with traditional Japanese knives. But while researching the history of Tosa Knives, I became curious about a more specific question: why does Kurouchi seem to fit Tosa knives so naturally?

    The answer is not as simple as I first expected.

    Tosa Knives Began as Tools for Working People


    From Agricultural Tools to Kitchen Knives

    To understand Kurouchi, we first need to understand where Tosa Knives came from.

    Kochi Prefecture has one of Japan’s strongest historical connections with forestry. Surrounded by mountains and forests, the region developed a long tradition of producing tools for agriculture and forestry.

    Tosa blacksmiths were not historically making only kitchen knives. They produced sickles, hatchets, saws and many other cutting tools required by farmers and forestry workers.

    According to Kochi City, records from the Chosokabe land survey of 1590 indicate that there were 399 blacksmiths in the region. Demand for agricultural and forestry blades later increased during the Edo period as these industries developed.

    These were working tools.

    They needed to cut well, survive hard use and remain practical.

    👉 INTERNAL LINK: Link here to “The History of Tosa Knives”

    That practical background is important when looking at the appearance of traditional Tosa blades.

    Tosa Knives and the Tradition of Free Forging

    One of the defining characteristics of Tosa cutlery is a technique known as Jiyu Tanzo (自由鍛造), or free forging.

    Rather than simply cutting a standard shape from sheet steel, Tosa blacksmiths traditionally forged blades according to their intended purpose. Different regions, working conditions and users could require different dimensions and shapes.

    Kochi Prefecture still describes this free-forging tradition as one of the defining characteristics of Tosa cutlery.

    In other words, the blade begins with its purpose.

    Its shape follows what the user needs.

    That philosophy helps explain why the sometimes rugged appearance of traditional Tosa Knives does not feel out of place. These blades developed from a culture where function mattered enormously.

    👉 INTERNAL LINK: Link here to “What Makes Tosa Knives Different from Other Japanese Knives”

    What Is Kurouchi on Tosa Knives?


    165mm Kiritsuke Thick Deba Aogami #2 Kurouchi Walnut Octagonal Handle

    Kurouchi literally refers to the dark finish left on part of a forged blade.

    During forging and heat treatment, a dark oxide scale forms on the steel. Instead of polishing the entire surface until it becomes bright and uniform, part of that dark surface is left visible while the cutting area is ground and sharpened.

    The result is the familiar contrast between the dark upper blade and the exposed steel closer to the edge.

    It looks rustic because, in a sense, it is.

    Kurouchi is not Damascus decoration painted onto a blade. The dark appearance comes from the blade-making process itself.

    👉 INTERNAL LINK: Link here to “Kurouchi Japanese Knives — What I Learned After Removing It”

    Why Did Kurouchi Become So Common on Tosa Knives?

    This is where I think we need to be careful.

    I could not find a reliable historical source that simply states: “Kurouchi became common in Tosa because of this one reason.”

    So I do not want to invent a history just because it makes a good story.

    What we can establish is that Tosa cutlery developed strongly alongside agriculture and forestry, that practical working blades were extremely important to the region, and that free forging became a defining part of its manufacturing culture.

    From that background, leaving part of the forged surface unpolished makes practical sense. It avoids the need to polish every part of a working blade purely for appearance while retaining the unmistakable character of forging.

    That does not prove that Kurouchi originated in Tosa.

    It almost certainly should not be described that way.

    But it does help explain why Kurouchi and Tosa Knives feel so naturally connected.

    👉 INTERNAL LINK: Link here to “Handmade Japanese Knives — Why No Two Are Exactly the Same”

    From Practical Finish to Japanese Character


    240mm Thick Deba Aogami #2 Kurouchi Walnut Handle

    Something interesting happened to me today here in Australia.

    I visited a café to show the owner some of our knives. When he saw one of the Kurouchi knives, he told me:

    “I want to have this kind of Japanese-looking knife.”

    That comment stayed with me.

    A finish that historically makes perfect sense on a practical forged tool now communicates something completely different on the other side of the world.

    It communicates Japan.

    The uneven black surface, the visible contrast with the sharpened steel and the slightly rugged appearance tell a story before anyone even uses the knife.

    For me, that is part of what makes Tosa Knives fascinating.

    👉 INTERNAL LINK: 壮大 Sōdai | The Knife That Stops People Before They Even Pick It Up

    Tosa Knives: Kurouchi Feels at Home in Tosa


    180mm Kiritsuke Aogami #2 Kurouchi Walnut Octagonal Handle

    I cannot say that Kurouchi was invented in Tosa, nor can I point to a single historical event that explains exactly why it became so strongly associated with Tosa blades.

    But perhaps that is not the most important point.

    Tosa cutlery grew from forests, farms, blacksmiths and people who needed reliable tools. Its tradition of free forging placed purpose before perfect uniformity.

    Kurouchi fits that philosophy remarkably well.

    What was once simply a practical way to finish a forged blade has also become part of the visual character that people around the world now recognise as distinctly Japanese.

    And today, standing in a café in Australia and hearing someone say, “This is the kind of Japanese knife I want,” I was reminded that the old character of Tosa still has the power to speak for itself.

    👉 Explore more:
    https://blog.asaoyayaichi.com.au

    👉 Visit our online store:
    https://asaoyayaichi.com.au

    Thank you for reading, and I hope to see you again in the next story.

  • 流通 | Tosa Knife History: 5 Surprising Ways Tosa Blades Spread Across Japan

    流通 | Tosa Knife History: 5 Surprising Ways Tosa Blades Spread Across Japan

    Ishizuchi Kanamono Manufactory

    When I started looking deeper into Tosa knife history, I became curious about something I had never really thought about before.

    We often talk about how Tosa blades were forged, the blacksmiths who made them, and the traditions that survived for hundreds of years. But after researching the history of Tosa knives recently, another simple question came to mind:

    How did these blades actually get from the blacksmiths of Tosa into the hands of people elsewhere in Japan?

    I sell Tosa knives in Australia today, yet I honestly did not know much about how Tosa blades were distributed in the past. So, as with many of the subjects on this blog, I decided to look it up.

    Tosa Knife History Started With More Than Kitchen Knives


    Japanese nata (traditional Japanese forestry blade)

    One thing that becomes clear when researching Tosa knife history is that we should not imagine Tosa as simply a historical kitchen-knife production area.

    Kochi Prefecture, historically known as Tosa Province, has long been closely connected with forestry. Its warm, rainy climate supported extensive forests, and timber became an important resource.

    Working in those forests required cutting tools.

    Axes, hatchets, sickles and saws were essential working tools, and the demand for agricultural and forestry blades helped Tosa’s blacksmithing industry develop. During the early Edo period, policies encouraging forestry and the development of new farmland increased this demand significantly.

    In other words, these blades were not originally objects made to sit beautifully in a display case. They were tools made to work.

    👉 INTERNAL LINK: Link here to “Tosa Knife History — From Samurai Era to Modern Tosa Knives”

    The Forests Helped Tosa Blades Travel

    This was the part I found particularly interesting.

    Tosa’s blade industry developed alongside its timber industry. One example is the Tosa saw. Historical information from the Tosa Cutlery Distribution Center explains that Tosa saw production developed around Kataji, an area along the Monobe River that served as a gathering point for timber.

    So there was a natural relationship between the forests, the workers, the movement of timber and the tools required to work with it.

    As Tosa’s forestry culture developed, its blades gained a reputation as practical working tools.

    Some accounts also describe forestry workers carrying Tosa-made tools when travelling to work in other regions. Other workers saw and used these blades, helping their reputation spread beyond Kochi.

    That is very different from modern marketing.

    There was no Instagram, online advertising or SEO. A tool could build its reputation simply because someone used it every day and trusted it.

    👉 INTERNAL LINK: Link here to “Kurouchi Japanese Knives — The Traditional Black Finish”

    Tosa Knife History and the Growth of Distribution


    A Traditional Tosa Blade Merchant

    By the Meiji period, the distribution story becomes clearer.

    Historical accounts of the Tosa blade industry indicate that around 1887, sales routes had expanded beyond the local area. They later spread throughout Shikoku and into the Chugoku region of western Honshu.

    As this happened, wholesalers dealing in forged blades began to develop, creating a more organised distribution system.

    I found this fascinating because it shows a transition.

    A blade could begin in a small workshop, pass through merchants and wholesalers, and eventually reach users far beyond the place where it had been forged.

    The blacksmith did not necessarily need to travel across Japan himself. A distribution network was beginning to connect regional craftsmanship with a much larger market.

    👉 INTERNAL LINK: Link here to “Handmade Japanese Knives — Why No Two Are Exactly the Same”

    Tosa Knife History Was Built Around Practical Tools

    The more I read about Tosa knife history, the more I feel that practicality is one of the keys to understanding Tosa blades.

    Their reputation was not created only by beautiful craftsmanship.

    These were blades expected to cut wood, clear land, harvest crops and perform demanding everyday work. Kitchen knives later became an important part of the tradition, but they belong to a much broader culture of forged working tools.

    Perhaps that is one reason I personally find Tosa knives so appealing.

    They can be beautiful, but they were never supposed to be beautiful only.

    👉 INTERNAL LINK: Link here to “Japanese Knife Finishes — What I Learned After 25 Years as a Chef”

    From Tosa to Australia


    A real koala spotted by Asaoya Yaichi 🐨

    And this is where researching the past made me think about what I am doing today.

    Hundreds of years ago, Tosa blacksmiths made blades for people working in the forests, farms and kitchens of Japan. Over time, those blades travelled farther through workers, merchants and developing distribution networks.

    Today, the distance is much greater.

    I work directly with Ishizuchi Kanamono Seisakusho and bring handcrafted Tosa knives from Japan to Australia.

    Of course, modern shipping and online stores make distribution completely different. But when I look at the bigger picture, perhaps the basic idea has not changed as much as I expected.

    A blacksmith makes a tool.

    Someone believes in that tool.

    And then someone carries it to the next person who will use it.

    I did not know much about this side of Tosa knife history before researching it. Now, every time I unpack a shipment of Tosa knives here in Australia, I think I may be participating in a very small continuation of a journey that began long before me.

    👉 INTERNAL LINK: Link here to “The True Value of Japanese Knives — Why a Good Knife Can Last for Decades”

    👉 Explore more:
    https://blog.asaoyayaichi.com.au

    👉 Visit our online store:
    https://asaoyayaichi.com.au

    Thank you for reading, and I hope to see you again in the next story.

  • 土佐 Tosa | The Powerful History of Tosa Knives I Wanted to Know

    土佐 Tosa | The Powerful History of Tosa Knives I Wanted to Know

    When you work with something every day, sometimes you forget to ask where it actually came from.

    I sell Tosa knives in Australia, sourcing handcrafted Japanese knives directly from Shikoku, Japan. I have also spent more than 25 years working as a chef in Japan and Australia. I know how these knives feel in the hand, how they sharpen, and how they perform in a professional kitchen.

    But recently, I realised there was something I wanted to understand better.

    How did Tosa knives actually begin?

    I knew that Tosa had a long history of blacksmithing, but I wanted to look deeper into why this particular part of Japan became known for forged blades. What I found made me appreciate the history behind these knives even more.

    The History of Tosa Knives Goes Back Centuries

    Ishizuchi Kanamono Manufactory

    The story of Tosa knives is closely connected to the geography and working life of Kochi Prefecture, historically known as Tosa Province.

    Kochi is a mountainous region with extensive forests. For generations, forestry was an important part of life there, and people needed strong, dependable tools for cutting trees, clearing land and working in the mountains.

    That naturally created demand for forged tools such as axes, hatchets, sickles and saws.

    The history, however, goes back even further.

    Sword-making techniques are said to have reached Tosa during the Kamakura period. By 1590, the Chōsokabe Land Survey Records documented 399 blacksmiths in Tosa Province.

    That number surprised me.

    It shows that blacksmithing was already deeply established in the region more than 400 years ago.

    How Tosa Knives Grew With Forestry and Agriculture


    From Agricultural Tools to Tosa Knives

    The major development of Tosa forged blades came during the early Edo period.

    In 1621, reforms by the Tosa Domain encouraged the development of forestry and new agricultural land. As forestry and farming expanded, so did the need for reliable cutting tools.

    Blacksmiths responded to that demand.

    Over time, production increased and techniques improved. What began as tools essential for daily work gradually developed into what we now recognise as the tradition of Tosa Uchihamono, or Tosa forged blades.

    This is one thing I find particularly interesting about Tosa.

    The tradition was not created simply to make beautiful objects.

    These were working tools.

    They had to cut. They had to survive hard use. And they had to be practical enough for people who depended on them for their livelihood.

    👉 INTERNAL LINK: Read more about why handmade Japanese knives are never exactly the same

    Tosa Knives and the Tradition of Free Forging


    Kiritsuke Aogami #2 Kurouchi Walnut Octagonal Handle

    Another characteristic that caught my attention while researching Tosa knives was something known as jiyū tanzō, or “free forging.”

    Rather than relying entirely on fixed moulds, Tosa blacksmiths traditionally forged different shapes and sizes according to their intended purpose.

    That flexibility made sense in a region where people needed many different kinds of blades for forestry, agriculture and everyday life.

    Even today, you can see something of that character in handcrafted Japanese knives.

    Small differences in hammer marks, blade shape and finish are not necessarily imperfections. To me, they are reminders that a knife was made by human hands rather than simply coming from an automated production line.

    👉 INTERNAL LINK: Read more about Japanese knife finishes and what they really mean

    👉 INTERNAL LINK: Read more about Kurouchi Japanese knives and the traditional black finish

    From Traditional Tosa Blades to Modern Kitchen Knives


    180mm Santoku VG10N 33 Layer Damascus Green Marble Handle Rainbow Spacer

    Today, Tosa knives are known far beyond Kochi.

    In 1998, Tosa Uchihamono was officially designated as a Traditional Craft of Japan. The tradition includes not only kitchen knives but also axes, sickles, hatchets, saws and other working blades.

    Modern Japanese kitchen knives have naturally evolved as well.

    Today we can find traditional carbon steels such as Aogami alongside stainless steels and modern powder metallurgy steels. Handles, finishes and blade styles have changed to suit contemporary cooks, but the connection between Japanese knife making and traditional forging remains.

    👉 INTERNAL LINK: Learn more about Aogami and Shirogami steels

    👉 INTERNAL LINK: Read my guide to Ginsan steel and why I like it for kitchen knives

    For me, that combination is what makes the history of Tosa so interesting.

    It is not simply a tradition frozen in the past.

    It has continued to evolve.

    Why the History of Tosa Knives Matters to Me


    Wooden Box for Traditional Knives

    After looking into this history, I see the knives I work with a little differently.

    I started Asaoya Yaichi because I wanted to bring genuine handcrafted Japanese knives from Shikoku to Australia. As a chef, my first concern will always be practical: does the knife actually work well in a kitchen?

    But there is another side to it.

    Learning about Tosa knives reminded me that Japanese blades did not develop only as kitchen tools. Their history is connected to forestry, agriculture, sword-making knowledge and generations of blacksmiths adapting their skills to what people actually needed.

    That history does not automatically make every knife perfect.

    But I think understanding where these traditions came from gives us a better appreciation of why Japanese forged knives are the way they are today.

    Perhaps that is what I like most about the history of Tosa.

    These blades were never meant to exist only behind glass.

    They were made to be used.

    And more than 400 years later, that practical spirit can still be found in the Japanese forging traditions that continue across Shikoku today.

    👉 Explore more:
    https://blog.asaoyayaichi.com.au

    👉 Visit our online store:
    https://asaoyayaichi.com.au

    Thank you for reading, and I hope to see you again in the next story.