KIREAJI Knowledge

  • Explore the World Behind Japanese Knives

    Japanese knives are more than tools—they are the result of centuries of tradition, shaped by unique materials, regions, and craftsmanship.
    At KIREAJI, this Knowledge section is designed to help you understand not only what Japanese knives are, but why they are made the way they are.

  • Here, you will discover the stories, principles, and techniques that shape every blade:
    from the history of Japanese knives and the regional styles of Sakai, Seki, and Tsubame-Sanjo,
    to the materials, structures, steels, and craftsmanship that define their performance.

  • Whether you are a chef, a home cook, or a curious learner, this is where your journey begins.
    Deepening your understanding will change how you see, use, and appreciate a Japanese knife—
    and may even inspire you to share its spirit with others.

History of Japanese Knives

  • Where Tradition, Craft, and the Spirit of the Blade Begin

    The history of Japanese knives is not only a story of tools—
    it is a story of swordsmiths, philosophy, regional cuisine, and the Japanese way of seeing the world.
    From ancient court kitchens to modern Michelin-star restaurants, each blade carries centuries of evolution.


    In this section, you will discover how Japanese knives emerged from the legacy of the samurai,
    how regional cuisines shaped distinct blade styles,
    and how craftsmen transformed the spirit of the sword into the soul of the kitchen knife.

    For anyone who hopes to become a Japanese Knife Evangelist,
    understanding this history is essential.
    It reveals why Japanese knives are unique,
    why their forms and functions developed as they did,
    and why they continue to inspire chefs across the world today.

    Explore the origins, philosophy, and cultural depth behind every blade—
    and let this history deepen your connection to the knives you use and share.
History of Japanese Knives

Japanese Knife Market

  • Why the World Is Turning to Japanese Knives — And Why Your Voice Matters

    The global rise of Japanese knives is not just a market trend—it is a cultural movement.
    While domestic demand in Japan continues to shrink, interest abroad is growing faster than ever.
    Chefs, collectors, and home cooks around the world are discovering the precision, story, and soul behind these blades.


    In this section, you will learn why Japanese knives are rising globally,
    how a shrinking home market shaped their journey,
    and why international demand is now essential to preserving the craft.

    For anyone who wants to become a Japanese Knife Evangelist,
    understanding this market shift is powerful knowledge.
    It reveals your role in keeping the tradition alive—
    how your curiosity, your appreciation, and even your conversations
    help carry Japanese craftsmanship into the future.

    Explore the forces behind this transformation and see how each knife you learn about, use, and share
    becomes part of a much larger story.
Japanese Knife Market

Three Major Knife Regions in Japan

  • Three Regions, One Heritage — The Diverse Heart of Japanese Knife Craft

    Japan’s knife-making tradition is shaped by three iconic regions: Sakai, Sanjo, and Seki.
    Each carries its own history, techniques, and philosophy—resulting in a remarkable diversity of blades trusted by chefs and home cooks around the world.

    In this section, you will learn how each region developed its distinct identity:
    why Sakai became the home of professional, single-edged craftsmanship,
    why Sanjo forged its legacy through resilience and practical innovation,
    and why Seki blends swordsmith heritage with modern mass-production.

  • For anyone who hopes to become a Japanese Knife Evangelist,
    understanding these regional differences is essential.
    It reveals how geography, cuisine, and craftsmanship shaped each blade,
    and why Japanese knives today offer such a rich spectrum of performance and character.

    Explore these three regions—and see how each one contributes to the living culture of Japanese knives
    that you can learn, use, and share with the world.
Three Major Knife Regions in Japan

Japanese Knife Structure

  • More Than an Edge — The Structure That Defines Japanese Knives

    The structure of a Japanese knife is not just engineering—
    it is a blend of tradition, philosophy, and purpose, refined over centuries.
    From the elegant single-edge design to the versatile double-edge form, the way a knife is shaped reveals how Japan views food, craftsmanship, and precision.

    In this section, you will explore the foundations of Japanese knife geometry:
    the difference between single-edge and double-edge blades,
    the cultural philosophies behind Eastern and Western cutting styles,
    and the traditional constructions such as Honyaki, Kasumi, Zenkou, and more.

  • For anyone who hopes to become a Japanese Knife Evangelist, understanding knife structure is essential.
    It explains why Japanese knives cut differently,
    why they require specific sharpening methods,
    and why each blade shape has a clear culinary meaning.

    Discover the craft behind the edge—
    and see how structure transforms a knife from a tool into an expression of culinary culture.
Japanese Knife Structure

Japanese Knife Materials

  • Steel Is the Heart of the Knife

    Behind every Japanese knife, there is one decisive element: the steel at its core.
    Two knives may look similar on the surface, yet their sharpness, edge retention, and care requirements can be completely different—all because of the steel they are made from.

    In this section, you will learn how knife materials evolved
    from simple iron, to high-performance carbon steels, to modern stainless and “super” steels.
    You will also discover why Yasuki steel, Ginsan, ZDP-189, and other advanced alloys are so highly respected by chefs around the world.

  • For anyone who hopes to become a Japanese Knife Evangelist,
    understanding knife materials is more than technical knowledge.
    It allows you to choose the right knife for your cooking style,
    care for it with confidence,
    and explain to others why a blade feels—and performs—the way it does.

    By exploring the steels behind Japanese knives,
    you are not just learning specifications.
    You are learning the language that connects craftsmen, chefs, and future knife lovers through a single blade.
Japanese Knife Materials

Yasuki Steel

  • The Legendary Steel Behind Japan’s Finest Knives

    Among all the materials used in Japanese knife-making, few carry the weight, history, and cultural meaning of Yasuki Steel. To understand why Japanese knives cut with such purity—and why Sakai blades are trusted by chefs around the world—one must begin with this exceptional steel. Yasuki Steel is more than a metal; it is a distillation of purity, sharpness, and the spirit of Japanese craftsmanship, refined from ancient Tatara ironmaking and carried forward by generations of master smiths.

    Produced in Yasugi City, this steel evolved into White Steel, Blue Steel, and Ginsan, each offering its own character. White Steel pursues the cleanest, most delicate edge. Blue Steel enhances durability and endurance. Ginsan bridges traditional sharpness with modern rust resistance. These variations express different philosophies of cutting, yet all share the same foundation: precision, purity, and the pursuit of excellence.

  • For those who wish to become true Japanese Knife Evangelists, Yasuki Steel offers more than technical understanding. It reveals why Sakai knives glide so effortlessly through ingredients, why sharpening can become a meditative craft, and why a blade can feel like a living partner rather than a simple tool. The steel itself becomes a gateway to appreciating the beauty, discipline, and cultural values inherent in Japanese cuisine.

    Today, Yasuki Steel faces an uncertain future. Corporate restructuring and shifting industrial priorities place pressure on the continued production of these high-purity specialty steels. In such a moment, using and sharing the story of Yasuki Steel carries deeper meaning. When you cook with a Yasuki Steel knife, you are not only experiencing extraordinary sharpness—you are holding a piece of Japanese cultural heritage in your hands.

    To learn about Yasuki Steel is to connect with a tradition that has shaped Japan’s blades for centuries. By appreciating this steel and passing its story forward, we help protect a craft that deserves to endure.
Yasuki Steel

Part of a Japanese Knife

  • Understanding the Form, Function, and Subtle Beauty Behind Every Blade

    A Japanese knife is far more than a cutting instrument. It is a precise, thoughtfully engineered tool shaped by generations of craftsmen who refined every curve, line, and surface to achieve exceptional sharpness, balance, and control. From the slender point of the tip to the quiet hollow on the back, each element carries a purpose—one that directly affects how the knife moves through ingredients and how it feels in your hand.

    What makes Japanese knives especially compelling is how form and function are inseparable. The kissaki guides delicate work at the very front of the blade. The hasaki carries the razor edge that defines Japanese cutting. The shinogi controls the blade’s geometry and sharpening accuracy. The subtle urasuki on the back reduces friction and improves food release. Even the wooden handle is carefully selected for comfort, balance, and responsiveness. These are not decorative details; they are deliberate design choices grounded in centuries of culinary culture.

    This guide introduces the structure of a traditional Japanese knife and explains how each part contributes to performance in real cooking. We also preserve the original Japanese names—kanji and romaji—so that you can recognize them when watching sharpening tutorials, learning from craftspeople, or deepening your understanding as a future Japanese Knife Evangelist. Knowing these terms allows you to appreciate the knife not as a simple tool, but as a finely tuned instrument shaped by history, philosophy, and craftsmanship.

  • A Japanese knife reveals its true character the more you understand it. By learning the names, the roles, and the craftsmanship behind each part—front and back—you begin to see how every detail supports the blade’s remarkable precision. The geometry that creates effortless slicing, the intentional hollows that guide ingredients away from the steel, the reinforced handle joint that grows stronger over time—nothing is accidental. Everything is designed to help the knife perform as an extension of your hand.

    Whether you are discovering Japanese knives for the first time or deepening your knowledge as an experienced user, this guide will help you see the anatomy of the blade with new clarity. Every part, from the kissaki to the urasuki, forms a story of technique, culture, and refinement—one that continues to inspire chefs and enthusiasts around the world.
Part of a Japanese Knife

The Making of Japanese Knives

  • From Fire and Steel to a Knife That Feels Like an Extension of Your Hand

    Every Japanese knife begins as simple steel—but it only becomes a true blade through fire, water, and human hands. Behind its smooth cutting feel and quiet confidence on the board lies a long, invisible journey: hours of hammering, careful heat treatment, patient sharpening, and the final joining of blade and handle. What looks like a single object in your kitchen is in fact the result of many craftsmen, each dedicating a lifetime to just one part of the process.


    In Sakai and other traditional regions, a knife is not made by one person alone. It passes through distinct stages—forging, heat treatment, sharpening, and handle mounting—with each step entrusted to a specialist. The blacksmith gives the blade its “skeleton” and potential. The heat-treatment master awakens its hardness and resilience. The sharpener reveals its character on stone, and the handle maker allows the knife to sit naturally in your hand. Together, they turn raw steel into something that moves as if it were part of you.

  • For anyone who hopes to become a Japanese Knife Evangelist, understanding how a knife is made changes the way you see and speak about it. You begin to feel the difference between mass-produced steel and a blade that has been shaped by judgment, experience, and care. You notice how the edge glides, how the balance feels, how the knife responds when you sharpen it—and you know that none of it is an accident.

    This section takes you behind the scenes of Japanese knife-making, from the first strike of the hammer to the moment the handle is fitted. By learning how each stage builds on the last, you will not only deepen your appreciation for the knives you use, but also gain the language and insight to share their story with others. A Japanese knife is more than a product to buy; it is a craft you can understand, respect, and help carry into the future.
The Making of Japanese Knives

Sharpening Knives

  • Why Japan Alone Developed a Deep Culture of Whetstone Sharpening

    When a knife becomes dull, many people around the world simply replace it.
    But in Japan, knives are not discarded — they are restored, refined, and respected through sharpening.
    This is not merely maintenance. It is a cultural tradition shaped by Japan’s geology, spirit, and aesthetics.

    Sharpening with whetstones did not emerge by accident. It became possible only because Japan was blessed with rare natural finishing stones, cultivated a philosophy that treats tools as partners, and developed an artistic view of sharpness that goes beyond function. Together, these elements formed a sharpening culture found nowhere else in the world.

  • This page takes you into that culture — why it exists, what makes it unique, and how it continues today through your own hands. By understanding the meaning behind sharpening, you will see your knife not as a consumable item, but as a craft you can deepen, care for, and pass on.
Sharpening Knives

Epilogue — Knowledge That Becomes Meaning, and Meaning That You Pass On

  • The more you learn about Japanese knives, the more you begin to see something beyond steel and sharpness.
    You start to recognize the intentions of the craftsmen, the precision behind every line, and the quiet discipline that shapes each blade. Knowledge turns tools into stories, and stories reshape the way you cook, observe, and share.

    And this is where the journey truly begins.

    Learning is the first step — but the culture lives only when people speak about it, pass it on, and inspire others.
    When you share what you’ve discovered — why steel matters, how a blade is forged, what makes sharpening an art — you are doing more than explaining facts. You are giving someone a new way to see the world of Japanese knives.

  • A single insight you share may be the spark that awakens someone else’s curiosity.
    This is how traditions continue. This is how craftsmanship survives.
    And this is how Japanese knife evangelists are born.

    At KIREAJI, we invite you not only to know Japanese knives, but to carry their stories forward — to the chefs around you, to friends who love cooking, and to the next generation of curious learners.

    Because your voice, your understanding, and your passion can help ensure that this 600-year tradition does not fade, but grows.

    Knowledge becomes meaning.
    Meaning becomes action.
    And action becomes legacy.

    Welcome to the beginning of your journey as a Japanese knife evangelist.

Our Story

  • Tradition of Sakai, in Your Hands

    "Where can I find a truly great knife?"
    We started KIREAJI to answer that question. While the number of skilled craftsmen is declining in Japan, many people overseas are seeking authentic blades. With that in mind, we carefully deliver each knife—bridging tradition and kitchens around the world.
Our Story