Why a Japanese Knife Is the Best Choice for Chefs: Buying Guide
“Everything You Need to Know About Japanese Knives”
Over the past decade, Japanese cooking techniques have gained the attention of chefs worldwide. With the growing popularity of the cuisine, the interest in Japanese chef knives has also grown. Delicate Japanese cuisine requires a sharp blade to preserve the fresh flavors and appearance of ingredients. Cutting with a dull knife damages the cell walls of ingredients and accelerates discoloration and wilting. The combination of different metals and expertise of the blacksmith’s knife-forging methods by hand make these incomparably sharp blades possible. Nowadays you can find Japanese knives in commercial kitchens being used by chefs for making precise cuts.
Why a Japanese Knife Is the Best Choice for Chefs: Table of Contents1, Japanese Knive Brand
2, Types of Japanese Knives
3, Top Recommended Knives
4, Cultural Background
5, Differences from Other Knives
6, Types of Materials Used
7, Knife Crafting Techniques
8, Background on Knife Accessories
1, Japanese Knife Brands
Korin’s vast selection of the best Japanese chef knives were carefully selected by our late master knife sharpener and the founder. The steel used for these knives are made to be easily sharpened and retain a long lasting edge for culinary professionals. They are crafted to have an unparalleled sharp fine blade as traditional Japanese cuisine demands attention to detail. All are time tested with superb quality that is perfect for fast-paced commercial kitchens. (Interested in a custom chef knife? You can also design custom-made Nenohi knives on our website.)
More Detail : KORIN
More Detail : Togiharu
More Detail : Suisin
More Detail : Misono
More Detail : Nenox (Nenohi)
More Detail : Masamoto Sohonten
More Detail : Masanobu
More Detail : Glestain
More Detail : MAC
More Detail : Sugimoto
More Detail : Kochi
Traditional Japanese knives were originally derived from Japanese sword craftsmanship. The techniques have been handed from generation to generation and perfected over time.
A sharp blade slices through ingredients effortlessly, but a dull blade will damage the cell walls of ingredients, altering their texture and flavor. For example, if one tries to chiffonade basil with a dull knife, it will turn black almost instantly. With a thin sharp knife, the same chiffonade will retain its vibrant green color for hours or even days. The single-edged blade is a unique feature of traditional Japanese knives, which is directly linked to Japanese cuisine and history. Traditional Japanese cuisine aims to preserve and accentuate the true flavors of fresh and seasonal ingredients, making a sharp knife is essential to this process.
Western-style Japanese knives, such as the Gyuto Japanese chef’s knife, have a blade edge that is sharpened on both sides of the blade. This edge style is commonly referred to as a double-edged, double ground or double beveled blade. It is a stronger blade configuration than the single-edged blades of traditional Japanese knives, and Western-style knives are perfectly suited for any kitchen.
These unevenly beveled edges are made possible by innovations in steel-making, tempering and edge crafting employed by Japanese manufacturers; a lower grade steel would not hold this angled edge design and would soon dull, and a blade formed with less flexibility would chip or crack when sharpened so thinly.
The majority of Western knives on the market today have a 50:50, or symmetrical “V”-shaped blade that is sharpened the same way on both sides. Although the 50:50 edge is convenient to re-sharpen, many Japanese Western-style knives are sharpened to a thinner, asymmetrical edge. By concentrating the sharpening on the face of the blade at a steeper angle than on the back side, a thin cutting edge is created that approaches the sharpness of the traditional single-edged design.
The angles on this uniquely Japanese edge style can be expressed in ratios such as 70:30, 60:40, and 90:10, comparing the angle of the bevel and the amount of sharpening performed on the face of the knife to the back. The most common edge shape in the Korin Collection of Western-style knives is in the range of 70:30 for right-handed users.
In the 16th century, Sakai in Osaka prefecture prospered as one of Japan’s greatest commercial centers, trading with Ming-dynasty Chinese merchants as well as with Portuguese and Spanish seafarers. Today this port city on Osaka Bay is known for kofun tumuli (megalithic tombs), and the manufacture of Japanese knives.
Many of the burial mounds were constructed from the latter half of the fourth century to the first half of the sixth. The Mozu group in Sakai is home to some of the largest keyhole-shaped kofun ever buil. Of the more than 100 believed to have been constructed, 44 remain today. Largest among them is the Daisenryo tumulus, constructed in the early half of the fifth century. Covering 10 hectares, it is also the largest in the world. Sakai considers it one of the world’s three great tombs, alongside the Great Pyramid of Khufu in Giza, Egypt, and the tomb of Emperor Qin Shihuang in China.
By comparison Sakai holds just seven percent of the market in Japan for knives overall, but with regard to top-of-the-line products for professional use, its share is a whopping 90 percent. It takes a well-trained chef to appreciate the real value of a Sakai knife, and for those who do, loyalty runs deep. Made painstakingly by hand one at a time, Sakai knives are a Traditional Craft Product recognized by the Ministry of Economy, Trade and Industry. It is a group effort to make a Sakai knife. Small shops, each variously handing the steps of forging, edge crafting and hafting, are clustered in one section of the city. And like the metalworking practices that spread from the Asian continent, the history behind the development of those skills traces back to another migration event: Portuguese expansion in the Pacific.
In the middle of the 16th century, the Portuguese introduced matchlock muskets to the island of Tanegashima off the southern coast of Kyushu. Sakai merchants carried those manufacturing techniques to their home city, and large-scale musket production soon ensued. Already well versed in techniques of foundry and smithing, Sakai’s artisans were able to replicate the barrel and firing mechanisms readily. It was the height of the Warring States period. As daimyo continued to wage battles to expand their power and fiefdoms, Sakai emerged as the largest manufacturing base for muskets, not only in Japan but in the world, producing some 100,000 of them until peace was established in the Edo period (1603–1867).
In the latter part of the 16th century, Sakai artisans began to make cutters for tobacco leaves that were superior in quality to imported ones. The government issued them exclusive rights to trade these in the 17th century, after which Sakai tobacco cutters spread rapidly to other parts of Japan. Some decades later, manufacture of the deba knife launched the production of many different types of kitchen knives in Sakai. There’s a lot of history in a Sakai blade today—a culmination of know-how that can be traced back to metalworking customs carried over from mainland China, and skills subsequently honed through the study and manufacture of products from both home and abroad.
Structurally speaking, the beveled edge of a kataba knife is more acute than that of a double-ground blade, and cuts only to one side (to the right if the knife is made for right-handed use). Its backside (to the left of the handle of a right-handed blade) is fashioned to have an ever so slightly concave curve, known as urasuki. This minimizes contact, and thus friction, with the surface that is to be cut—thereby resulting in less bruising, crushing, and moisture loss from the tissue. These features are why Japan’s single-edged kataba knives offer far more performance value than just cutting food.
Single-edged knives slice cleanly, rendering cuts with a smooth, glossy surface and sharp, well-defined edges. That beauty is an important visual aspect of Japanese cuisine. The smooth surface of each slice is proof that the delicate tissue structure of the flesh remains intact. This translates directly to a more appealing mouthfeel and texture, and the flavors remain unsullied.
With the exception of honyaki knives forged from a single material (typically high-carbon steel), most blades in Japan are shaped by hammering hagane hard steel for the cutting edge together with softer jigane iron. Hard steel enables a razor-sharp blade, but tends to chip and break easily. This is why knife makers developed the awasemono style, combining a sharp steel blade together with more resilient, softer iron that better withstands impacts. This dual structure makes the knives both strong and easy to sharpen.
Japanese knives are hand-forged and crafted one at a time by master artisans wielding the elemental forces of fire and water. The process entails more than 20 labor-intensive steps, from forging to edge crafting, handle making, and assembly. To make a Japanese knife worthy of its name means not even the slightest mistake can be allowed at any step along the way. What’s even more alluring is that these techniques and knowhow have been passed on and further honed by craftsmen across the generations, in their ongoing quest to create the ultimate precision cutting tool. Deftly transforming lumps of steel and iron into exquisite objects of beauty, these artisans have given us knives that are now sought the world over.
White steel is the pure form of carbon, making it the closest material to tamahagane steel, which was originally used to craft Japanese swords. Forging a knife using only white steel is extremely difficult and very few highly skilled craftsmen are still able to forge kitchen knives with this material. This makes knives made out of purest form of white steel exceedly rare. Using a knife forged out of white steel also requires great skill, as these knives are brittle and more difficult to maintain due to how reactive they are to acid and moisture. However knives forged out of this material will have the sharpest edge achievable.
Blue steel is a mixture of chromium, tungsten, and white steel. The addition of chromium and tungsten to white steel gives it added hardness. Knives forged out of blue steel have become increasingly popular, because this steel is a good compromise for those who want a carbon knife with a longer edge retention. More detail : Elements of Steels
“I make the flux powder by mixing boric acid, borax, and iron oxide,” master blacksmith Ikeda explains. “It’s not an adhesive, by the way—when the two metals are heated to about 1,000 degrees Celsius, the powder combines with oxides and other impurities on the welding surface before flowing out of the joint. That way, it helps to make a stronger weld.” Known as forge welding, this method utilizes the dual forces of heat and pressure. As Ikeda repeatedly heats and hammers the metals together, sparks of iron oxide fly in all directions. All the while as he hammers, he is shaping the desired form. When the two metals are completely joined, he covers the welded piece with straw, which immediately flares into flames. In so doing, he is helping the blade to cool at a desired rate. “The burning straw slows down the cooling process, and so prevents the blade from hardening too fast. Otherwise, it might crack. Tempering is done later, at the next step of heating and quenching.”
The higher the carbon content of the steel, the longer Ikeda allows for it to cool. Of the different types of steel shown on page 8, white carbon steel #1 requires more time to cool than #2, and #2 more than #3. The delicate blue carbon steel #2 is given still more time to cool than white carbon #1. “With its high chromium and tungsten content, blue steel does not wear out easily. Many chefs will swear that blue steel is ‘hard,’ but actually white steel #2 and blue steel #2 are not so very different in hardness. It’s more accurate to say that blue steel’s makeup is such that it slides more readily.” While blue-steel knives cut smoothly through ingredients without catching, they are very difficult to sharpen. Nevertheless, once properly sharpened that edge lasts long, as it has high resistance to wear. These considerations, and more, go into the welding process. If not allowed to cool slowly enough, the two metals will not join properly. The imperfect weld then shows up on the blade, such as in a discoloration, when its edge is being formed. The flaw may be so slight as to be indiscernible to any but the most experienced eye of a polisher, but still the knife will not be fit for sale. All of this is why the cooling step demands the utmost concentration. Once the cooled blade is shaped into a desired form by further grinding, hammering, and trimming of burrs from its edges, it begins to look like a proper knife. Now the forging process moves to its red-hot quenching climax.
In the quenching process, the knife is reheated to 780 to 800 degrees Celsius and then plunged in water to cool rapidly. This step effectively gives the steel its cutting edge. Before heating, Ikeda first coats the blade with clay and lets it dry. “The coat of clay is applied to suppress water vaporization on the knife surface, and thus quicken the speed of cooling. Without the clay coating, the surface would form iron-oxide layers, impeding the progress of hardening. Artisans of olden days must have discovered the use of clay by trial and error. Swordsmiths in the 12th century probably used the same method,” Ikeda explains. When placed in the center of the furnace, the knife gradually takes on reddish tints. Ikeda keeps the room dark so he can clearly see subtle changes in the knife’s color. When it gets to just the right hue, he removes it from the fire. He uses no thermometer. “When the knife becomes the color of sunset, it’s time to take it out,” he says matter-of-factly. “More precisely, a sunset at the moment just before the sun sinks beneath the horizon. People used to call this the color of ripe persimmons. As its color begins to approximate that of the setting sun, the red-hot knife looks more and more majestic—like a torch silhouetted against a darkened sky. The transformation happening in the deep recess of the furnace seems like a sacred ritual, some mystical and very ancient rite of passage. Ikeda pulls out the knife and plunges it into a water bath. A mist of vapor rises with a hiss. What alchemic change occurs in the steel when it is cooled so rapidly? Austenite, a nonmagnetic allotrope of carbon and iron found in steel heated to high temperature, transforms into martensite, a steel crystalline structure. This, in chemical terms, is what hardens the material. As it is still too brittle at this stage, the knife must undergo further tempering by means of another heat treatment. It depends on the item, but Ikeda typically reheats knives to 170 to 180 degrees Celsius in an electric oven for 30 minutes to an hour. Taking out the tempered knife, he lightly hammers out slight warps caused by the heat. With these adjustments done, the knife is now ready to leave Ikeda’s hands and undergo the next process.
“You can tell a lot about a chef just by the knives he’ll send in for repair. You can even tell how good his cooking is,” asserts Shinpei Ino, a certified traditional craftsman and a Sakai polisher with a loyal following of patrons and fellow artisans. When a nascent knife arrives at Ino’s workshop from the smithy, his work begins with rough grinding to craft an edge. This involves grinding the jigane soft iron on the front side of the knife to expose the steel underneath, which is welded to the back. “At this stage I pay special attention to the shinogi [the ridge between the flat and cutting edge], to thickness, and to the angle of the blade,” he says. The grinding wheel sings fiercely as Ino sets the knife to it. In almost no time at all, a cutting edge emerges. To Ino’s knowing eyes, the smith’s workmanship and idiosyncrasies are revealed, too. “If a smith were to turn in poor work, no amount of skilled polishing could remedy it,” Ito explains. But as a matter of course he does make a certain degree of adjustments in the act of polishing. With the knife roughly shaped, Ino holds it up to the light to spot small pits or other distortions, then hammers them out. Years of experience lie behind the keen eyes and seasoned hands that tell him exactly where to beat and how much force to apply. Using a tool called kojibo to correct the largest warps, he gradually brings the knife closer to its ideal form. As he polishes the backside, making the blade thinner and sharper, a rough-looking knife appears. Ino next polishes the tool on a buff wheel, a rotary sharpener coated with an abrasive emery powder. “Its surface is like sandpaper,” he says. He crafts a slightly different shape that hones and keeps the edge sharp for longer. As sparks fly, the knife takes on the fine luster of a razor-sharp blade, but Ino’s work is not completed yet. He next works the blade on a wooden wheel to give its spine, face, and backside an elegant matte finish. “It’s a final touch, toning down the glossiness and honing the blade one last time,” he says.
Hafting is the last process the blade must undergo to function as a cutting tool. A skilled artisan makes minute adjustments to determine the best angle at which to insert the blade into its handle. One of the characteristics of Japanese knives is the way the blade is affixed to the handle. A Western knife is secured to its handle by the use of rivets, while a Japanese one is fitted via the nakago, the sticklike shank that extends from the blade. It is also known as a tang. “If you force the tang into the handle, the handle will crack. First, you heat the tang of another knife and insert it into the handle to enlarge the hollow,” explains Aoki, the owner of Knife System. He takes the knife to be hafted and drives its tang firmly into the heated handle.
When the handle cools, there is no way of pulling the knife out again. Despite the ultimate simplicity of the structure, once fitted securely in place, the knife will not budge. Choosing a handle for your knife adds pleasure to your purchase.
Korin’s Original Knife Guards are the most affordable way to protect your knives. Each piece is lined with a soft fabric to avoid scratching the knife. These durable plastic guards are available in four different convenient sizes for different styles of knives to protect newly sharpened blades.
There is a common misconception that honing steels sharpen knives. Although honing steels straighten out the edge, which will make the knife seem sharper, they do not sharpen the knife. Improper usage of honing steels may even result in chipping and leveling out the asymmetrical 70:30 blade.
Sharpening stones must be used in order to sharpen a knife to its fullest potential. The process of sharpening on a stone is similar to sanding wood. The whetstone scratches away material to shape and polish the edge to an acute blade. A medium and fine grit stone are both needed to effectively sharpen both traditional Japanese and Western style knives.
Take care and protect your investments with our easy- to-use knife accessories. Our knife care accessories were created to keep your knives in pristine condition while our knife storage accessories were created to make sure that your knives last a long time. From our Tsubaki Oil used to prevent rust on your high carbon steel blades to our Wooden Saya Covers that are hand-made to protect your blades, Korin has a full range of products to care for your knives.
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