The complicated process behind making Japanese knives

If you walk into most knife or kitchenware stores, you're likely to encounter two broad groups: Western knives, rooted in German and French cutlery traditions, and Japanese knives, some of which date back hundreds of years to the samurai and their notoriously sharp swords. .

The difference between Japanese and Western knives

Traditional Japanese knives come in a wide variety of shapes and sizes, designed for specific tasks such as cutting fish and slicing vegetables, noodles, sashimi, eel or blowfish… if you want to cut blowfish. These knives have historically had a single bevel blade, meaning they are beveled on one side only, so they are either right-handed or left-handed (usually right-handed, which is unfortunate for a lefty like me). These blades are then tapered into a thread hammered into a wooden handle.

Western knives, on the other hand, have shapes that most home cooks in the United States are likely familiar with (cutting knives, chef's knives, bread knivesetc.), and have a two-handed design: the blade is symmetrically sharpened on both sides, so it has a double beveled edge. The handles of classic Western knives are also typically made of two pieces of wood or composite material, which are used to sandwich the tangs and then fastened with rivets.

Another characteristic that distinguishes Japanese knives from Western knives is the hardness of the steel they use. The steel of Japanese knives is on average harder than that of Western ones, which makes the knives more fragile, but if handled with care, they can keep their edge longer. The milder steels used in many Western knives are less brittle, allowing their micro-thin blade edges to roll to one side or the other before breaking; rolled edge can be restored a honing rodwhich does not work well with the more brittle, harder steel of the Japanese knife. When the time comes to repair a Japanese blade, you'll need it a grindstone.

The hardness of the metal is expressed as a number Rockwell scalewhich measures how much pressure is required to drive an indentation into a material and is usually expressed as an HRC number for steel knives. Japanese knives often have an HRC rating in the low 60s, while many western knives have slightly softer steel and fall into the 50s.

However, these distinctions only go so far, as many Japanese knife makers go beyond traditional Japanese styles and sell a wide range of hybrid knives that combine Japanese and Western characteristics – santoku and gyuto knives are relatively common examples. In some cases, Japanese companies release knives that have much more in common with their Western counterparts than with traditional Japanese ones. At the end of the day, what sets a Japanese knife apart from Western knives is that Japanese knives are made in Japan.

How Japanese knives are made

But who makes these knives and what is the process like? There are several cities in Japan that are famous for their knives, including Sakai (near Kyoto), Seki (in Gifu Prefecture), and Echizen (in Fukui Prefecture). To see the process firsthand, I visited a Japanese knife factory in Echizen last year. Or rather, I visited eight Japanese knife factories. This is because I was at Takefu Knife Village, a consortium of knife makers who all work in the same facility.

Each of the eight knife makers operates an independent business—they are technically competitors—but they share a location and some equipment, and they market their wares both independently and as a group. Plus they all seem to be friends. It's rare, if not unheard of, to find competing businesses sharing space and resources in the United States, but Echizen's knifemakers have been at it for centuries.

According to the city's history of knife making on the Takefu Knife Village websitedates back to the 19th century, when a famous blacksmith from Kyoto visited the area in search of quality water to quench his steel. While there, he made swords, tools and knives for the locals, while teaching his trade.

For centuries, Echizen was most famous for its agricultural implements and at one point was Japan's leading source of sickles. Although they still make farm implements as well as scissors, production has largely shifted to kitchen knives. Today, while each manufacturer sells knives under its own name, the collective also takes knife orders from larger companies, which add their own branding to the product before putting it on the market.

Each Takefu knife factory has its own house style, defined by the factory's master knife maker. The masters, along with their teams of junior knifemakers, produce their line of knives from their own preferred materials and designs, but the knives are all forged from rough blocks of steel, called blanks (as opposed to being stamped from sheet metal). , which is another common knife-making method). All manufacturers buy their steel from the same Takefu-based steel company, but the exact metal chosen depends on what they are making; one of their favorites is Super Gold 2 (or SG-2), a type of powdered steel. The knife making process owned by Yoshimi Kato Kanehiro knivesit goes roughly like this:

Forging the Blade

A knifemaker starts with pieces of metal, heats them up in the forge, hits them with a heavy hammer—a large, spring-loaded rig—to shape them, and then quenches them in cold water to strengthen the metal. As this cycle repeats itself, the metal gradually begins to take on the shape of the blade and the unique properties that a good kitchen knife needs. Their goal, in the simplest sense, is to create blades that are consistent in hardness throughout and free of fatal flaws that can lead to problems down the road. In some cases, the knifemaker will forge different layers of metal together to combine their relative strengths and balance out their weaknesses, creating cladding layers that sometimes appear as beautiful ripples on the blade.

Mr. Kato said he often works with batches of 10 to 30 blades at a time, rotating them over a three-day period during the entire process.

To keep the blades nice and straight when they are forged, sometimes two are struck at once, each blade acting as a kind of brace for the other – the thinner they are, the more useful they are.

After the forging process is complete, the knives are sent to the sanding belt, where the rough edges are cleaned.

This is especially important for knives with Western-style handles, where the tang is sandwiched between two pieces of wood (or wood-like composite material). If the gouge is not perfectly smooth and level, there will be gaps in the handle, allowing water to penetrate and corrode it.

Burning the knives

On the second day, the knives are put into the oven to be fired. Heating the knives to a high temperature and then putting them through a carefully calibrated cooling process helps control the metal's hardness by rearranging the metal's molecular structure. But since there is still work to be done, the metal has not yet reached its final hardness level at this point.

Burnished blades can be polished for a glossy finish or left more or less as is for a more rustic matte look. At this point, another machine is used to cut the blade, finalizing its exact shape.

Finishing the knives

On the third day, the still-rough-shaped blades are hand-hammered even more, but this time without the heat of the forge—the metal, having already been fired, is on its way to its final hardness characteristics and would be discarded when placed back into the forge's heating and cooling cycle.

After the final firing, in which the blades are again heated to high heat and then immediately cooled in water, the final hardness of the metal is set.

With the knives burnished, polished and shaped, the final step is to sharpen the blades and attach the handles.

Of course, sharpening is not a small matter, and in the Takefu knife factories there are two wheels each, which are handled by specialists in order to put a smooth edge on the blades. As the wheels rotate at high speed, spray with cold water so that the friction does not raise the temperature of the metal; The knife must be kept cool after firing so that its quality does not deteriorate.

After my tour of the Takefu knife factory, Kato led me over to another building on the site, where one of the knife makers, Yu Kurosakimakes his knives. He's the only member of Takefu Knife Village who doesn't work in the main building, after his reputation grew he moved into his own – at the time of my visit he said he was working on 3000 orders…quite a waiting list.

Kurosaki aims to make his knives as light and thin as possible. Blades of various finishes sat on sandpits cut into the concrete floor, in boxes and tubs of anti-rust liquid.

In one of the boxes I spotted a special metal stamp used to make decorative markings on the blades.

His knives are arguably the most internationally famous from the Takefu Knife Village, but other manufacturers also make excellent blades. The only website I have been able to find that has knives from all of Takefu's knife manufacturers is Chef knives. I've been using a couple of their knives since my visit – two santoku with traditional Japanese wooden handles but with a more western blade geometry – and they're definitely worth checking out.

July 2018