The Taste of the Cut
How the best blades are born

Yoneo Mukō’s workshop, accessed by a long straight road that cuts through a patchwork of onion fields, lies on the northeastern shore of Kabeshima, Japan.  Oncoming traffic on this two and a half square kilometer island is as likely to be a slow crawling tractor as a passenger vehicle. Kabeshima’s southern tip is tethered to the mainland via a bridge originating in the town of Yobuko.

On a clear mid-winter morning the sun is bright, the air crisp, and the winds that whip the island with near constancy unusually mild. With an indelibly stiff gait, Mukō shuffles through the doorway of his workshop, the dark interior quickly swallowing his bent 75-year-old frame. Intending to light the coal fired forge, he encourages us to stay outside a few minutes longer. “I’m used to it but initially the fumes are strong,” he says.

Mukō was born into a farming and fishing family on Kabeshima Island. The family possessed only enough land to pass on to his eldest brother leaving Mukō with little choice but to carve his own path in life. At age 15, at his mother’s behest, he entered into an apprenticeship with a blacksmith on the mainland in Yobuko. He studied blacksmithing techniques, growing accomplished at fashioning the tools that his mentor supplied to the regional farmers, fishermen and divers. He learned about customer relations and business operations, receiving and fulfilling orders and securing payment. As he neared 5 years under his mentor’s wing, Mukō came to realize that although his skills were proficient, the local economy could not support two blacksmiths and his prospects for independence appeared dim.

Mukō calls us inside. Long lengths of pure metal lean against the blackened walls. Standing before his forge, he considers the blade he will demonstrate and cuts a length of metal. He sets it into the blazing coals and waits. The forge casts an orange glow onto his face and hands. The workshop is left dim to facilitate an accurate assessment of the blade’s temperature through a reading of its glow.

 

To appreciate Mukō’s craftsmanship requires a basic understanding of hamon, Japanese blades, and washoku, Japanese cuisine. A principal tenent of washoku holds that aesthetics and flavor are inexorably linked. In Japan it is said that to cook is to cut, as expressed by the phrase katsushuhoju (割主烹寿), roughly translating as cut first then simmer. The first treatment an ingredient receives in the kitchen, whether it will be presented raw in decorative form or cooked into a base flavoring, is in the cut of a blade and attention to this first step is imperative.

The ability of the Japanese language to express subtleties of taste is unsurpassed. A multitude of words offer suitable expressions for the varieties of aji, flavor, to hazawari, the feeling of the food against the teeth as you bite and chew. Kireaji, literally translating to sharpness, in its linguistic construction expresses the taste of the cut. As a blade slices, it applies pressure on the fibers of an ingredient. Minimizing this pressure is fundamental to preserving the integrity, aesthetics, and flavor of any ingredient, and Japan, with a long established history of sword making, naturally improved upon forging techniques and knife designs to accomplish just that.

Consider the traditional single-bevel Japanese knife. Whereas a double-bevel blade (imagine the ax) is more suited to chop or split, the single-bevel blade is purposed for slicing. With a pronounced bevel on the front, the back of the knife appears flat, but in fact holds a slight concave curve. Pounded into an imperceptible arch, the blade swiftly and cleanly releases from an ingredient significantly reducing drag.

Operating a belt hammer with a foot switch, Mukō begins shaping the blade, manipulating the glowing bar of metal at the end of a tightly gripped pair of long-handled pliers. Starting at one end, he works the metal under the hammer to elongate and compress it towards a point. Reheating it and moving to the other end he coaxes the last centimeter of metal towards the spine side, stretching it to form the nakago, or tang, a long thin spear to be inserted into a wooden handle. Mukō’s actions reveal his particular mastery. There are many who would fuse the high quality metal of a blade with a lesser quality metal from which to form the tang. Mukō’s blades, tip to tang, are fashioned from a single length of blade quality metal. And though commonly blades are hammered roughly to size and shape and then trimmed to final specifications, Mukō prefers to showcase his skill by finely controlling his movements and hammering his blades into their final form.

Japanese knives are classified into two principle categories based on material; honyaki blades are made of pure hagane, carbon steel, while awase blades combine layers of jigane, soft iron, and hagane. Even for a master blacksmith like Mukō, forging a honyaki blade is a laborious task completed over a span of days. When called upon to demonstrate, he fashions simpler awase blades that can be largely completed in a morning or afternoon.

Moving from the automated belt hammer to a handheld hammer, Mukō raises the expanding blade up for inspection. “Gyuto,” he says. The 10-inch san-mai gyuto, what in the West would be considered a standard chef’s knife, is made of a layer of carbon steel sandwiched between two layers of iron. This style called san-mai is a subset of awase blades suited to double-bevel blades. Over time as knives are subjected to repeated use and sharpening, they lose mass. “The carbon steel core of this blade goes all the way up to the spine,” he says, “so you can use it to the very end.” 

In 1960, nearing his 20th birthday, Mukō left for Sakai, a city outside of Osaka that has been the heart of Japan’s blade making tradition since the 14th century. For 18 years he held a position at Kobayashi Homonten, continuing to forge hand tools for farmers. “I was essentially a salary man,” he said. This likely would have been his life’s work but for a radical change to the face of agriculture in Japan. The 1970s brought a swift shift towards mechanization. A small diesel powered machine could do in a day the work of a dozen farmers. With growing implementation of tractors, paddy planters, and harvesting machines, the demand for farm purposed hand tools plummeted.

Satisfied with the shape of the blade, Mukō seats himself on a low stool in front of his grinding stone. Clasping the metal with bare hands amidst an eruption of sparks, he works the blade against a grinding stone, refining edges and further shaping the blade path. He then takes a hand file and begins finessing the curve at the neck where a cook’s hooked finger would rest.

“It's manual labor,” says his son looking on. “The majority of knives today are mass produced, most stamped out of sheet metal. Even many of the knives sold under the auspices of famous Sakai knives are not necessarily made in Sakai anymore,” he laments. After centuries of refining and perfecting the technique of forging hand made blades, it is in danger of joining an army of dying traditional arts.

Firing up the furnace again, Mukō returns to heating and pounding by hand, confirming the straightness of the blade. “Since I already understood blacksmithing, transitioning to knives wasn’t too hard,” he says, recounting his shift towards knife making. “Actually, making farm tools was more challenging because there is such variation.“ Though his skills afforded a rather swift transition, at first he could only fashion the most basic blades. But Mukō had set his sights on learning to forge a higher class of blade that would challenge his skills and command a better price.

Traditionally forged Japanese blades are the best in the world. And honyaki blades forged of pure carbon steel are the crème de la crème. It takes a master craftsman to successfully fashion a honyaki blade. Anyone with a mind to purchase such a knife is likely a fanatic due to profession or passion and will take interest in the sub-categories of this elite class of blades, including shiro-ko or ao-ko, white or blue steel, and abura-yaki and mizu-yaki, quenching by oil or water.

Nearly 40 years ago, with a mind to make mizu-honyaki, water quenched pure carbon steel blades, Mukō began purchasing his own materials and took every spare moment to practice. But blade after blade, after hours of shaping and pounding, would break as the hot metal hit cool water. Though he had been successfully quenching blades in oil, the rapid cooling that water afforded, the very condition that creates the coveted strong edge of a mizu-yaki blade, caused them to crack time after time.

Mukō can point to the exact day his luck changed, the day a man named Okishiba, a deity-like master blade smith, briefly rented space at Kobayashi Hamonten. Mukō patiently awaited an opportunity to observe him at work. He was finally granted entry, but says, “He wouldn’t teach me anything! I could watch, but he wouldn’t teach me anything.” However the chance to observe proved pivotal to Mukō’s success.

Fashioning a fine blade is the pursuit of hardness as it pertains to strength and flexibility. Increase hardness and though a blade has greater potential for retaining extreme sharpness, flexibility is sacrificed and it becomes brittle. The ideal blade is flexible at the spine but hard at the cutting edge. Ultimately hardness is the result of quenching and tempering. 

Mukō observed Okishiba coating the knife with a stone and clay wash. Acting as insulation, this coating was the key to successful quenching without fracturing the blade. But Okishiba’s lips were sealed when it came to any details on the recipe or application. Mukō would have to figure that out on his own.

Proving that he long ago had, with brush in hand Muko begins painting a stone gray, soupy glaze flecked with grit onto the gyuto blade. Once quenched in water, the edge cools faster than the core and the blade is differentially hardened. While the edge is rendered extremely hard, the spine remains flexible. Demonstrating that he had also learned the lesson of secrecy, he politely clips any further line of questioning regarding the final annealing stage remarking, “I’d rather not say too much.” Like Mukō all those years ago, we could observe but not inquire.

After another interval in the forge, Mukō’s sends the glowing blade immediately into a basin of water. With a sharp hiss a plume of steam is born. In the blink of an eye, the task that Mukō had spent years perfecting is accomplished with hardly any indication of its difficulty. Pulling the blade from the water, it continues to bleed steam. After one more turn in the forge, Mukō’s work is done. 

A traditional Japanese blade requires the attention of several specialists in individual stages of a knife’s production. Once forged, Mukō sends his blades to a wholesaler in Osaka who oversees the production of finished knives. Each blade is sent out to a professional edge crafter who is responsible for grinding the cutting edge, polishing, and sharpening the blade. Back at the wholesaler, each blade is assessed and paired with a professionally crafted handle, then assembled and distributed for retail. It is a tightly controlled industry, each craftsman separated from the others, in communication only with the wholesaler. Despite his accomplishment and some notoriety within the blade making community, Mukō’s blades are essentially sold anonymously, stamped with the retailer’s brand name, not his own.

“In Osaka my hands were tied. I was contracted to sell everything through a wholesaler. There was no way around it." With so many links in the chain, Mukō receives less than 50% of a knife’s retail value. Once he returned to Kabeshima in 1992 and began working at a distance from Osaka, he began crafting his own edges and assembling knives to sell locally. Only these knives are stamped on the blade with his brand name, Gankai Masakuni.

Mizu-honyaki knives are the most prized among professional chefs and enthusiastic collectors. Though they do hold an edge longer than other knives, they require great skill in sharpening, detailed attention to care and maintenance, and a trained hand to use effectively. And though popular among dedicated amateur cooks, a premium knife does not a good cook make. Although Mukō has reached a certain pinnacle, joining the ranks of a very small circle of craftsmen who can and do successfully forge mizu-honyaki blades, he is quick to recommend awase blades. “Jyuubun,” he says, “perfectly adequate.” They make for very fine knives that are more forgiving. And they still offer the superiority of carbon steel at the cutting edge where it matters most. With some concentrated effort and practice, one can learn to sharpen awase blades on good quality wet stones at home. Learning to sharpen knives adds to the pleasure of owning and using good knives on a daily basis, and an accomplished home cook appreciates the flexibility to sharpen her own blades whenever necessary. A honyaki blade, on the other hand, is better sent out to a professional sharpener. And the very nature of honyaki’s increased strength inversely renders them more fragile and prone to chipping if wielded improperly.

Mukō’s son, who serves as an invaluable assistant, can forge standard awase blades but never took it upon himself to learn the craft to its fullest extent. At 75, Mukō will take his knowledge and skills with him when he goes. In the meantime, though his body only allows him to work short days now, for as long as he can, he’ll keep making knives.  

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