An Advanced Beginner’s Guide to Japanese Kitchen Knives
Kantapat (Gunn) Jungpaibul - October 2023
Part I: Introduction and Motivation
Ever since a young age, I have been fascinated by knives. My dad has a collection of traditional Thai krabi (swords) and knives of all different types, ranging from the functional to the older art pieces. I never thought much about them, apart from the fact that these traditional Thai swords are meant to be dual-wielded, which I thought was awesome. Many historical Thai movies also incorporate Muay Boran, the original form of Muay Thai, alongside with Krabi-krabong, the ancient weapons-based martial art of Thailand which uses these swords. The usage of swords and knives is cool, but I never learned much about the design of these tools and weapons, even though I always admired the intricate woodwork and the way the metal glints in the light. That admiration definitely carried over to when I grew older and got introduced to Japanese knives, starting from a fateful encounter in orchestra class.
Well Amatavisuit was a senior in high school when I was a sophomore, and he played the viola. As a cellist, I always sat next to the viola section, which made it super easy to goof off with him. One day our conversation led us to knives, and Well revealed he was a knifemaker. Naturally I was interested, so I half-jokingly asked if I could be his apprentice. He said sure, and the rest is history.
The first day at his workshop (his backyard) was mostly me asking questions. I had no idea what I was getting into or what kind of knives he made, but then he showed me the folding knife that he was currently working on. I was amazed. It had a beautiful shape, with a blade of Damascus steel. After much prodding, Well revealed that he was Thailand’s youngest knifemaker, and the waiting list to order one of his creations is a few years long! His specialty is custom folding knives, and each one sells for a lot of money.
Well showed me around his workshop, explained what each machine did, showed me pictures of his past creations, his steel collection, and most importantly for this paper, his small collection of Japanese kitchen knives and whetstones. Well explained that he started off on a whim, armed with the knowledge of English and YouTube. He bought a 20 dollar metal grinder, and began fashioning a junk railroad spike into a knife. He made camping knives and other fixed-blade knives, slowly expanding his workshop. One day, he met Uncle Tim, who had been making knives for over 30 years, at a church. With Uncle Tim as his sensei, Well honed his skills and craft and slowly became known in the Thai knifemaking community.
At the end of the first day, I agreed to work with him for the whole summer; I would help him with his production, and in return he would teach me all that he knew, and he would guide me to create a few knives of my own as well. I spent two summers and one winter in his workshop before I had to go to Wesleyan, culminating in one small fixed-blade utility knife, one gyuto, and one folding knife.
In this paper, I have two main goals. As I’ve never formally written about my experience or process before, my first goal is to write a reflective essay on my learning journey and what I’ve done. My second goal is to write a Japanese kitchen knife guide for the advanced beginner. There are many great guides out there for a complete novice, however, once someone has gained some experience and is looking for the next step up, they find the information online is quite overwhelming. Too often I read articles and websites online that are just plain wrong or misleading. Research papers are a great resource, but they’re often too specific and filled with jargon. Books are excellent as well, but they tend to focus on either blacksmithing or techniques and recipes. What does an advanced beginner do when they’ve just becoming more discerning and they’re looking for a new knife? They flock to knifemaking forums, where good, informative posts are few and far between and are nestled deep in the reply chain.
I would like to use the knifemaking process, chronologically, from drawing on a piece of paper to the final product, to explain Japanese kitchen knives. For example, as I talk about how a knifemaker decides on a shape and length of a knife, I will introduce different knives such as the yanagiba or the usuba, just as my sensei taught me all those years ago. As I explain forging, I will introduce kasumi knives and honyaki knives, and so on and so forth. Through this process, I learned a lot. I hope you do as well.
Part II: The Making of a Knife
Section 1: Purpose, and Japanese vs. Western
A few weeks into the summer, I’ve become familiar with the equipment and machinery in the workshop. I’ve helped my sensei do a whole bunch of different things, and I’ve made my first knife — a small utility knife. Normally I would have to make a lot more smaller fixed-blade knives before progressing to culinary knives, but I guess Well saw my love of cooking and wanted me to have a chef’s knife of my own.
At this point, I was faced with the daunting decision of what type of knife to make. Well began by handing me a whole bunch of papers with knife outlines on them. He also brought multiple knives from the kitchen to show me. The knives and outlines in front of me included western styled chef knives, Japanese styled chef knives, Chinese cleavers, and Thai styled kitchen knives. I had a bunch of Thai knives and a Chinese cleaver at home, so the question was Japanese vs. Western.
The difference between these two schools of thought, summed up in one word, is purpose. Western chef knives are multipurpose workhorses, designed to slice onions and to dodge chicken bones. For Japanese chef knives, a vegetable cutting knife is distinct in both shape and form from a knife that goes anywhere near bones. From that, one can infer that western knives require a softer, tougher edge that won’t crack or chip when it inevitably comes in contact with bone. Therefore, with this specialization, Japanese knives can be harder – and keener. There is variety in the Western knife world, but usually only in size and length, nothing compared to the hundreds of different knife shapes and thicknesses in Japan (Abe, 2011). To illustrate this, there are four different types of unagisaki, or eel knives, each coming from a different region, and their shapes are completely different! Using the Kanto and Kansai unagisaki as an example, there are different types of eel and different eel preparation techniques that create a need for a different blade shape (Korin). Apart from specialization, Japanese chefs also prepare ingredients differently from Western chefs because of Japanese emphasis on presentation and subtle flavoring.
A knife can affect an ingredient’s flavor and aesthetics. Picture a tomato, sliced with a dull knife. The knife does not immediately pierce the tomato’s skin as it is not sharp enough. The knife will have to crush the skin with brute force until it gives, juices will burst out, and the edges of the tomato will be ragged from the sawing. A sharp knife will cut through the fiber in a single, clean stroke, leaving a shiny and smooth surface, without any juice on the cutting board. A cleanly cut tomato will look more appetizing, taste better as all the juice is intact, and will have a better texture from the completely uncrushed flesh. An unclean cut on an onion will tear the cell walls, release enzymes that oxidize and change the flavor of the ingredient. A similar effect is in play for sashimi, where a longer sharp knife is needed to beautifully slice the fish in one smooth motion, leaving a sharp edge and a glossy surface. As Nozaki mentions, there is a strong aesthetic tradition in Japan that “links of the appearance of food to good flavor” (Nozaki, 2012).
Nozaki continues that “the knife is truly the foundation of Japanese cuisine, and the act of cutting is essential” (Nozaki, 2012). He espouses the belief that “to cut” is actually “to cook”. Rath furthers this in stating that around the 15th century, the Japanese word for chef is hōchōnin, which literally translates to “men of the carving knife” (Rath, 2010). This shows how important the knife is to the profession. Even back then, elites and aristocrats had “knife ceremonies”, called shikibocho or hochoshiki, where the hochonin carved a large fish or game bird into a “visual display similar to a flower arrangement” (Rath, 2010). Nowadays, chefs are called itamae, literally, “in front of the cutting board,” to a similar effect. It takes years for an apprentice cook to become a wakiita (near the cutting board), and up to 20 years total to become a fully-fledged itamae (Lowry, 2005). This requirement of precision is evident and embedded into the cuisine.
Accordingly, techniques of knifework used by Western and Japanese chefs also differ. Rock chopping, where the chef places a hand or finger down near the tip of the blade and chops by moving the handle up and down, is not a technique used by Japanese chefs. French and German chefs use this method, and their knives are characterized by the pronounced upwards-sloping belly. Traditional Japanese knives have a flatter belly, related to the main categories of push cutting and pull cutting.
I wanted to have a knife that “dropped through carrots like a hot edge through ice cream” (Donald, 2018), so the choice was clear – I had to make a Japanese knife.
Section 2: Blade Shape, Thickness, and Length
After deciding to make a Japanese chef’s knife, which one? There are hundreds, after all. There are two main types of Japanese knives: single-beveled and double-beveled. To begin, we must examine the advantages and disadvantages of single-beveled knives.
As seen in the diagram, a double-beveled blade with an 8 degree angle grind on each side has an inclusive angle of 18 degrees, while the single-beveled blade has 8 degrees total. Does a more acutely angled blade cut better? Yes, it does, thanks to the math done by Trent Hyer.
The top equation shows how the lateral force, or the force pointing perpendicular away from the center of the knife, is related to the angle of the point, in degrees. A larger angle, shown on the right in red, leads to a lower overall lateral force and thus requires more downward force generated by the arm to have a similar cutting ability to the smaller angle. However, one must be careful not to confuse spine thickness with edge thickness. Two knives with equally thick spines, but the one ground down to a finer, more acute angle at the edge will cut better. This conclusion proves an overarching point #1: a thin knife cuts better than a thick knife (Hyer).
Consequently, in most cases, a single-beveled blade will cut better, smoother, and with less effort than a double-beveled blade. This is also a comparison that can be made with Western styled blades. Single-beveled Japanese blades are commonly found with inclusive angles ranging from 10 to 15 degrees. For double-beveled Japanese blades, the inclusive angle is usually around 20 to 30 degrees. In contrast, German or French styled blades usually have angles around 34 to 50 degrees. Because of that extra thickness, Western knives are tougher than their Japanese counterparts, but they sacrifice cuttability. There are disadvantages to single-beveled knives too, namely they’re harder to use and harder to sharpen.
The three main single-beveled knives are the deba, usuba, and the yanagiba. The deba is mainly used for cleaning and filleting fish, as well as dressing poultry and other types of meat (Nozaki, 2012). It has a very thick spine, even thicker than an average Western knife. However, it, and virtually every well-made Japanese knife, has a distal taper. That is, the spine thickness at the base of the knife (near the handle) is thicker than the spine thickness nearer the tip. This design allows the heel of the deba to be used for chopping and cutting through fish spines or chicken cartilage, while the center to the tip can be used for refined filleting work (Donald, 2018). Multiple sizes of deba exist, each corresponding to the size of the fish and bone type. For example, the ai-deba is thinner and lighter than a full-sized hon-deba, and it is used for dressing medium-sized fish with softer bones such as saba (Nozaki, 2012).
The usuba lies in sharp contrast to the deba, even though these two knives can use the exact same steel and steel hardness. The usuba is very thin, literally translating to “thin cutting edge” (Nozaki, 2012). Having a completely flat belly, the usuba is the single-beveled vegetable knife of choice, allowing a chef to peel a daikon into a continuous transparent sheet. This technique, katsuramuki, or the rotary peeling technique, is demonstrated in Abe’s Begin Japanology: Kitchen Knives. The single-beveled usuba can easily keep a flat, consistent sheet of daikon or cucumber, while any other double-beveled blade would fail (2011). Nozaki remarks that the usuba’s development is related directly to the important role of vegetables in Japanese cuisine, forming the traditional diet, especially in the Zen Buddhist shojin ryori vegetarian cuisine. It is important to note that the nakiri, the double-beveled usuba, is very popular in modern Japanese kitchens (2012).
The yanagiba is a long, slender blade, aptly named after the curved willow leaf. Its main job is to slice sashimi, slicing fish in one clean stroke, with the least downward pressure as possible. In other words, it is the knife’s weight that does most of the cutting, allowing the finished cut to be as pristine as possible. As demonstrated in Abe’s Begin Japanology: Kitchen Knives and the figure below, the yanagiba excels at delivering pristine cuts and pushing the fish away from the knife. Not the concaved surface, or urasuki. This extremely subtle concaved surface allows the least amount of the metal to touch the uncut fish, thereby reducing friction and improving food release – a very important factor in knife geometry.
Western influence entered Japan during the Meiji restoration in the 1870s, and among the many dramatic happenings of that period, red meat consumption was encouraged. Western cuisine flooded in, along with the beginnings of yoshoku, and Western knives (Donald, 2018). Enter the gyuto, literally translated as cow-blade. It has a blade profile more reminiscent of Western styled curved bellies but with a thinner and harder blade. Originally designed for cutting beef, the gyuto was in the Western tradition, a multipurpose knife. Gyuto came in both yo (Western) and wa (Japanese) handles. Later on, the santoku appeared on the scene and quickly became popular with home cooks, as it filled a multipurpose role like the gyuto, just smaller and better suited for small kitchens. With the arrival of refrigeration technology, the act of butchering fish whole with a deba in the kitchen slowly disappeared, and along with it the deba (Donald, 2018). Many double-beveled variants of single-beveled knives also appeared on the scene, such as the sujihiki (carving knife similar to the yanagiba), and the honesuki (boning knife similar to the deba).
For my knife, I picked a gyuto. A single-beveled knife would’ve been an odd choice, as I don’t get to cut that many vegetables or make any of my own sashimi. I knew I wasn’t going to deal with any bones with this knife as I have a cleaver at home, so my knife could be thin. It had a distal taper, and I sharpened the edge to around 10 degrees on each side. The shape near the handle was stockier than I would like, which resulted in a gyuto that had a more western feel than I would like. Average blade lengths for professional chefs are around 240 to 270mm, and for home cooks from 180mm to 210mm. I picked 190mm, as it was a nice and snappy length. I later regretted that choice, as I was unable to cut long vegetables like celery length-wise in one swoop.
Section 3: Steel Picking and Lamination
Japan had very poor sources of iron ore, however, the only thing it did have proved to be very unique. Japan had satetsu, which is blackish iron sand found in riverbeds that came from volcanic rock. To extract the iron from the sand, the Japanese developed a clay furnace called the tatara, utilizing very clean-burning charcoal, strategically placed bellows that let oxygen in, and created a carbon enriched atmosphere (Donald, 2018). The result: tamahagane, or “jewel steel”, a hard, high-carbon steel that was easy to work with and easy to sharpen. For that day, tamahagane was very good, but modern steels have it beat.
Hitachi Steels, one of the world’s most productive steelmakers, still uses satetsu to make their fine kitchen-grade steels, with modern furnaces instead of tatara. Japanese knife enthusiasts all around the world know their famous Shirogami “white paper steel” and Aogami ”blue paper steel” (named after the color of paper they came wrapped in), specifically crafted to mimic and improve upon the traditional tamahagane, which is still in production but very rare (Donald, 2018). For my gyuto, I used SK-5 steel, also made by Hitachi Steels. Compared to the godly Shirogami and Aogami, it is utterly worthless, but it gets the job done, especially for a first time Japanese knife maker like me. Note that “worthless” judgement is all relative, stemming only from the very high standing of Shirogami and Aogami; my SK-5 steel outperforms many mass-market knife steels.