How Japanese Knives Are Made

Simply put, the manufacturing process greatly impacts a knife's performance. This absolutely cannot be understated.

Let's first look at what determines this on a more general level. The two middle columns, Heat Treatment/Forging and Edge Sharpening are the key components of the manufacturing process. As the below demonstrates, while these processes have very strong impacts on the knife's kireaji or feeling of sharpness, they also impact a knife's balance and maintainability. Unlike the other categories in the table below, they impact the entire end result of a knife.

Let's compare by framing it with a relevant example.

When it comes to cooking, a delicious dish comes together when the ingredients, preparation, cooking processes, and seasoning are all in place. If you cut corners in any of these steps, while the result can still be called "cooking food," it may not taste as good, or you may get tired of the taste.

The same is true in the world of kitchen knives. A good kitchen knife can only be made when the right steel materials, heat treatment, forging, edge sharpening, and handle attachment processes are all there and they are done correctly. A knife is still a knife even if corners were cut in manufacturing. Yet, the resulting knife may not be as sharp or hold its sharpness as long, may be more difficult or even impossible to sharpen, or may have less of a general lifespan.

If all the steps are there and done well, you can make something great!

If a knife is cheaper, it's likely had cost-cutting implemented.

If we think along the lines of our examples above, we can't be too particular about items like kireaji, balance, and maintainability if cost issues become a factor. A good knife generally takes more money and time to make, due to material costs, the blacksmith's expertise, forging times, and various availabilities among other factors.

It's also difficult for an untrained eye to see if a knife's quality has been impacted just by looking at it. It gets even harder when you factor in the secrets that can be employed to make a knife "cheap yet high quality." Let's take a look at some of the methods you may see used.

1. The knife "isn't meant to be sharpened"

Sometimes you might hear about a knife claiming it never needs to be sharpened. This is always a bit of a risky statement from a marketing perspective.

It's nice to hear stories about overcoming problems through technological innovation. We pursue the same in traditional knife culture. The more advancements we make, the better knives become, unlocking better potential.

However, knives are primitive tools - they've been used for millions of years! Plus there are the contradictory pursuits of making knives both thinner and harder; it's difficult to accomplish one without sacrificing the other. If you hear someone say that the problem of needing to sharpen has been "solved," you should probably be a little apprehensive. There's a high chance that the knife, to acquire the ability to "not need to be sharpened" has had a sacrifice made elsewhere.

For example, ceramic knives, which some people claim never need sharpening (which is untrue) are extremely brittle, and will chip at so much as the sight of bones and frozen food. Plus, as our article about what makes a good knife explains, they take getting used to because of a different center of gravity.

Knives are meant to be sharpened, especially higher-end ones like carbon steel and premium stainless steel knives.

2. The knife has a special coating

A special kind of "coating" is often advertised on knives in the 10,000 to 20,000 yen range. Of course, anything "special" sounds attractive and can be good marketing! A lot of yen goes into making sure knives are marketed well and reach a larger audience.

If a knife's packaging says that the coating is the secret to a knife's sharpness or durability though, be careful. These knives either can't be sharpened for various reasons, or the coating peels off if you do sharpen them. It is a similar concept to some Damascus knives; if you sharpen them incorrectly, the patterns can vanish.

You might also hear people say "It's fine if you use a special water sharpener (also called a roll or pull sharpener)." Most of these sharpeners can only sharpen at one angle and only work on thin edges. For a brand new knife that has a thin cutting edge, these might keep your knife sharp for a while. But, as knives have a tapered shape, its thin edge will be shaved away as you sharpen the knife over time. The knife's cutting edge thickens, and cutting into ingredients becomes very difficult. This thick edge needs to be given a tighter angle and made thin once more. Most water sharpeners can't recreate that thin angle, making them significantly less useful on knives that are not brand new.

The picture below is an example of this. This is why we always recommend using whetstones, either artificial or natural (but stick with artificial if you're new, read more here!)

3. Mass production that prioritises manufacturing efficiency

When a company orders larger amounts of a specific high-quality material, we've seen they tend to focus more on the following:

1. The knife's final appearance (so it's attractive to consumers)
2. The ratio of automatic sharpeners to manual sharpening used during the sharpening processing (as this reduces labor costs)
3. A generally lower hardness level in the knife (as this makes the knife easier to forge)
4. Leaving the material thick and making the sharpness appear just at the edge (as this reduces labor costs and expertise needed)

When a knife is made like this, it can be advertised as "using high-quality materials" - as it's doing just that! Due to the above, each unit will have a lower cost price, and it's easier for retailers to sell who can hold that inventory en masse. A VG10 stainless steel knife made by hand from a master blacksmith and sharpener and a VG10 knife made with a machine and pressed out are still both VG10 knives. Comparisons must be based on more than just the steel used.

More expensive knives will be significantly different. They are harder and thinner, which gives them a sharper edge than mass-manufactured items. If the processing on these is not done carefully, the knives can crack or chip during production. This means further waste both in materials and time spent, increasing costs. The production and labor costs are more expensive too as high-quality knives such as Sakai hand-forged knives require master artisans to work and inspect, and it's not possible to make a lot of them by hand as it simply takes more time to do; it's a process that much like many other traditional Japanese crafts can't be scaled up. Generally, multiple people are also involved in high-end knife manufacturing processes, as certain artisans are responsible for certain steps. The person who forges the steel is probably not the same person that attaches the handle.

Until a few decades ago, knives didn't exist that could cut ingredients for a price like a few hundred yen or a few dollars. Knives suitable for display cost more than the few thousand yen or fifty dollars they can now. In that sense, technological innovation is wonderful. It's made entry-level knives more accessible to everyone, and from the lens of spreading foodways cultures that is a good thing.

However, let's also look at it from the perspective of loving a knife for a long time and having a lifelong tool that can be a partner for your culinary journey. It's important to consider whether a knife can be sharpened and what will happen to it when you do.

In short, always consider the tool's potential longevity when you buy it. A 300 yen knife you might throw away, but a 30,000 yen knife you can keep for a lifetime with proper care, let alone knives that cost more. Plus they will likely perform better in general too.

Additional Information: Do knives that don't need sharpening actually exist?

As we wrote earlier, there are many knives out there that claim to "not need sharpening". You can interpret this more as no matter how many times you cut something hard, the knife will stay sharp. This implies that the knife itself has incredibly high hardness levels. Yet, this also means that a whetstone won't work on a knife that is that hard. It makes us curious as to precisely what was used to carve through the material to make the knife shape in the first place...

A good example of this is ceramic knives. They are incredibly hard, but also very difficult to sharpen due to that hardness; it's possible, but far from easy.

Also, such a knife would get stuck in a cutting board incredibly easily. It isn't impossible to make a high carbon or stainless steel knife like this—If you used Blue Steel Super or ZDP-189 steels with a very particular sharpening and tempering process you can make a knife that cuts that way. We have made such knives in cooperation with our craftspeople on request from some customers. But, we personally think these knives are incredibly difficult to use as they get stuck constantly. Additionally, they are incredibly expensive to make and don't fully function as a tool as we see it, so we've not accepted a request like that in many years.

Of course, you can make the cutting board harder by using a heavier or more dense wood, but then the blade will lose sharpness faster when it hits the harder board, so the blade needs to be harder... And it's an endless cycle from there.

With currently technology at least, it's simply not possible to make a knife that never needs sharpening for anything in the tens of thousands of yen (hundreds of dollars) price range, let alone only thousands of yen (tens of dollars.) We will see however where technology and time takes us.

In short, even if a knife is made with high-quality materials, if processing steps have been skipped or sacrificed in order to cut costs, the true potential of those materials cannot be realised. In the worst case, the knife may not be sharpenable at all or it may deform after sharpening - resulting in a knife that can no longer cut. Furthermore, these knives tend to have thicker cutting edges. While they are more chip-resistant, they also dull faster.

Single-edged Japanese knives are a mainstay of traditional Japanese cuisine. Many steps are involved in forging a traditional knife by hand - we have a video just below showing our 41-step process. The key steps of hardening and sharpening the blade are difficult to do correctly, requiring a master's keen eye and skill. By understanding and showing the manufacturing process, we think people will also gain a deeper understanding of their tools and be able to bring out the best in them.

Watch along below and learn what you can! This video is only in Japanese, but the footage shows most of what you need to know. If you have questions or comments, contact us and we can answer further.

Double-edged knives are used around the world in modern cuisine. In Japan, many households own Japanese double-edged knives like santoku, gyuto, petty, and nakiri knives; often the first knives someone will purchase for their home. Knives with a Western-style handle require different steps to create and attach the handle and clasp. Our SWORD-FV10 series is a perfect example of this, using unique heat treatment steps and extra rounding steps to make the best Western-style handle possible.

The manufacturing process is still almost completely done by hand, with the assistance of a machine press at the very start. Forging these knives still needs expert work for the sharpening, treatment, tempering, and quenching stages. This is all done by hand, with a keen eye. For high-end knives, these steps cannot be replicated by machine.

It's a common misconception that knives with a Western-style handle are mass-manufactured in factories completely by machine. We hope our video here shows you otherwise.

Watch our process for making a SWORD-FV10 knife from start to finish via the video below! This video has English audio and subtitles, but a Japanese version is also available. Contact us for a link!