Kyomen: Japanese “Mirror” Polished Knife Finish Explained

Author: Joost Nusselder, author of The Essential Japanese meal planner cookbook Updated March 17, 2023

There’s a particular type of Japanese knife finish that is so shiny and reflective you can see yourself in the blade. 

This type of mirror polish finish is called kyomen, Japan’s smoothest and shiniest type of knife finish.

So what is it, and why is it special?

The Japanese mirror polish knife finish, also known as “kyomen” in Japanese, is a traditional method of polishing high-end knives to a mirror-like finish. This process is typically used on single-bevel knives made from high-quality carbon or stainless steel.

In this guide, we’ll explain the mirror polish finish, how it’s made, and the pros and cons, so please keep reading!

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What is the kyomen mirror polish finish?

Mirror finish is a popular look for Japanese knives, but what exactly is it, and how do they get it?

Japanese mirror knife finish is a type of finishing that gives the blade a highly reflective surface. It’s a labor-intensive process that requires a lot of skill and patience.

The final result is a smooth and shiny blade with a reflective surface that resembles a mirror.

The Japanese mirror polish knife finish, also known as “Kyomen” in Japanese, is a traditional and highly skilled technique used in Japan to create a mirror-like finish on the surface of a knife blade.

This technique is used primarily for creating high-end, premium-quality knives.

The process involves several stages of polishing and honing the blade with a series of abrasive materials, including stones, sandpaper, and polishing compounds. 

Each stage of the process involves using a progressively finer abrasive material, with the final stages using extremely fine abrasive compounds to achieve a mirror-like finish.

The result of the Japanese mirror polish knife finish is a blade that has a perfectly smooth and reflective surface with no visible scratches, lines, or imperfections. 

This mirror-like finish not only enhances the blade’s beauty but also improves its functionality by reducing the friction between the blade and the food being cut, resulting in a cleaner, more precise cut.

Many honyaki knives you’ll see have this mirror finish that looks so reflective you can see your face in it. 

What does Kyomen finish look like?

Kyomen knives have a mirror-like finish and are usually highly reflective. The steel is buffed until it has a glassy shine, making it look almost like a mirror.

The finish allows the steel to resist corrosion and staining, making it ideal for use in wetter environments.

The appearance of a kyomen blade is very reflective, and it is often used on higher-end knives.

You can see the reflection of light on its surface, making it a very attractive knife.

It’s usually very smooth to the touch but can be scratched if not cared for properly.

Learn exactly how to take proper care of your precious Japanese knife collection

What does Kyomen mean?

The term kyomen in Japanese translates to “mirror surface,” which refers to how smooth and mirror-like this finish is.

Most people know this finish as a “mirror-finish” due to its high reflectivity. 

How is a Kyomen finish achieved?

You see, Japanese bladesmiths are like the rockstars of the knife-making world. They take their craft seriously and have been perfecting it for centuries.

They use a labor-intensive process to forge traditionally bladed weapons, like the katana, wakizashi, and tantō.

But what sets them apart is their attention to detail, especially when it comes to the finish of the blade. 

The Japanese mirror knife finish is a technique that creates a polished, reflective surface on the blade, making it look like a freakin’ mirror.

It’s like the knife says, “Hey, I’m sharp, AND I look good doing it.”

Now, achieving this finish is no easy feat. It requires a lot of patience, skill, and a whole lotta elbow grease. 

The bladesmiths use different grades of abrasive materials, like sandpaper and polishing compounds, to gradually work their way up to a mirror-like finish.

It’s like they’re giving the blade a spa day, but instead of a facial, it’s getting a shiny new surface.

The process of making a Japanese mirror polish knife involves several stages of forging, heat-treating, grinding and polishing. 

Here are the basic steps:

Forging

The blade is first forged from a piece of high-quality steel, typically high-carbon steel.

The steel is heated and hammered into shape by a skilled blacksmith using traditional forging techniques.

Heat treatment

After the blade is forged, it undergoes a heat treatment to harden the steel and improve its strength and durability.

The blade is heated to a high temperature and then rapidly cooled in a quenching medium such as oil or water.

Grinding

The blade is then ground to its final shape and sharpened by a skilled grinder. This stage involves removing rough edges and shaping the blade to its desired profile.

Polishing

The polishing process is where the blade truly begins to take on its mirror-like finish.

The blade is first polished using coarse abrasive stones to remove any scratches or imperfections. Then, finer and finer abrasive stones are used to create a smooth, reflective surface.

Finally, polishing compounds are applied to the blade to achieve the final mirror-like finish.

The entire process of making a Japanese mirror polish knife can take several weeks or even months to complete and requires a high level of skill and attention to detail.

The end result is a beautiful, high-performance knife that chefs and knife enthusiasts around the world prize.

So, there you have it, folks. Japanese bladesmiths are the real deal, and their mirror knife finish is just the icing on the cake. 

If you ever get to hold one of their knives, just remember to admire the craftsmanship and try not to blind yourself to the reflection.

How is the kyomen knife polished?

Kyomen finish is achieved by polishing the blade of a knife with a particular type of abrasive stone called a “whetstone” in a single direction. 

The process involves using the whetstone to remove imperfections or blemishes from the blade to give it this super shiny and smooth look. 

There are two main methods for achieving a mirror finish: mechanical and chemical.

Mechanical polishing involves using abrasive materials like sandpaper or polishing pads to buff the metal surface until it’s smooth and shiny.

It’s a bit like giving your kitchen counters a good scrub, but on a much smaller scale.

Chemical polishing, on the other hand, uses special solutions to remove any remaining imperfections and create a reflective surface.

It’s like giving your metal a spa day – complete with facials and massages.

Both methods can be used together to achieve the ultimate mirror finish. It takes a bit of time and effort, but the end result is worth it. 

What you need for a Japanese mirror knife finish

To achieve a Japanese mirror knife finish, you need to use whetstones.

These stones come in different grit sizes (see my review here), and the particular grit you need depends on the type of knife you are sharpening. 

Some popular whetstone brands for Japanese mirror knife finishing include Shapton, Suehiro, and Atoma.

Kuromaku is a specialized type of ceramic whetstone that is particularly useful for Japanese mirror knife finishing.

It is recognizable by its black color and comes in various grit sizes.

Before using your whetstones, you need to soak them in water.

To save time and labor, you can use water absorption agents like Tomo Nagura or Magnesia Suehiro.

These agents help to speed up the soaking process and make it easier to dry the stones after use.

To achieve a mirror finish, you must use polishing agents like Debado LD Series or Gouken Kagayaki.

These agents help fix cracks or rough spots on your blades and make them smoother and shinier.

To maintain a flat surface on your whetstones, you need to use a flattening plate.

Some popular flattening plates include the Super Atoma Diamond Plate and the Large Surface Grinding Plate.

Mirror finishing is the process of polishing a knife blade to a mirror-like finish.

This process involves using a series of abrasive materials to remove any scratches or imperfections on the blade’s surface.

Achieving a mirror finish requires patience, skill, and attention to detail.

What are the advantages of a mirror polish knife finish?

A good mirror finish on a Japanese knife looks impressive and has practical benefits.

There are several advantages of the mirror polish Japanese knife finish, including:

• Improved cutting performance: The mirror-like surface of the blade reduces friction between the blade and the food being cut, resulting in a cleaner and more precise cut.
• It also helps to prevent food from sticking to the blade, which can be a common issue when using a dull or poorly maintained knife.
• Easier maintenance: The smooth surface of the blade makes it easier to clean and maintain. It is less likely to accumulate food particles or stains, which can be difficult to remove.
• Enhanced durability: The mirror polish finish helps to protect the blade from rust and corrosion, which can extend the life of the knife.
• Aesthetically pleasing: The mirror-like finish of the blade is visually appealing and can add to the overall beauty of the knife. It is often considered a hallmark of high-quality Japanese knives.
• Precision sharpening: The mirror polish finish allows for more precise and accurate sharpening, which can help to maintain the sharpness of the blade for longer periods of time.

Overall, the mirror polish Japanese knife finish is a desirable feature for those who value high-performance, quality knives that are both functional and beautiful.

What are the disadvantages of a Japanese mirror polish knife finish?

While the Japanese mirror polish knife finish has many advantages, there are also a few potential disadvantages to consider:

• Scratches: Despite its smooth and reflective surface, the mirror polish finish can be susceptible to scratches, especially when the knife is used on hard or abrasive surfaces. These scratches can detract from the overall appearance of the knife and may require additional polishing to remove.
• Cost: The process of achieving a mirror polish finish is a labor-intensive and time-consuming task that requires a high level of skill and expertise. As a result, knives with this finish tend to be more expensive than those with other types of finishes.
• Fragility: The mirror polish finish can be relatively fragile compared to other types of finishes. Dropping the knife or accidentally hitting it against a hard surface can cause the polish to chip or scratch, requiring additional polishing to restore the finish.
• Maintenance: While the smooth surface of the mirror polish finish makes it easier to clean and maintain, it also requires more frequent cleaning to keep the blade looking its best. Any residue or stains on the blade can be more visible on a mirror-like surface.

Overall, the disadvantages of the Japanese mirror polish knife finish are relatively minor compared to the benefits that it provides.

However, they are worth considering when selecting a knife with this type of finish.

Differences: how Kyomen compares to other Japanese knife finishes

Let’s see how you can tell a kyomen finish apart from other popular Japanese knife finishes.

Kyomen vs Kasumi 

Mirror polish and kasumi finishes are two different polish finishes commonly found on Japanese knives.

Kyomen knife finish, sometimes referred to as the “mirror finish,” is the most common high-polish finish seen on Japanese kitchen knives. 

Both of these finishes are polished, but kyomen is much shinier than kasumi.

It is achieved by polishing a blade with alternating strokes in multiple directions. The result is a highly polished and reflective surface that looks like a mirror. 

This type of finish is usually applied to softer iron alloys and results in a blade that is highly resistant to corrosion.

Kasumi knife finish, on the other hand, is achieved by taking two different grades of steel and hammering them together. 

The result is a blade that has a distinctive pattern along the edge of the knife, with alternating light and dark lines. 

This type of finish is used on harder iron alloys and results in a more durable blade than one with a Kyomen finish.

Kasumi knives require less maintenance and can hold an edge longer than those with a mirror finish.

They also have fewer spots where rust can form, making them ideal for use in wetter environments.

Kyomen vs migaki 

The Migaki knife finish is similar to kyomen but with a few differences.

Migaki knives are finished with fine abrasives, just like kyomen, but they’re not as shiny and smooth.

These blades are polished until they have a bright, silky gleam, but they’re not quite like a mirror.

The degree of polishing applied by one bladesmith versus another will differ.

Since different manufacturers make Migaki knives, their reflectiveness will also be different.

It’s possible to get a mirror-like shine from some manufacturers, while others produce a cloudy finish.

Compared to the mirror-finish kyomen, the migaki knives have a more subtle look.

They’re less prone to smudging and fingerprints but still retain the gleam of polished blades.

Migaki knives are slightly stronger than kyomen, although they require more maintenance because they’re not as resistant to corrosion. 

They’re also more susceptible to water damage and require frequent sharpening due to their softer steel construction.

Kyomen vs Nashiji 

Let’s talk about the difference between kyomen and nashiji knife finishes.

Kyomen is a fancy Japanese term for a smooth and polished knife finish.

This type of finish is great for those who want a knife that looks sleek and shiny, like a brand-new penny.

It’s perfect for impressing your dinner guests with your fancy knife skills.

On the other hand, nashiji is a Japanese term that refers to a textured knife finish, also called a pear skin finish. 

It’s like the difference between a smoothie and a milkshake.

Nashiji has a rougher texture, almost like sandpaper, which makes it great for those who want a knife that’s easy to grip and won’t slip out of your hand like a bar of soap. 

Plus, the texture adds a little extra flair to your knife collection. The pear skin finish also ensures the food doesn’t stick to the sides of the blade. 

Now, you might be wondering which one is better. Well, that’s like asking if pizza or tacos are better. It all comes down to personal preference.

Do you want a knife that looks like it just came out of a showroom, or do you want a knife with a little extra grip and personality? It’s up to you, my friend.

Kyomen vs Damascus 

Kyomen is the smoothest knife finish which is polished until it has a mirror-like appearance.

Damascus knife finish, on the other hand, is achieved through a process of folding and hammering two types of steel together. 

This results in a blade with an interesting pattern, usually consisting of alternating light and dark lines.

The Damascus finish is distinctly different from the Kyomen.

It’s often more rustic-looking due to its pattern and is usually used on harder steel alloys.

It’s also known for its excellent edge retention, making it a great choice for outdoor use.

The main difference between the two is their appearance.

The Kyomen finish is mirror polished and reflective, whereas the Damascus has a wavy or water-patterned look. 

The Kyomen will also require more maintenance to keep it looking like new due to its higher susceptibility to corrosion.

Kyomen vs Kurouchi 

Kyomen finish is like the pretty boy of the knife world.

It’s all about the smooth, polished surface that makes your knife look like it just came out of a spa day. 

Think of it like a fancy sports car with a sleek, shiny exterior.

It’s perfect for those who want to show off their knife skills and impress their guests with a knife that looks like it belongs in a museum.

On the other hand, we have the kurouchi finish, which is like the rugged, bad boy of the knife world.

It’s all about the rough, unpolished surface that gives your knife a raw, edgy look. Think of it like a motorcycle with a matte black finish. 

It’s perfect for those who want a knife that can handle some serious chopping and slicing without worrying about scratches or dings.

The Kurouchi finish is rough and unfinished, looking with a light black color. 

But it’s not just about looks, folks. The kyomen finish is great for precision cutting and slicing, thanks to its smooth surface that glides effortlessly through food. 

Meanwhile, the kurouchi finish is perfect for heavy-duty tasks like chopping through bones and tough vegetables, thanks to its rough surface that provides a better grip.

Kyomen vs Tsuchime

Tsuchime knife finish results from a process in which an acid-etched hammer pattern is applied to the blade.

This finish adds an interesting texture and look to the knife, but it does not provide any additional protection from corrosion.

The tsuchime finish is a hand-hammered pattern, and this surface ensures food bits don’t stick to the sides of the blade.

Kyomen, on the other hand, is a mirror-like polished finish that looks stunning and makes the blade extremely corrosion-resistant.

This type of finish requires more care and maintenance to keep it looking new since it is more prone to rusting and staining.

When it comes down to it, the main difference between Kyomen and tsuchime is their appearance. 

The Kyomen finish has a more reflective look, while the tsuchime finish has an interesting texture and dimpled pattern.

FAQs

What surface finish is a mirror finish?

So, you want to know what a mirror finish is? 

Well, let me tell you, it’s the shiniest, smoothest surface you can imagine!

It’s like looking into a crystal-clear lake on a sunny day – you can see your reflection perfectly. 

This finish is achieved by using special techniques like grinding, polishing, and even electric sparking to remove any imperfections and create a surface that’s so shiny, it’s reflective. 

Now, you might be wondering why someone would want a mirror finish. Well, let me tell you, it’s not just for vanity! 

A mirror finish has some practical benefits too.

For one, it improves the service life of mechanical components by reducing wear and tear. Plus, it looks darn good! 

But achieving a mirror finish isn’t easy. It requires some serious skill and specialized tools.

Skilled Japanese bladesmiths spend lots of time polishing each blade until it’s mirror-like!

Is mirror finish blade expensive?

So, you’re wondering if mirror finish blades are expensive? Well, let me tell you, my friend, they can definitely put a dent in your wallet. 

These shiny blades are like the luxury cars of the knife world – they look sleek and impressive, but they come with a hefty price tag.

Now, you might be thinking, “Why are these blades so darn expensive?” Well, it all comes down to the time and effort spent creating that mirror finish.

Most premium honyaki knives (review here) tend to have a mirror finish, and this is quite expensive (think upwards of $1000 per knife)!

It’s not just a matter of slapping on some polish and calling it a day. No, no, no.

Craftsmen must use buffing wheels and carefully sand by hand to achieve that perfect, controlled mirror finish.

And let me tell you, that takes a lot of skill and patience.

But don’t worry, my frugal friend; there are cheaper options out there if you’re willing to sacrifice a bit of that mirror finish perfection. 

You can still get a mild polish that removes patina and restores shine without breaking the bank.

Just be aware that these cheaper options might not be as impressive to show off to your friends.

So, to sum it up, mirror finish blades are definitely pricier, but they’re worth it if you want that jaw-dropping, salami-slicing, finger-print-attracting shine. 

Just be prepared to shell out some serious dough or put in some serious elbow grease if you want to achieve that mirror finish yourself.

Does the kyomen finish scratch easily?

Kyomen knives are generally scratch-resistant due to the mirror-like finish.

The steel is buffed until it has a glassy shine, and it can resist corrosion, staining, and wear better than other finishes.

However, it is important to remember that kyomen knives require more maintenance, so it is important to take care of them properly.

But the reality is that, of course, a scratch can show up on this type of finish, but it should be easily buffed out with a soft cloth or light sandpaper.

Compared to other finishes, kyomen offers the added benefit of looking brand new with a simple polish.

Conclusion

The Japanese mirror knife finish is a traditional knife sharpening technique that involves a series of abrasive materials to remove scratches and imperfections from the blade, creating a smooth and shiny surface.

It’s not for everyone, but if you’re looking for a knife with a beautiful, shiny finish, it’s worth the effort! 

So, if you’re looking to buy a Japanese knife, you should ask the seller if the blade is “nihongata dekirun desu ne?” (Is it Japanese mirror finished?)

Because it’s a knife you’ll use every day, you deserve the best!

I have reviewed the best Japanese knives you can buy at the moment here (read my buying guide!)

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Joost Nusselder, the founder of Bite My Bun is a content marketer, dad and loves trying out new food with Japanese food at the heart of his passion, and together with his team he's been creating in-depth blog articles since 2016 to help loyal readers with recipes and cooking tips.