Kurouchi Knife Finish: Unpolished After Forging for a Rustic Look

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Japanese knives come in a variety of different finishes, but there’s this rustic, dark-looking finish that makes the blade look old or unfinished, but this is ACTUALLY something many chefs specifically look for!

A kurouchi finish, or blacksmith finish, is a traditional Japanese method of finishing knives. It involves using charcoal to burnish the blade and create a dark, textured surface. This texture helps hold onto oils from food and prevents rust build-up while providing an attractive matte look to the blade. 

So, what is this knife finish, and why is it desirable? In this article, I’ll explain what it is and we’ll talk about its advantages and disadvantages.

Kurouchi Knife Finish: Unpolished After Forging for a Rustic Look

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What is a Kurouchi knife finish?

Kurouchi knife finish is a traditional Japanese blacksmithing technique that involves leaving the forge scale on the blade, giving it a rustic, dark appearance that can be smoother or textured, depending on the bladesmith. 

A Kurouchi finish can look matte, in stark contrast to a super polished Migaki finish

This Japanese blade finishing method involves leaving the forge scale on the blade.

The forge scale is a layer of oxidation that forms on the steel when heated. This layer of oxidation gives the blade a dark, rustic appearance.

Kurouchi knives are known for their durability and sharpness, as well as their unique look. Also, it will reduce the reactivity of a carbon steel knife.

The Kurouchi finish is achieved by heating the blade to a high temperature and then quenching it in oil.

This process creates a hard, protective layer on the blade that helps to protect it from corrosion and wear.

The Kurouchi finish is the lowest form of polishing, and it doesn’t require as much work by the bladesmith.

However, many Japanese people like this finish because it ages very well and it offers improved food release. 

It’s important to note that Kurouchi is the least polished of the popular Japanese knife finishes.

It is a conventional and unpolished finish, and the knife will still have the forging process’s black, scaly residue on it. 

The Kurouchi finish’s black forged patina is extremely inexpensive and significantly lowers production costs because it is not refined.

Therefore, these knives are almost always less expensive. 

There’s one disadvantage, though: the kurouchi finish can rust faster than other finishes, but as long as the knife is maintained properly, it’s not really an issue. 

Kurouchi knives are often used in professional kitchens, as they are highly durable and can stand up to the rigors of daily use.

They also have a unique look that can add a touch of style to any kitchen.

Gyuto, santoku, and kiritsuke are some popular kurouchi finish knives. 

Yoshihiro makes a gorgeous (albeit pricey) Black-Forged Gyuto Chefs Knife if you want a versatile knife with a kurouchi finish.

gorgeous (albeit pricey) Black-Forged Gyuto Chefs Knife if you want a versatile knife with a kurouchi finish

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All Japanese knives can have a kurouchi finish but since these are considered low-polish blades, they’re not as popular with people.

Most chefs and home cooks prefer a smooth polished look (Migaki) or the famous hammered finish (Tsuchime)

What does Kurouchi mean?

The term kurouchi in Japanese is translated as ‘first black’ in English or can also mean ‘blacksmith’s finish’.

It is a reference to the traditional Japanese method of blacksmithing that is used to create Kurouchi knives.

The term described how the blacksmiths would burnish the blade using charcoal and leave behind a dark, textured finish on the blade. 

So, first black is a reference to the unfinished aspect of this particular blade finish. 

Does a Kurouchi finish matter?

In reality, the visual differences between the different finishes have no impact on how well the knives function.

Some chefs claim that certain finishes are better than others because they ensure food doesn’t stick to the blade. 

Therefore, some cooks may swear that particular finishes perform better or make it easier for food to brush off the blade than others.

However, this is entirely arbitrary. 

A kurouchi finish is an aesthetically pleasing finish for some while others think it looks unfinished and ugly. 

So, is the kurouchi finish functional?

Overall, no. But, as some chefs point out, it can aid them while cooking.

Kurouchi knives are known for their durability and strength although the finish will still wear off after time. 

The finish creates a smoother blade, which helps to reduce friction when slicing and sharpening.

Additionally, the blacksmith finish prevents food from sticking and rusting to the surface of the knife, meaning less maintenance is required over time.

Ultimately, Kurouchi knives are a great addition to any kitchen.

They’re perfect for chefs and home cooks alike who appreciate the natural look and feel of traditional blacksmithing. 

With their durable properties, minimal maintenance requirements, and attractive matte finish, Kurouchi knives are sure to bring both style and functionality to your culinary adventures.

However, it’s important to note that the kitchen knife’s performance will be more influenced by knife technique than by its cosmetic finishes. 

But it’s fair to say that the appearance of the knife might affect someone emotionally. 

Cooking with lovely utensils increases the likelihood that you will feel a connection to them and enjoy your work.

Some people get extremely passionate about cooking due to the high-quality tools and utensils they employ. 

If you are serious about sharpening your knives, consider buying a sharpening jig for a super precise angle (review)

Why is a kurouchi knife finish important?

Kurouchi finish is important because it adds a unique look and feel to knives. It gives them a rustic, traditional look that can’t be achieved with other finishes.

This can be appealing to those looking for traditional Japanese knives.

A new gyuto with a kurouchi finish can actually look like it has gained patina over time and it can look like an old authentic knife you inherited from grandma. 

But kurouchi also adds a layer of protection to the blade, making it more durable and resistant to corrosion. 

Plus, it’s a great way to show off the craftsmanship of the knife maker.

Kurouchi finish also adds a unique texture to the blade, making it easier to grip and more comfortable to use. 

Finally, it’s a great way to add a bit of character to a knife, making it stand out from the crowd.

All in all, kurouchi finish is an important part of knife making and adds a lot of value to a knife.

How is a kurouchi finish made?

The traditional Japanese blacksmithing technique used to create Kurouchi knives has been passed down through generations. 

Kurouchi is just simply forge scale from heat treating and forging. 

Dark iron oxides grow on the surface of steel when heated to the temperatures needed for forging or heat treating in an oxygen-rich atmosphere. 

In western knifemaking, the kurouchi layer is often referred to as brut de forge.

The process starts with the blacksmith using charcoal to heat and burnish the blade of the knife. 

This burnishing creates a dark, textured surface without any additional polishing or buffing.

After that, the blade is quenched in oil or water to cool it down and that’s it — the Kurouchi finish is complete!

The process of blacksmithing is what gives Kurouchi knives their unique look and feel.

It requires precise control over heat, timing, and technique to achieve the desired result.

What is the history of kurouchi knife finish?

Kurouchi knife finish has been around for centuries.

It was first developed in Japan during the Edo period (1603-1868) by swordsmiths who wanted to create a durable, rust-resistant finish for their blades. 

Some say this more rudimentary finish was developed by master swordsmiths in the late 16th century which is likely true. 

The technique involves applying a layer of carbonized clay to the blade, which is then heated and quenched in water.

This creates a hard, black finish resistant to corrosion and wear.

Over the years, Kurouchi knife finish has evolved and become more popular. It has been used on various knives, from kitchen knives to hunting knives. 

In recent years, it has become a popular choice for chefs and home cooks alike due to its durability and rust-resistant properties.

Find out how to clean a Japanese knife again that has gotten rusty

How to clean Kurouchi finish knife?

Kurouchi knives are relatively low-maintenance and do not require much special care.

However, as with any knife, it is important to clean and oil the blade ocasionally.

Doing this will help keep the matte finish looking fresh and prevent rust or discoloration.

To clean a Kurouchi finish knife, you should use a soft cloth and warm soapy water. Do not use abrasive materials or scrub too hard, as this can cause damage to the blade.

Once the knife is clean, wipe it dry with a towel and apply a thin layer of vegetable oil to protect the surface.

Remember not to place a knife with a kurouchi finish in the dishwasher, as this causes the finish to wear off quickly.

Besides, dishwashers tend to ruin precious Japanese knives!

Finally, store your Kurouchi-finished knives in a clean, dry place to prevent rust.

Its important to remember that these knives do not require frequent cleaning and oiling — only when needed.

Learn more about proper Japanese knife care and maintenance here

Kurouchi vs Nashiji

Kurouchi is a type of Japanese knife finish that is left unfinished, with the steel left exposed. This gives the blade a rustic look and feel. 

Nashiji is a type of Japanese knife finish that is polished, giving the blade a smooth, glossy look with a specific pattern like a nashi pear. 

The Kurouchi finish is more durable and can withstand more wear and tear, while the Nashiji finish is more aesthetically pleasing.

Kurouchi vs Tsuchime

Kurouchi is a type of Japanese knife finish that is left unfinished, with the steel left exposed. This gives the blade a rustic look and feel. 

Tsuchime is a type of Japanese knife finish that is hammered, giving the blade a textured look.

These blades have small dents in them and prevent food from sticking to the sides of the blade. 

The Kurouchi finish is more durable and can withstand more wear and tear, while the Tsuchime finish is more visually appealing. 

FAQs

Does Kurouchi finish have patina?

Patina is a thin layer of oxidation that forms on the surface of metal over time. 

It is often seen on knives with a Kurouchi finish, as the oxidation helps to protect the blade from corrosion. 

Patina can also give the blade a unique look, as the oxidation can create a variety of colors and patterns.

But patina and kurouchi finish are two different things. The kurouchi is just a type of knife finish.

Patina is the layer that appears on the metal as time passes. It’s the true sign of wear and tear. 

Is Kurouchi the same as first black finish?

Yes, these two terms refer to the same unrefined and brute knife finish also known in Japanese as kurouchi.

First black is a type of finish that is created by heating the blade to a high temperature and then quenching it in oil. 

This finish is often seen on traditional Japanese knives, and is also referred to as a “Kurouchi” finish.

The finish is created by heating the blade to a high temperature and then quenching it in oil, creating a dark, matte finish.

Does Kurouchi finish wear off?

Yes, Kurouchi finish can wear off over time. This is because it is a rustic finish that is not polished or buffed. 

It is created by heating the blade to a high temperature and then quenching it in oil.

This process creates a protective layer of carbonized steel on the blade that is very durable, but it is still susceptible to wear and tear. 

The Kurouchi finish will start to wear off if the blade is used often and not cared for properly.

How is Kurouchi finish different from other Japanese knife finishes?

Kurouchi finish is different from other Japanese knife finishes because it is not polished or buffed. 

It is created by heating the blade to a high temperature and then quenching it in oil.

This process creates a protective layer of carbonized steel on the blade that is very durable. 

The Kurouchi finish gives the blade a unique rustic look that is characteristic of traditional Japanese knives. 

Other Japanese knife finishes, such as Hon Kasumi, are polished and buffed to create a more refined look.

Kurouchi is preferred by those looking for a more rustic, unfinished look to their blades. 

Conclusion

A kurouchi finish is a traditional Japanese knife finish that gives the blade a unique look and feel, and now you know it’s a GREAT option for anyone looking for a unique and stylish knife. 

The defining feature of this finish is its dark, rustic appearance and it ages pretty well. With proper care, you can enjoy your kurouchi finish knife for many years to come.

Read next: How Long Can Japanese Knives Last?

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Bitemybun's family recipes with complete meal planner and recipe 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.