An Introduction to Knife Sharpening

When we receive maintenance or sharpening requests from customers, sometimes we handle knives that have been cherished for decades, such as those purchased when they got married or heirloom knives that have been passed down from deceased parents.

A really good knife is not only become lifelong tools but are also passed on to future generations.

However, using high-end knives without proper knowledge (we have a blog about how to use knives you can read here!) can lead to issues such as rusting, significant edge damage during use like chipping, or even misshaping of the knife due to incorrect sharpening techniques. In a very short period of time, a valuable knife can become difficult to use, or even unusable.

For those who cook, knives are everyday tools and if you've invested in a good knife, you'll likely want to use it for as long as possible.

To achieve this, it's crucial to understand the reasons knives may deteriorate and learn appropriate methods for addressing each situation.

There is joy to be found in nurturing and caring for your knives. Let's explore this deeper by answering some key questions.

Why do knives become dull or lose their sharpness?

As with almost anything sharp, knives gradually lose their sharpness with each use.

But why does this happen?

The answer is fairly simple: the blade edge wears out and gradually becomes rounded, making the knife unable to cut effectively. You might notice things are harder to cut through than before with a used knife that has not been sharpened. A tomato might give resistance when it didn't used to, or a loaf of bread might compress when you cut through it.

If you try sliding a knife that has lost its sharpness across your fingernail, you'll notice that it smoothly glides without any resistance (of course, be careful trying this!).

See the diagram below for an example:

So, what causes a blade's edge to wear out?

Many people might think it's because of the ingredients they're cutting in their cooking. However, most food items are softer compared to the knives cutting through them, and they aren't the primary reason for dulling the blade.

The real culprit is the cutting board—plain and simple.

When cutting ingredients, generally people do so directly on a cutting board. While it may not be something you think about, you're simultaneously cutting not just the food but also the cutting board slightly when you cut through something.

Now, why doesn't the cutting board change state? This is because the cutting board is significantly harder compared to the ingredients being cut on it. As a result, only the soft food gets cut, but the knife wears down as it hits the harder surface of the cutting board, leading to a decline in sharpness.

When a blade edge is rounded, a knife can be considered as blunt. In turn, a sharp knife is one where the blade edge is keen and cuts well. To restore a knife to its original performance, we sharpen it.

However, blindly sharpening without knowing the correct technique will not restore the blade, and there's a risk of actually damaging or chipping the knife. It's crucial to first learn the correct sharpening technique, ensuring that you can continue using your cherished knife with affection.

The combination of the best knife with the finest sharpening is what creates the ultimate sharpness. Both are equally important.

Sharpening Japanese Kitchen Knives (Wa-Bocho)

Traditional Japanese kitchen knives are predominantly single-edged, designed to achieve the cleanest possible cuts on ingredients as that sharpness can be focused to a single point. This allows for a variety of shapes tailored to cut various ingredients, each with its own suitable sharpening techniques. How you sharpen a deba knife compared to an usuba or yanagiba knife for example might be different - which is why we have seperate guides on them (with more to come!)

Below are some useful pages from us on how to sharpen specific knives - this will be updated over time so if you don't see your knife here, check back in soon or contact us!

• How to Sharpen a Yanagiba Knife
• How to Sharpen a Deba Knife
• How to Sharpen a Usuba Knife

Sharpening Western Kitchen Knives (Yo-Bocho)

Unlike Japanese knives, many Western knives are double-edged. However, they are not necessarily sharpened on both sides symmetrically. Even with double-edged knives, there are professional techniques you can apply that prioritize sharpness. And of course, unique ways to sharpen each style of knife if you want to get more specific and focused.

Sharpening Household Kitchen Knives (Santoku-Bocho)

For those who have never sharpened a knife before, or are still gaining confidence, techniques you apply to sharpening santoku knives are easier to understand and this is a great springboard point.

You need the right tools to sharpen your knives correctly, otherwise even with the right techniques you might run into problems. An essential tool for sharpening knives is a sharpening stone, sometimes called a whetstone or 砥石 (toishi). However, there are various types of sharpening stones with differences in coarseness (particle size), material, and manufacturing methods. It can be challenging to choose the right one at first, as there's so many styles and brands available - we have a full guide with a more in-depth introduction to whetstones here - but we'll recap the basics in this article too.

Before delving into sharpening, it's crucial to have a proper understanding of the stones you'll be using. Without this knowledge, even if you attempt to sharpen your knife, you may struggle to achieve the desired results, and the knife's sharpness may not return as you were expecting.

Firstly, what kind of sharpening stone should you choose?

Broadly speaking, there are two main types of sharpening stones: "Artificial Stones" and "Natural Stones."

Within artificial stones, there are various classifications based on the coarseness (grit size) of the particles - if you see numbers written on the stone like #220, #1000 or #6000, this is that grit size number. Additionally, there are numerous types of abrasives used as the main ingredient, and manufacturing methods continue to evolve and change.

When it comes to natural stones, as they are natural like the name implies, even stones sourced from the same mountain won't have the same quality. A few centimeters difference in where it's mined from can make all the difference. We have a blog going deeper into natural stones here!

Sharpening stones can be further classified into three main elements: "Coarseness (Grit Size)," "Material and Manufacturing Method," and "Stone Size."

Among these, there are varieties in coarseness, material, and manufacturing methods. As earlier stated, there's a lot to choose from!

Experienced sharpeners might already be familiar with stones that suit their needs. However, for beginners it might be challenging to understand the differences. Let's delve into this in a little more detail so you can understand some basic differences.

Choosing the correct coarseness (grit size)

A very common question from beginners is how to choose their first sharpening stone. The crucial point in selecting a sharpening stone is its coarseness, indicated by the term "grit size" or "番手" (bante) in Japanese.

Grit size is represented by a number following the symbol "#" in the world of knives. A smaller number indicates a coarser grit size, while a larger number signifies a finer grit size. For example, a #220 grit size stone will be rougher than a #1000, which is rougher than a #6000.

The differences in these grit sizes categorize sharpening stones into three main types: "Rough/Coarse Stones," "Medium Stones," and "Finishing/Fine Stones."

Which stone should you choose first?

Each type of sharpening stone has a purpose and ideally, it's recommended to have one of all three types. However, for those who are not yet accustomed to sharpening it might be a little tough to buy all three at first.

If you're buying a sharpening stone for the first time, we recommend starting with a medium stone. The medium stone serves as the foundation for all sharpening, and with this stone, you can restore sharpness to your knife. You can also get double-sided stones to save a little money, at the cost of some stone durability as there is less of each side.

Further information can be found in our dedicated blog - "Choosing a whetstone" - Click here to read!

Importance of Cutting Boards in Maintaining Knife Sharpness

The cutting board plays a crucial role in your knife's longevity and sharpness. While many people emphasize the quality of their knives, the significance of the cutting board is very often underestimated.

The reason the right cutting boards are essential is due to their significant impact on the "sustained sharpness" of knives.

Imagine the process of cutting ingredients, where you might be tapping the knife on the cutting board while chopping. In effect, you're cutting the ingredients and the cutting board at the same time.

The cutting board is much harder compared to most ingredients. Even only cutting soft ingredients, the knife will steadily wear down on a hard cutting board, leading to a decline in sharpness.

Surprisingly, the cutting board is the primary factor contributing to the deterioration of knife sharpness. So be sure when you get a knife, make sure to have the right cutting board for it too. We do have a blog on cutting boards you can read here, but we'll also go through some surface level explanations below.

Choosing the Right Cutting Board

As mentioned earlier, the cutting board significantly influences the usability and lifespan of your knives. Therefore, it's recommended to choose a cutting board carefully, especially if you want to use your knives for an extended period.

There are three main types of cutting board materials: wooden, plastic and rubber. Each has its own characteristics, but we highly recommend using wooden cutting boards. We strongly consider them the most suitable.

The primary characteristic of wooden cutting boards is their soft and elastic nature, providing a good blade feel when cutting through ingredients. This not only reduces the likelihood of blade damage but also minimizes strain on the wrist, making it less tiring to cut for long periods of time. Wooden cutting boards gently receive the blade too, increasing blade durability. Additionally, while this may seem superficial the pleasant sensation when cutting ingredients enhances the joy of cooking when using a wooden cutting board. Cooking is meant to be fun, so we also see enjoyment as an important factor!

In contrast, plastic or rubber-based boards are very rigid, causing the blade to bounce off and quickly diminishing a knife's sharpness. This downside is somewhat negated though by their ease of use and maintenance. They're easy to clean and disinfect compared to wooden cutting boards.

Care and Maintenance of Cutting Boards

Once you acquire a quality cutting board, you'll also probably want to use it for a long time along with your knives. This is especially true for wooden cutting boards, which require proper care during and after use. Failure to do so may result in discoloration, bacterial growth, and overall unsanitary conditions. It's important to be mindful of the specific care methods for each type of cutting board to ensure longevity and hygiene, much like taking care of your knives. Be sure to read instructions that come with your cutting board to care for it properly.

Maintenance of the blade is just as important as maintenance of the board it is making contact with.

Further information can be found in our dedicated blog - "Cutting Boards" - Click here to read!

Knife Care, Storage and Disposal

Mirror Finishes on Knives