What Makes A Good Knife?


There's thousands upon thousands of knives out there. Varying angles, styles, materials, and importantly prices.

But what exactly makes a good knife?

This is a broad question, and you'll get different answers depending which craftsperson you ask. For example, we're a company that has supported professional chefs and blacksmiths for 70 years, taking their feedback, advice and needs. Plus, we have a general focus on sharpness in a knife. This article is our take and answer to the important question of what makes a good kitchen knife.

We have also released an educational video in Japanese with English subtitles (turn them on via YouTube settings) on this at our Hocho no Koto channel. Watch it below!


The qualifiers of a good knife

Let's define what we think a "good" knife is before anything else. To us, there's three main categories to focus on, each with sub-categories inside it. At a base level though, we judge knives based on:

 

  1. Kireaji/"Sharpness"
  2. Balance
  3. Maintenance Characteristics

 

We'll delve into each of these categories in detail throughout this article, and you can weigh them based on what categories are important to you.

A key thing to remember is this is what we think a good knife is - what is good for you might be different! Use this as a general guide, and build off it.


Kireaji - "Sharpness" defined

While kireaji can translate as "sharpness," in this case with Japanese context it can be referred to it more as the "taste" of sharpness. Or in a way, the "feeling" behind the cutting of something.

Realistically though, it doesn't have an equivalent word in English.

Kireaji is very much a term of it's own, and in Japan, this is kind of a unique cultural expression that captures the concept of "how it cuts." For instance, while the English word "sharpness" is translated as surudosa in Japanese, the nuance of kireaji is slightly different. If directly translated it comes out as "flavor of cutting," which is quite confusing. Similarly, in many other languages, there isn't a perfect equivalent for kireaji.

In Japan, there's a diverse range of sensations associated with kireaji. For example, there's the concept of amagire or "sweet cut," which describes the feeling of a knife cutting smoothly even without being extremely sharp (we go into this concept more in our blog about Blue Steel #2.) This also implies that the cutting technique itself contributes to the taste. For example, when slicing fish, even just the method of cutting alone is enough to create or identify a dish. This promotes the notion that how something is cut is crucial to how it tastes.

Perhaps this is one of the unique Japanese cooking perspectives that has elevated Japanese knives to be recognized and valued worldwide.

Our company's concept of kireaji

With our store and team, we believe kireaji can be broken down in three seperate components, which we will also use the Japanese terms for:

 

  1. Nagikire, which refers to how well sharpness can be kept with proper usage (think edge retention - lit. Eternal Cutting)
  2. Iriyasusa, which refers to how well a knife pierces into an ingredient (penetrative ability - lit. Ease of Entrance)
  3. Susumiyasusa, which refers to how smoothly a knife cuts after it's entered an ingredient (cutting ability - lit. Ease of Continuation)

 

Good nagikire differentiates expensive and inexpensive knives. By not compromising on materials or creative processes, we're able to produce knives that cut for a long time and as a result have excellent edge retention and thus, a great nagikire.

A good iriyasusa is generally indicated by the composition of the blade steel. A finely honed and well-maintained edge down to the micro level combined with the right steel will give amazing penetrative ability. A well-forged knife with the same metal composition throughout will have a firm edge, even when magnified to a microscopic level.

A good susumiyasusa mostly comes down to how the knife blade itself is processed, such as with honing and sharpening techniques. The tip of a knife has a thin edge, but as the knife cuts into an ingredient (such as with a deba knife for example) you'll notice it gets thicker. Keeping the blade thin and with a properly rounded curve creates a cutting edge referred to as a "clam-shell blade" or hamagui ha, which can cut without food sticking to the blade, this giving it great contiunous cutting ability. Conversely, if the blade is thin but does not have the adequate strength or form, it won't be able to maintain its pressure against the ingredient its cutting, making it more difficult for the knife to properly and continously cut through. You might discover this trait this more easily while cutting harder root vegetables like sweet potatoes.

In short, for us a knife with good kireaji holds its sharpness well, penetrates into ingredients easily and has a sharp general cutting ability, without catching on the ingredients.


Balance

The second key factor is the balance of a knife - that is, how it feels when it is held and more importantly when it is used. Sadly, there's no real "correct" answer to this as everyone's hands are different in terms of size and grip strength amongst other things. Even if we claim a knife "has excellent balance," it simply may not for you because your hand is different to the hands from people in our store - we simply don't know how well the knife balance might apply to another user. Of course, this can go vice versa too - a knife that works for you balance wise may simply not work for us.

The best way to solve this issue is to go to a knife store and hold the knives to compare, and we recommend this everytime customers come into our shop in Osaka. But of course, this isn't always possible - there's a good chance if you're reading this you're on a global website and not in Japan for example. So to try to solve that in our own way, we split how we measure balance into three seperate sub-categories.

 

  1. Ease of grip
  2. Resistance to fatigue
  3. Ease of power transmission

 

Ease of grip is simple to explain - how well the handle fits into your hand. If it's easy to grip, there's no need for excessive force. While there's many stylish handles out there these days, for those using a knife for a long time in a day how easy it is to grip is really important. This handle needs to be able to grip while cutting, peeling, doing push cuts and all kinds of other movements.

Resistance to fatigue is how well you can hold the knife without getting tired. We often see Japanese handled-knives perform well here due to their lighter weight, but sometimes people prefer to use heavier knives for a long time and let gravity do some of the work.

Ease of power transmission is how well a suitable center of gravity is created in the knife. A knife with a good weight balance between the blade and the handle will transmit power easier, and be less tiring to use. If the tip of the blade is heavy, it becomes difficult to aim, but that weight can also be used to an advantage by letting gravity assist you. Additionally, if the handle side is heavy (like in Western-handled knives) it can be difficult to do delicate work because the cutting edge is controlled by the arm more than the wrist. Ceramic knives are a great example of this, as while they're very innovative thanks to their extremely light and sharp blade for their price, their center of gravity is all the way over on the handle side, so it takes getting used to.

Gyuto and santoku knives should have their center of gravity where the index finger rests, whereas Japanese-handled knives should have it around the base of the blade. The material of the handle itself and whether or not it has a bolster changes the center of gravity heavily, so keep this in mind when you're considering purchasing off the internet and not being able to hold it first.

Where possible, try to hold the knife - see if it fits right in your hand and feels good to use.


Maintenance Characteristics

Maintenance Characteristics can also be referred to as how well sharpness on a knife can be reproduced. This is crucial if you're aiming to have a knife that will last for a lifetime, especially if you're investing into a good quality knife. We feel maintenance characteristics include the following three sub-categories:

 

  1. Rust resistance
  2. Ease of sharpening
  3. Chip resistance

 

Rust resistance very much is what it says - how resistant a knife is to the natural chemical reaction of rusting. While carbon steel knives can be made at a cheaper cost and maintain the same sharpness as other steels, they require regular care to prevent rusting. This is especially important after using and washing them, like making sure they are fully dry and removing all moisture. Rust is the number one enemy of knives, as it can cause significant steel deterioration leading to pitting in the knife or even transferring the rust into food. Stainless steel knives in comparison, are significantly more resistant to rust compared to carbon steel, offering much more peace of mind in terms of general knife maintenance and generally perform well in this subcategory.

Ease of sharpening is measured by how simple it is to place a blade on a whetstone and get a good cutting edge. A blade will ultimately always consist of a thinly honed metal that will need to be resharpened as it's used. While higher quality steels allow for sharper edges, the finer the edge, the more susceptible to rounding it is when it strikes the cutting board or a harder substance like bone. High quality steels are thankfully resistant to wear and rounding, resulting in longer-lasting sharpness. However, this generally also comes with the caveat of being difficult to sharpen, creating a trade-off between ease of sharpening and good edge retention. That said, thanks to the effort of cratsmen, steel manufacturers and whetstone makers, there are knives that manage to excel in both areas, or the knives may feature a wear-resistant, yet easy to sharpen steel - generally this is due to its thickness. When choosing a knife to be a long-term item, we tend to recommend prioritising how easy it to sharpen over edge retention. There's no such thing as a knife that doesn't need resharpening so this is always a factor you need to consider. We love sharpening though, so maybe it's not such a bad thing.

Chip resistance refers to both chipping resistance and impact resistance, such as when the knife hits something hard or is dropped. A knife is made chip-resistant by being well forged, with a good carbon composition evenly throughout the blade steel, by using a durable steel in itself, and by sharpening the blade properly during it's bladesmithing process. Chips are a big enemy of knives, as they require significant sharpening to fix, heavily impacting the total lifetime of a knife. It's important to factor this in, even if you think you'll never drop the knife.


Which major factor is most important?

All three major factors above play a big part in a knife's general performance. However, what we feel supports these elements the most is your personal attachment to the knife. As cheesy as it may sound, when it's a long-term item designed to use for a lifetime it's quite important and can't afford to be underestimated.

Whether you're a professional, or just cooking in the home it's true that even with high-quality knives, over time its sharpness will decline. If there's no personal attachment to the knife, the way it's used over time might become more careless, leading to dullness, chips or even rust.

Actions like engraving your name (which we do for free on all knives sold with us - even online,) or buying the knife based on appearance may seem unrelated to the actual performance of the knife itself, but they can contribute to a more positive mindset when using the knife and maintaining it, leading to a better quality knife overall.

In short, a lot of a knife's performance comes down to how you care for the knife after you acquire it. Remember, a sharp knife that is more inexpensive is better than a blunt knife that is expensive. So you'll want a knife that you really want to take care of.


What determines kireaji, balance and maintainability?

In short, we feel a good knife is one that's sharp, well-balanced, easy to maintain and is one you feel personally attached to. Attachment is something you foster between yourself and a tool, so we can't comment too much on that - but we have briefly summarized what determines the remaining factors in a table below.

Steel Material Heat Trt./Frg. Edge Sharp. Handle Attch.

Kireaji

Bal.

Maint.

Steel Material Heat Treatment + Forging Edge Sharpness Handle Attachment

Kireaji / "Sharpness"

Balance

Maintenance Characteristics

By choosing a knife that combines the factors of kireaji, balance and maintainability, while also not being swayed solely by the name of a steel or just on appearance alone (but it's good to consider it,) you'll wind up with a knife that feels good, that you like and that you'll foster a connection with over time.

That knife, now as your cutting partner should serve you well for a lifetime. We're always here to help you find that, so feel free to contact us anytime for guidance.