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The Correct Japanese Knife Sharpening Angle | It Will Make the Difference


Having a sharp knife can quite literally be the difference between the blade passing effortlessly through food or slipping off and potentially causing an accident. Japanese knives are a work of art and are designed to be strong, tough, and sharp. 

 The sharpness, however, will depend on the angle at which you need to sharpen your knife as this is the sole determining factor as to how sharp your edge will be. The initial angle that the knife was designed with will determine this but how do you know what angle you need to sharpen at? 

 The correct sharpening angle for a Japanese knife is 10 - 15 degrees on one single side. Most Japanese knives are now double bevel meaning the blade needs to be sharpened to 10 - 15 degrees on the other side as well. For double bevel knives, the sharpening angle needs to be 20 - 30 degrees in total. 

 When it comes to the angle of a knife, the lower the angle, the sharper the blade and while Western blades (typically German manufactured) have a larger angle and therefore a thicker edge, Japanese knives have much thinner angles for a sharper edge which means more care needs to be taken when sharpening these fine angle knives. 

 If you are unsure of what angle you need to sharpen your Japanese knife with, then we are not only going to cover how you can sharpen the perfect edge in this article but also how you can do it consistently without needing to be a professional sharpener! 

Table of content

Correct Japanese Knife Sharpening Angle

For this article, we will assume that your Japanese knife is a standard chef’s knife. As there is such a range of knives for different cutting tasks (meat, bone joints, fish, filleting, fruit, and vegetables..) the angle of the bevel will vary drastically. 

The standard Japanese chef’s knife is by far the most common knife used and the correct sharpening angle for these knives is between 30 - 40 degrees. 

We touched on this earlier but this degree is for both sides of the knife (bevel) combined. Most common knives are Western-inspired when it comes to the edge and are double bevelled meaning that the edge on either side of the blade is symmetrically creating a V edge. Therefore a 15-degree bevel on one side will mean that the sharpening angle for your knife is 30 degrees overall. 

This is because both sides need to be sharpened to the same angle in order to maintain the fine edge. The exception to this is a single bevel knife. 

With a single bevel knife (commonly used with traditional Japanese knives), one side of the blade is actually flat, this means that the single bevel side with a 15-degree angle will give a total sharpening angle of 15 degrees. This is an incredibly fine and sharp angle and with these knives, you will only sharpen the side with the bevel. 

Traditional Japanese Knives will commonly have a single bevel edge however those that are manufactured by the Japanese for the Western world will have a double bevel edge which is why we use this as the baseline to work from. 

If possible, we’d recommend referring to your exact product online (or if you kept the initial manual that came with the knife) to find the angle that it was machined to. If you can’t find this then don’t worry, you can still work out a good estimation for the angle and create a new one.   

How to Sharpen a Japanese Knife at the Correct Angle

Unless you are a master chef or have significant kitchen experience, it’s highly unlikely that you have the level of skill, accuracy, and precision required to sharpen a Japanese knife at a consistent and correct angle. 

When you take into consideration the level of attention and precision that goes into designing and creating a Japanese knife (a tradition of constant improvement with a focus on satisfying all the human senses), then it becomes easier to understand that you can’t take the sharpening process lightly. 

Sharpening a Japanese knife is an art form in itself and to get started with the correct angle we would always recommend that you first find out what angle you need to cut at in order to maintain the edge and secondly select something that can act as a guide. 

Finding the Correct Sharpening Angle

Finding the correct sharpening angle can be quite tricky. If you have the manufacturer’s instructions or know the knife model then it’s going to be easy as you can just look up the manufactured angle and use this for reference. 

If however, you don’t have this then you can use a laser (or normal) protractor to try and determine the angle. This could be a little tricky as the duller an edge gets, the more it will distort the angle measurement. 

For most Japanese knives, a safe option is therefore to choose and angle between 15 - 20 degrees and use this to create your own 30 - 40-degree edge. 

** remember, the angle of one side's bevel is not the edge angle, therefore if you want a 30-degree edge you will need to sharpen each side to 15 degrees.

You can also lie the blade as close to the tapered bevel as possible to replicate this original edge. 

Use a Sharpening Guide

If you are skilled enough to maintain an angle by hand then this is excellent, for most people, however, an initial guide is useful in order to set your angle and have a visual guide. The most common way that people used this is through coins. 

A 90-degree angle is when the knife edge is facing directly down, if you tilt the knife to create a 45-degree angle then most people can do this just by eye and. 

When you need to work with a typical 15-degree angle for a Japanese knife, however, then this becomes much more difficult for most people to measure just by eye alone and this is where coins are useful. 

Two coins stacked on top of each other can typically add up to a 15-degree angle and this is therefore where you would position the back of the knife to set your angle. Using the coins gives a very easy, yet reliable method for sharpening a consistent angle on a Japanese knife yourself. 

This would still be a rough estimate even when using coins and therefore to get the most accurate measurement we’d recommend measuring the angle needed, determining the distance that this would create from the spine of the blade to the whetstone (sharpening tool), and then using coins to fill in that required distance.  

Alternatively you could use a fixed Angle guide like in this image, one is included with every Whetstone Sharpening Stones by default.

What to Use for Knife Sharpening 

The best method for sharpening a Japanese knife is to use a whetstone, these are the traditional methods used to sharpen a Japanese knife and it’s an incredibly satisfying experience to use one, particularly if you are new to knife sharpening. 

Whetstones come in a variety of grades which are determined by the coarseness of the stone. These can range from #200 grit which is needed to reform and edge from a dull blade right the way through to a grit grade of #8000 which is ultrafine and used for precise refining and polishing of the edge. 

Most Japanese knives will mostly need a grit grade of #200 - #3000 when sharpening an angle though this will depend entirely upon how dull your current knife is.  

Round-Up

The correct sharpening angle for a Japanese knife will vary slightly however that majority will need to be sharpened at 30 - 40 degrees. The important thing to remember is that the sharpening angle is the entire angle taking into consideration the bevel angle on both sides of the blade. 

The smaller the angle, the sharper the edge and while it might be tempting to try to sharpen a knife to a fine angle, it’s not recommended. Most Japanese knives strike a balance of strong, tough, and sharp edges, this is through years of honing their craft and combining ancient metalwork knowledge with cutting edge technology. 

This is the reason why Japanese knives are seen as the highest quality and a 30 - 40-degree angle for the edge helps to set this standard. 




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