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Shapton Kuromaku Vs. Glass Stone: What Works Best?

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Knife sharpening is a cause for many controversies and results in much debate among knife makers and knife owners about sharpening methods and tools. Everybody has their own preferred method and tools that they would recommend over others.

There is no sharpening method that causes more debate than stone sharpening, and in this category, the Shapton company has traditional stone products and glass stones. If we compare the Shapton Kuromaku with their glass stones, which would work the best?

Shapton Kuromaku stones and the glass stones both sharpen knives from 57 HRC to 62 HRC equally well. For knives that have steel hardened above 62 HRC, the glass stones are superior and perform better than the Kuromaku stones. The glass stones are also more durable and outlast the Kuromaku stones.

Shapton is a company that sells high-quality knife sharpening equipment for a variety of sharpening tasks for the knifemaker or knife owner. Glass stones are an innovation that is a possible choice as a knife sharpening medium over the traditional stone versions, but how do the glass stones stack up against the traditional stones?

If you are interested in checking out the best whetstones for your knives we recommend and use you can find them by clicking here (Amazon link).

What Is The Shapton Kuromaku?

Shapton Kuromaku with Holder
Shapton Kuromaku with Holder (source)

Shapton is a company that manufactures quality knife sharpening stones. Their Kuromaku is a set of Waterstones that are color-coded according to the grit of the stone.

While these stones are intended to be used with water, they can also be used with oil as a lubricant.

These are traditional Waterstones that are very hard and very flat and are considered to be high-quality sharpening stones.

These stones are not natural stones but are commercially manufactured stones made from a variety of abrasive materials, including ceramics.

If you are interested in buying Kuromaku whetstones made by Shapton you can find them by clicking here (Amazon link).

What Is The Shapton Glass Stone?

Shapton Glass Stone with Field Holder
Shapton Glass Stone with Field Holder (source)

The Shapton Glass stones differ from the Kuromaku version in the material that the stones are made from. The glass stones are made from a ceramic material that is mounted on a base of tempered glass.

The advantage of ceramic stones backed with glass is that the stones can be made thinner and lighter. These ceramic stones are very flat, hardwearing, and last a long time.

If you are interested in buying Glass stones made by Shapton you can find them by clicking here (Amazon link).

Shapton Kuromaku vs. Glass Stone: Which Works Better?

The Shapton Kuromaku and the Shapton glass stones may come from the same manufacturer, but they have different characteristics that make for some differences between the two versions.

Both stones come in a range of grits which make them suitable for a wide range of sharpening tasks, from re-establishing an edge to honing an edge bevel to a mirror-like shine and razor-like sharpness.

Even though the Kuromaku is a very hard stone and well-made, the glass stones are much more resistant to wear between these two stones.

The Kuromaku will still last you a long time, approximately 4 to 5-years, depending on the frequency of use, but the glass stones could last substantially longer due to their greater durability.

Both sets of stones do not require pre-soaking in water before using them. With the Kuromaku stones, however, it is recommended that they are soaked for between 5 and 6 minutes before you use them for the first time since they may have dried out in storage or en-route before you received them.

The glass stones, in contrast, are true splash-and-go stones. These glass stones do not need to be soaked at all but only need to be sprinkled with water as you use them.

Neither of these stones needs to be ponded or used in a basin, where they are constantly in water. This makes both Shapton stones fairly portable as a sharpening method.

TIP: If you do not want to use whetstones alone you can try using sharpening systems that guide you through the sharpening process. Check the best sharpening systems in the article below:
Ultimate Guide: Best Knife Sharpening Systems for Beginners

How Do These Stones Sharpen?

The most important factor to consider between two different types of sharpening stones would be the end result. But this is not the only important factor that needs to be considered.

Other aspects can impact the sharpening process and affect how the person doing the sharpening reacts to the ‘feel’ of the stones.

The general consensus with these two types of sharpening stones is that the end result on the blade is very similar. The level of sharpness produces by both versions is very sharp and comparable to each other.

Where the two stones differ is in the tactile feedback that they give to the person doing the sharpening. The process of sharpening a knife relies very much on the way the blade feels on the stone and the way that this feeling changes during the sharpening process.

The glass stones provide better tactile feedback to the user, which gives a person a greater feel for what is happening to the blade and allows you to adjust your technique appropriately.

Another difference between the two types of stones is how effective they perform on knives of different hardness levels.

The Kuromaku stones do well on steels that range between 57 to 62 HRC, which is pretty hard steel. However, when the HRC level of the steel gets above the 62 mark, the stones do not perform as well and seem to wear substantially faster.

The glass stones, on the other hand, can easily be used to sharpen steels of 57 HRC all the way up to 66 HRC while losing very little in the way of performance with these harder steels and also displaying less wear.

The speed at which these stones sharpen, which is measured in the number of strokes of the blade across the surface of the stone to achieve an edge, are comparable.

This means that with a knife that is between 57 to 62 HRC, the stones would provide the same level of sharpness with the same number of passes over the stones.

Once the hardness of the steel is above the 62 HRC mark, the glass stones quickly out-perform the Kuromaku stones.

The downside with the glass stones is their price; they are consistently between 30 to 40% more expensive than the Kuromaku stones.

For the knife owner, it would therefore make more sense to purchase Kuromaku stones rather than the glass stones if you do not need to sharpen knives that are harder than 62 HRC.

TIP: A lot of people are afraid of sharpening their knives. Do you know what steels are easiest to sharpen? Check them out in the article below:
List of The Easiest Knife Steels To Sharpen (With Examples)

Shapton Kuromaku vs. Glass Stone: The Main Differences

Shapton Kuromaku Vs. Glass Stone
Shapton Kuromaku vs. Glass Stone: The Main Differences

To summarize the differences between these two sharpening stones, we have placed their main characteristics in a table, side by side, for easy comparison. This should make your choice easier when selecting the right type of stone for the types of knives that you own.

FeatureShapton KuromakuShapton Glass Stones
DurabilityThe Kuromaku is a good stone that is durable and will last 4 to 5 years.The glass stones are more durable and will last longer than the Kuromaku stones.
Tactile feedbackTactile feedback is acceptable.Tactile feedback is superior to the Kuromako stones.
Hard steel capabilityDoes well with steel from 57 HRC to 62 HRC, but not beyond.The glass stones perform well all the way up to knives of 66 HRC
Overall recommendationThese are quality stones that work extremely well up to the recommended Rockwell hardness level and will serve you well.These stones are hard to beat for performance and have an excellent feel when being used. If you sharpen knives beyond 62 HRC, get a set of these stones.

Essentially what this means is that both these sharpening stones perform very well up and do an excellent job of putting an edge on a knife.

The only real reason that you would purchase the glass stones over the Kuromaku stones would be if you regularly sharpen knives that are above 62 HRC.

TIP: Are you looking to buy a new whetstone? Check out our recommendations (we personally use the first three ones):

Our PRO choice whetstones combo (Amazon links):

Our budget choice (Amazon link): Sharp Pebble Extra Large Sharpening Stone Set

Choosing The Right Stone: Shapton Kuromaku Vs. Glass Stone

When it comes to sharpening your knives, choosing the right stone can make a significant difference in the results. The Shapton Kuromaku and Glass Stone offer excellent sharpening capabilities, but each has unique characteristics that may make one more suitable for you than the other.

Here are some factors to consider when choosing between these two stones.

  • Type of Knives You Own. The hardness of your knives’ steel is a crucial factor to consider. If your knives have a 57 to 62 HRC hardness level, both the Kuromaku and Glass Stone will serve you well. However, if you have knives with a hardness level above 62 HRC, the Glass Stone would be a better choice due to its superior performance and durability with harder steels.
  • Your Skill Level. If you’re a beginner, you might find the Kuromaku stones more approachable due to their traditional design and feel. On the other hand, if you’re an experienced sharpener, you might appreciate the superior tactile feedback and performance of the Glass Stones.
  • Frequency of Use. If you sharpen your knives frequently, the Glass Stone’s superior durability might be a more cost-effective choice in the long run, despite its higher initial cost. If you sharpen your knives less frequently, the Kuromaku stones might be a more economical choice.
  • Budget. The Glass Stones are generally more expensive than the Kuromaku stones. If budget is a significant factor for you, the Kuromaku stones offer excellent performance at a more affordable price point.
  • Portability. Both stones are fairly portable, but the Glass Stones are thinner and lighter, making them slightly more convenient for travel or if you need to move your sharpening setup frequently.

The best stone for you is the one that meets your specific needs and preferences. The Shapton Kuromaku and Glass Stone are both high-quality sharpening tools that help you maintain your knives in top condition. Consider your knives, sharpening skills, frequency of use, budget, and portability needs to make the best choice for your sharpening needs.


Shapton is a Japanese company that is well known for its excellent quality of sharpening stones. They are particularly popular with people who own Japanese kitchen knives.

These knives are generally made from steel that is hardened to a greater HRC than most western made knives, which makes them difficult to sharpen.

The stones from Shapton provide a solution for Japanese knife owners as well as other knife owners in that the stones they provide are fast sharpeners, even on hard steel, and the quality that goes into their manufacture shows in the results they demonstrate on expensive knives.

These stones are not exclusively for the use of owners of Japanese knives and will quickly have your knives hairsplitting sharp in no time!

TIP: If you would like to buy a new Japanese knife you need to be careful because the internet is full of fake Japanese knives. Find out what to watch out for when buying a Japanese knife in the article below:
Spotting FAKE Japanese Knives: 8 Features To Watch Out For