Japanese Knife Sharpening Stone: Yes, You Too Can Know All About These Mysterious Whetstones

Japan has so many good sharpening stones like… 

King toishi, shapton hanokuromaku, Naniwa sharpening stone, Kensho, etc..

In this article,

We will talk about these Japanese knife sharpening stones in detail.

Check it out…

1. Your knife is something like the Millennium Falcon

Even though it is old,

If you take good care of it, it will still have great performance.

You found the right article.

Because I am the Chewbacca of the kitchen knife world.

2. What is your favorite whetstone series?

In 2003, at Homecenter Kohnan, I bought my first whetstone. It was a sweltering summer day.

My first santoku knife was dull, so I wanted to do something about it. It has been 3 months since I started living by myself. 

There was no longer my dad to sharpen the kitchen knives. 

Have you ever had this kind of experience where you felt you were grown up because you could do certain things? 

It was exciting. Right?

3. Solidifying methods are important

A whetstone is made of abrasive particles and binder materials.

Important:

The binder materials help retain the abrasive particles together.

There are 3 standard solidifying methods to make whetstones.

Firing up in high heat to solidify (over 1000C),

Firing up in relatively lower temperature to solidify(around 200C),

And drying to solidify.

4. Examples of vitrified whetstones are…

“King Toishi” and “King Deluxe” by Matsunaga Toishi

“Gouken Deluxe” and “Gouken Pro” By Naniwa Toishi

“Kensho Itadaki” by Kensho

These vitrified whetstones have high grinding power.

5. Vitrified whetstones are solidified by firing up in over 1000C (1832F)

It is made of abrasives and feldspar or soluble clay.

First, you make the whetstone shape by press forming, then drying it out.

After that, solidify it by sintering it at a high temperature.

It is usually 600C to 1300C.

This solidify method is used very often when the abrasive is green carbon(GC).

Vitrified whetstones are also called ceramic whetstones. Because…

The manufacturing process is the same as baking pottery.

6. Vitrified whetstones have high grinding power and low polishing ability

Pros of vitrified whetstones are high grinding power and durability.

Vitrified method has strong bonds to keep abrasives tight.

So this whetstone is hard and has a high grinding power, 

And it is not easily deformed.

Cons of vitrified whetstones are soaking time and lack of elasticity.

You need to soak a vitrified whetstone for a long time before you use it.

As I said, it is hard, so it doesn’t have as much elasticity as other types of whetstone.

The surface of the blade tends to be little rough,

Don’t use a vitrified whetstone if you need to do some delicate job.

I recommend having this for…

Coarse stone (#80 – #320) and medium stone (#400 – #2000)

7. Examples of resinoid whetstone are…

“King G1” and “King S1” by Matsunaga Toishi

“Ebi Super”and “Gouken Kagayaki” by Naniwa Toishi

“Kitayama” and ”Arashiyama” by Ohtani Toishi

“Kensho Sei series” by Kensho

Usually, they have low grinding power, but polishing ability is very high.

So they are good for erasing scratches for the finishing phase.

8. Resinoid whetstones are solidified by firing up in 200C(392F)

This is made of abrasives and binder as phenol resin, epoxy resin, or polyamide resin.

These thermosetting resins solidify by heat.

Resinoid whetstones don’t have grind power as much as vitrified whetstones.

So these whetstones are often used for finishing.

It is a popular type for fine whetstones (#3000 –).

9. Resinoid whetstones have low grinding power, and high polishing ability

Pros of resinoid whetstones are elasticity and thoroughness.

A risinoid whetstone makes your knife blade really smooth.

Especially when you use a fine resinoid whetstone,

It makes a beautiful mirror polished blade.

You don’t need to soak in the water before using this type of whetstone.

You just need to sprinkle some water while you use it.

Cons of resinoid whetstones are low grinding power and less durability

Resinoid whetstones have low grinding power. This is because binder resin in these stones have elasticity.

It is a good thing if you want to do delicate sharpening, but…

If you want to shave the blade a lot, it will be the downside.

Resinoid whetstones are softer than other whetstones.

So it gets worn out faster than other stones.

In addition, you shouldn’t soak it in water for a long time.

It will cause deterioration of the stone.

10. Examples of magnesia whetstones are…

“Ha No Kuromaku” by Shapton

Magnesia whetstones have a good balance of grinding power and polishing ability.

11. Magnesia whetstones are solidified by drying

This is made of abrasives and cement like magnesia oxychloride.

After kneading them, you make a shape of a whetstone and dry it.

Pros of magnesia whetstones are usability and grinding power.

You don’t need to soak this kind of whetstone in water.

Magnesia whetstones have a good amount of grinding power.

In terms of grinding power, it comes next to vitrified whetstones.

Magnesia whetstones have large varieties of finesse.

From coarse whetstones to fine whetstones.

It also gives your knife a smooth feeling when you use it.

A con of magnesia whetstones is degradation over time

This is because magnesia whetstones are not sintered during the production process.

It might have cracks if you use it for a long time.