Aogami steel and Shirogami steel are the main types of Japanese steel. They are used to make the best kitchen knives on the market, but there are major differences between them. Aogami is blue paper steel, while Shirogami is white paper steel. The white and blue names result from the paper used to wrap the blades after forging.
The main difference between Aogami and Shirogami is the chemical composition and carbon content. Aogami contains more carbon and has Tungsten and Chromium, making it harder and more corrosion resistant. In contrast, Shirogami is easier to sharpen and more susceptible to rust because it has less carbon and does not contain added elements.
Brief History of Aogami and Shirogami steels
The history of Japanese steel in knife making dates back to the Edo period (1603-1868), where traditional Japanese blacksmiths developed various types of high-carbon steel for various cutting tools.
One of the main factors that made Japanese knives famous for their quality is the use of steel with high carbon content, which gave them their sharp edge, durability, and resistance to corrosion.
Over the years, the blacksmiths continued to refine the steel-making process, resulting in the development of the two main types of Japanese steel – Aogami and Shirogami. Aogami, also known as blue steel, is high-carbon steel with added Chromium and Tungsten, making it harder and more resistant to corrosion.
Shirogami, also known as white steel, is traditional Japanese steel with high carbon content, but it is more susceptible to corrosion and requires regular maintenance to prevent rust.
Different types of Aogami and Shirogami steel are used to make different types of kitchen knives, with each type having a specific carbon content and hardness level, resulting in different properties, such as sharpness, edge retention, and durability.
For example, Aogami #1 is used to make sushi knives, while Aogami #2 is used to make all-purpose kitchen knives. Shirogami #1 is used to make sushi knives, while Shirogami #2 is used to make Nakiri knives.
What is Aogami Steel?
Aogami, also called blue steel, is high carbon steel with very few impurities like Phosphorous and Sulphur. It also contains Chromium which increases its corrosion resistance and Tungsten which makes it harder and more durable.
Because of the increased hardness, blue steel is difficult to sharpen. Only knife users and blacksmiths with excellent sharpening skills can attain a razor-sharp edge with Aogami knives. The good news is, because of the added elements, Aogami can hold a sharp edge for a very long time, so you do not have to sharpen your knives every often.
Types of Aogami Steel
There are various types of Aogami Steel whose main difference is the amount of carbon in the composition. These include Aogami #1, Aogami #2 and Aogami Super.
Aogami #1 is high-carbon steel, which contains 1.2-1.4% Carbon in its chemical composition and has a hardness of 63-65HRC on the Rockwell hardness scale. Aogami #1 blades are dangerously sharp and hold a sharp edge for a long time.
It is mainly used to make sushi knives like Yanagiba. The major downside with this steel is that it is not as common as other variations of Aogami.
Aogami #2 contains 1.0-1.2% Carbon with a hardness of 64-65 HRC, and it is the most popular Aogami variation. It is easier to sharpen and more durable than Aogami #1 because it contains more Tungsten in its composition.
Because of its properties, Aogami #2 is used to make all-purpose knives like the gyuto knife.
Aogami Super, also known as the super blue, is the hardest variation of Aogami knife steel. It contains 1.45% Carbon and has a hardness of 65-67 HRC.
The major difference between Aogami super and other Aogami types is that it contains Vanadium which contributes to the super hardness and gives it excellent wear resistance and edge retention. However, it is the most challenging to sharpen.
Moreover, super blue can be cooled in water and oil because it contains molybdenum in its composition. The properties of Aogami super make it premium steel, making it more expensive than the three.
What is Shirogami Steel?
Shirogami, also called white steel, is traditional Japanese steel with very high amounts of carbon and very few impurities. Although Aogami steel is the latest developed Japanese knife steel, knife makers and users still seek Shirogami steel because it is the purest form of high-carbon steel with excellent properties.
Shirogami steel attains a razor-sharp edge with simple sharpening tools like a whetstone. Moreover, the blade remains sharp for a very long time.
On the downside, Shirogami steel does not contain Chromium and Tungsten, which makes it highly reactive and brittle compared to Aogami steel. However, as the blades corrode, they form a patina, a natural protective layer that prevents further oxidation.
Types of Shirogami Steel
There are various types of Shirogami Steel whose main difference is the amount of carbon in the composition. These include Shirogami #1, Shirogami #2 and Shirogami #3.
Shirogami #1 is the hardest type of Shirogami which contains 1.25-1.35% carbon and has a hardness of 61-64 HRC on the Rockwell hardness scale. Knives made from Shirogami #1 are very sharp but very brittle. They easily break and crack when used for challenging applications like handling bones or cutting cartilage.
Shirogami #1 steel is used in the knife industry to make sushi knives and in other industries to make good cutting tools like razors.
Shirogami #2 is the most common white steel and contains around 1.05-1.15% Carbon with a hardness of 60-63 HRC on the Rockwell hardness scale. The blades of Shirogami #2 attain a razor-sharp edge very fast, hold an edge for a long time, and are more durable than Shirogami #1.
White steel #2 is mainly used to make Japanese kitchen knives like the Nakiri knife.
Shirogami #3 contains 0.8-0.9 % carbon, the lowest carbon content of the three. It offers a hardness of 58-61 HRC on the Rockwell hardness scale. It does not provide good edge retention but is the toughest, meaning it does not break or chip easily when used in tough applications.
|Steel Type||Chemical Composition||Hardness (HRC)||Corrosion Resistance||Edge Retention||Ease of Sharpening|
|Aogami #1||High-carbon (1.2-1.4% Carbon), Chromium, Tungsten||63-65||High||High||Difficult|
|Aogami #2||High-carbon (1.0-1.2% Carbon), Tungsten||64-65||Medium||High||Easier|
|Aogami Super||High-carbon (1.45% Carbon), Chromium, Tungsten, Vanadium, Molybdenum||65-67||High||High||Most challenging|
|Shirogami #1||High-carbon (1.25-1.35% Carbon)||61-64||Low||High||Easy|
|Shirogami #2||High-carbon (1.05-1.15% Carbon)||60-63||Low||High||Easy|
|Shirogami #3||Low-carbon (0.8-0.9% Carbon)||58-61||Low||Low||Easy|
Major Similarities between Shirogami and Aogami
- They are both Japanese high-carbon steel manufactured by Hitachi. co
- Both have dangerous sharp blades with excellent edge retention
- They are both used to make Japanese kitchen knives
- Both are ideal for professional chefs because the high carbon element gives the knives superior hardness and durability.
- They have poor corrosion resistance and are, therefore, highly susceptible to rusting when exposed to corrosive environments. As a result, they require proper care and maintenance to prevent them from rusting.
Major Differences between Shirogami and Aogami
- Shirogami steel contains fewer impurities than Aogami.
- Aogami steel contains Chromium and Tungsten, whereas Shirogami does not
- Shirogami is more brittle because it does not have Tungsten which increases steel durability
- Aogami steel is more difficult to sharpen than Shirogami steel because of the added elements
- Aogami offers better edge retention than Shirogami steel, which is attributed to the added Chromium and Tungsten
- Shirogami steel is easier to sharpen than Aogami because it contains less carbon which makes it soft
- Aogami steel knives are more expensive than Shirogami knives
Is Aogami or Shirogami better?
Aogami and Shirogami are both high-quality knife steels that excel in different properties. Aogami steel is durable, offers excellent edge retention, and is more resistant to corrosion. On the other hand, Shirogami steel is very sharp, less brittle, and easier to sharpen.
Choosing between the two requires you to consider your knife needs. If you are looking for durable knives that do not require frequent sharpening, consider Aogami knives. On the other hand, if you want very sharp and less brittle knives and do not mind frequent sharpening, the Shirogami steel options are ideal for you.