When shopping for Japanese high carbon steel knives, you’re bound to come across the two main types of steel: Shirogami and Aogami. Both types of steel are excellent for knife making, but there are some critical differences between them. Shirogami is what most refer to as white steel, while Aogami is the coveted blue paper steel.
The main difference between Shirogami vs. Aogami is that Shirogami can be sharpened to a razor-sharp edge but is more brittle and susceptible to rust. In contrast, Aogami is harder and more corrosion-resistant but tougher to sharpen. Another difference is that blue steel contains chromium (Cr) and tungsten (W).
This article will discuss all you need to know about the differences between Shirogami and Aogami. We’ll also look at the similarities of each steel, compare their features and characteristics, and give a final verdict on which one is better for you.
Shirogami (white steel)
Shirogami is a Japanese high carbon steel knife with the least amount of impurities in the form of Sulfur (S) and Phosphorus (P). The main ingredients are Carbon (C) (up to 2.7%) and Iron (Fe).
The name white paper steel results from the white paper manufacturers used when wrapping the blade after forging. As the purest form of high carbon steel, most chefs hold it in high regard as the best steel for making knives.
While it’s debatable whether it’s the best steel, there’s no doubt that Shirogami is of excellent quality. Sharpening the knife gives it a perfect mirror-like finish, and the edge retention is incredible. A nice finish with a fine whetstone grit can last you long before needing a touch-up. It’s not uncommon for a Shirogami knife to retain its edge for months with proper care and maintenance.
The main downside of Shirogami is that it’s quite brittle, making it susceptible to chipping and breaking. Shri-ko knives are pretty reactive and will rust or corrode when exposed to extreme conditions. However, the natural formation of a carbon steel patina can help protect the blade from rust.
Different variations of Shirogami exist. The main difference between them is the amount of carbon in the steel.
Shirogami#1 contains around 1.25–1.35% of carbon (C). It’s the hardest form of high-carbon steel but also the most brittle. It rates at 61–64 HRC on the Rockwell hardness scale.
This steel is an excellent choice for making razors and other fine-cutting tools. Due to its brittle nature, it’s not the best choice, especially when cutting through hard objects such as bones or frozen food.
Shirogami #2 has slightly less carbon than Shirogami #1. It contains around 1.05–1.15% of carbon (C) and rates at 60–63 HRC on the Rockwell hardness scale. Shirogami #2 isn’t as hard as Shirogami #1, but it’s less brittle.
It boasts excellent edge retention and can be honed to a razor-like edge; as such, most manufacturers use it in the manufacture of Japanese kitchen knives. The perfect example of a Shirogami #2 steel knives are the Japanese Nakiri knife.
Shirogami #3 is the softest form of Shirogami steel, with only 0.80–0.90% of carbon (C). It rates at 58–61 HRC on the Rockwell hardness scale. Shirogami #3 is softer than the other two types of steel, making it more ductile. The main advantage of this steel is that it’s less likely to chip or break; however, it doesn’t hold its edge as well as the harder steel.
Features of shirogami steel
Some of the main features of Shirogami steel include:
- High carbon steel with the least impurities
- It can be sharpened to a razor-like edge
- Highly reactive and will rust and corrode quickly
- Brittle and susceptible to chipping due to low toughness
Aogami (blue steel)
Aogami, also known as blue paper steel, is a Japanese high carbon tool steel. Apart from phosphorus (P) and sulfur (S), it also has tungsten (W) and chromium (Cr). Tungsten and Chromium aren’t impurities but are added to increase durability and resistance to corrosion.
Tungsten makes Aogami relatively harder to sharpen; as such only pro blacksmiths have the skills to sharpen it to a fine edge. Otherwise, the blade may crack or break if not handled correctly.
Aogami is also reactive steel that will rust and corrode when placed in extreme conditions. However, the chromium in the steel prevents it from rusting as quickly as Shirogami. The additional elements also ensure the blade holds its edge longer than the Shirogami.
Like Shirogami, different types of Aogami exist. Below is a list of the three main types:
Aogami #1 is a high-carbon steel with 1.2–1.4% carbon (C). It rates at 64–65 HRC on the Rockwell hardness scale. Aogami #1 is as hard as Shirogami but not as brittle. In addition, it has excellent edge retention and stays sharp for longer. However, the steel is not as common as the other two types of Aogami.
Aogami #2 is the most popular type of Aogami. It contains about 1.0–1.2% of carbon (C) and rates at 6–64 HRC on the Rockwell hardness scale. The main advantage of Aogami #2 is that it’s easy to sharpen and doesn’t chip as easily as Aogami #1. It’s also the most durable type of Aogami.
Aogami super (super blue)
As the name suggests, Aogami Super is the hardest type of Aogami. It contains about 1.45% carbon (C) and rates 65–67 HRC on the Rockwell hardness scale. Super blue also has Vanadium, an element not found in the other types of Aogami.
The additional element gives it superior wear resistance. It holds its edge the longest but is also the most difficult to sharpen. Moreover, Aogami super also contains molybdenum which makes it cool in either oil or water during the heat-treating process.
Features of Aogami steel
Some of the key features of Aogami include:
- High carbon steel with additional tungsten, chromium, vanadium, and molybdenum
- It’s quite hard to sharpen due to the additional tungsten
- It contains chromium which makes it more resistant to corrosion
- It has excellent edge retention
Shirogami vs. Aogami
Comparing Shirogami and Aogami involves looking at the similarities and differences between the two types of steel. Below is how the two types of steel compare:
- Both are Japanese high carbon steel: High carbon steel essentially means that the steel has a carbon content of more than 0.6%. The carbon gives the steel its hardness, increases wear resistance, and ensures it stays sharper for longer.
- Both are used to manufacture Japanese kitchen knives: Shirogami and Aogami are two of the most popular types of steel used in Japanese kitchen knives.
- They’re both suitable for professional chefs: The high carbon content in both types of steel makes them ideal for professional chefs. Carbon is the main element that gives knives their hardness.
- Both types of steel are reactive: Shirogami and Aogami are reactive steels, meaning they will corrode when exposed to extreme conditions such as moisture or salt. As such, they require special carbon steel care to prevent them from rusting.
- Shirogami is purer: Shirogami has less impurities than Aogami. The main impurities in Shirogami are phosphorus (P) and sulfur (S).
- Aogami contains tungsten and chromium, whereas Augami doesn’t: In addition to phosphorus and sulfur, Aogami also contains tungsten (W) and chromium (Cr). Tungsten and chromium are added to increase the durability and resistance to corrosion of the steel.
- Shirogami is more brittle: Shirogami is more brittle than Aogami. The additional elements in Aogami make it more durable and less likely to break or crack.
- Aogami is harder to sharpen: The additional elements in Aogami make it more difficult to sharpen. However, the steel also holds its edge for longer as a result.
- Aogami is more expensive: Because of the additional elements, Aogami is more expensive than Shirogami. Most expensive Japanese kitchen knives are made from Aogami steel.
- Aogami holds its edge better: The additional elements in Aogami make the steel more wear-resistant. As a result, it holds its edge for longer than Shirogami.
- Shirogami becomes sharper than Aogami: With the right sharpening technique, Shirogami can become sharper than Aogami. However, the edge won’t last as long as Aogami.
|Shirogami has fewer impurities (phosphorus and sulfur)||Aogami has more impurities including phosphorus and sulfur alongside other elements such as chromium and tungsten|
|Shirogami can be sharpened to a razor sharp edge but doesn’t its edge for long||Aogami is harder and doesn’t becomes very sharp but retains its edge for long|
|Shirogami does not contain chromium which makes it more susceptible to rust and corrosion||Aogami contains some of amounts chromium which reduce the chances of corrosion|
|Shirogami is easier to sharpen||Aogami is harder to sharpen|
|Shirogami is more brittle and will chip or break when used on hard cartilage||Aogami is highly durable because of the additional tungsten|
Which steel should you choose for your kitchen?
When choosing between Shirogami and Aogami, it’s important to consider your needs as a chef. If you’re looking for a knife with excellent edge retention, then Aogami is better. However, if you’re looking for a knife that’s easier to sharpen and becomes razor sharp, Shirogami is better.
In general, Aogami steel is better for professional chefs who want a durable knife that will last longer. Shirogami steel is better for home cooks who are willing to sharpen their knives more often.
When comparing Shirogami and Aogami, there’s no universally accepted standard that states either type is better than the other. It ultimately comes down to your preferences as a chef.
Shirogami vs. Aogami (FAQs)
Understanding the differences between Shirogani and Aogami is the first step in finding the right type of steel for your kitchen knives. Shirogami is more brittle and harder to sharpen but becomes sharper than Aogami. On the other hand, Aogami is more expensive and difficult to sharpen but holds its edge better. Ultimately, the decision of which type of steel to choose comes down to your preferences as a chef.
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