Features of Sakai, Japanese Kitchen Knives
Japanese knives are made by combining two different materials, they have both durability and sharpness. Some of them have unique patterns due to their structure such as Damascus. Their functionality and beauty are valued all over the world.
Stainless steel is generally any type of steel alloy that has a minimum of 10.5% Chromium content by mass. Compared to Carbon steel knives, stainless steel knives are highly resistant to corrosion. These are a great general purpose knife and a good starting point for a collection.
An important note is that stainless steel knives are not completely 'stain-proof' or 'rust-proof'. If they are exposed to water for a prolonged amount of time they will rust, in particular if the liquid has salt in it.
Common Stainless Steel variants are VG-10, AUS-10, and Silver-3 (aka Ginsan).
VG-10 is a grade of stainless steel produced in Japan primarily focused on cutlery. The name stands for V Gold 10 where "gold" refers to the quality. The approximate content is Carbon: 1%, Vanadium: .1-.3%, Chromium: 14.5-15.5%, Molybdenum: .9-1.2%, Cobalt: 1.3-1.5%, Manganese: .5%, and Phosphorus: .03%.
This steel has good edge retention and has very good corrosion resistance. In Damascus style knives it is often used as the core, with the Damascus steel wrapped around.
This steel is about 1.05% of carbon, 14% of chromium, 0.2% of molybdenum, 0.2% of vanadium, 0.5% of manganese, 0.5% of nickel, 1% of silicon and hardness 58-61 HRC. Molybdenum / vanadium is added to ordinary stainless steel, and the hardness is strengthened more than the basic stainless steel. It is a high-performance knife using a sharp and rust-resistant AUS-10 as a core material.
This steel is about 0.95-1.1% of carbon, 13-14.5% of chromium, 0.6-1.0% of manganese, 0.5% of nickel, 0.35% of silicon and hardness 59 HRC.
Bohler-Uddeholm is a large Austrian company manufactures the steel used in the Grand Chef knife series. Established in 1670 in Sweden, they have a long history more than 300 years. Since quality iron ore excavated from company mines contain an extremely low amount of phosphorus and sulfur, the special steel is reputed to exceptional sharpness and abrasion and corrosion resistance for many years of service. Grand Chef is a registered trademark in Japan.
Damascus steel is a beautifully patterned steel material that was originally produced in the Damascus region of Syria since it was said to be called warts steel. The current Damascus steel produces an elegant ripple to alternately superimpose and polish two kinds of steel materials.
Often times the Damascus steel is wrapped around a core metal such as VG-10, AUS-10, Silver-3, or high-carbon steel to give the knife additional qualities, whether that be functional or aesthetic.
Yasugi steel or Yasugi hagane produced by Hitachi Metals Ltd in the Shimane prefecture, within Japan. Since ancient eras top quality iron sand has been produced for creating traditional Japanese swords in this region. There are 3 main top grade high carbon steels such as Shirogami or White Steel (#1, #2), Aogami or Blue Steel (#1, #2) and Aogami Super or Blue Super Steel.
Yasugi steel is high-grade cutting steel with a high purity. A high level of craftsmanship is required for this steel which is hard to handle and form. As such generally only master craftsmen handle this type of metal when making Japanese Knives.
While Yasugi steel allows for a razor sharp edge, often used in to make swords in ancient times, it is also a rusting steel. Thus it requires more care and maintenance than other types of steel. On the other hand, Damascus steel and molybdenum steel are of a kind called rust-free steel material, stainless steel.
Shirogami #1, Shiroichiko or White Steel #1
Shirogami #1 has a higher carbon content than Shirogami #2. The higher the carbon content the better a knife holds an edge, however it also becomes more brittle. About 1.2-1.4% Carbon, 0.25% Manganese, and a practical hardness of 61 to 64 HRC. Very hard steel material made of pure carbon steel with fine grained carbon with very few contaminates within the iron. It is used in the manufacture of Honyaki knives by the traditional smith making process. There are only few knife craftsmen who can give the real value of this steel material even in Sakai, so the kitchen knife of Shirogami has become a very rare kitchen knife with value. These knives can be sharpened to a razor's edge. For practical purposes, many sushi chef's will choose Shirogami #2 (White Steel #2) as it is less brittle and less likely to chip than it's higher carbon counterpart.
Shirogami #2, Shironiko or White Steel #2
While the composition of Shirogami #2 (White Steel #2) is virtually the same as Shirogami #1, the carbon content is slightly less (1.0-1.2% Carbon). This allows the knife to be less prone to chipping and is generally preferred by most chef's given the option of White Steel knives. Both White Steel #1 & #2 allow chef's to make very fine, particular cuts of fish, vegetables, and garnish.
Aogami #1, Aoichiko or Blue Steel #1
Aogami vs Shirogami - Aogami or Blue Steel #1 has about 1.3% carbon, 0.4% chromium are added to the basic white paper (Shirogami). It has a practical hardness of 61 to 64 HRC. It is a high grade steel which strengthened the heat treatment characteristics and wear resistance by adding chromium and tungsten to white steel. The sharpness lasts longer and it cuts smoothly, so the cut is finished clean.
Aogami or Blue Steel #1 has the same carbon content as Shirogami / White Steel #1, the difference is the additional of the tungsten and chromium to the material. These additions add specific qualities to an already high quality steel.
Aogami #2, Aoniko or Blue Steel #2
Aogami or Blue Steel #2 has the same composition as the Blue Steel #1, but its hardness is lower due to a lower carbon content (the same as White Steel #2 at 1.0-1.2% Carbon). In addition to the elements that make up Blue Steel #1, tungsten and chromium are added to increase the durability and abrasion resistance. Generally speaking, the differences between Aogami or Blue Steel and Shirogami or White Steel, is that it is harder to break and the sharpness lasts longer. Additionally, it is said that Shirogami or White Steel is easier to sharpen compared to Aogami or Blue Steel.
Knife Material Composition
If you would like to dive into the world of material composition we would recommend going to the source, Hitachi Metals. You will need to go to the YSS drop down and then scroll all the way to the bottom to find the Shirogami and Aogami. This is a great way to compare Shirogami vs Aogami.
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