Look into knife steels for long enough and you will run into the name Ginsan. Silver #3, Silver 3, GIN3 — the names vary, but they point to the same steel. Is it stainless, or is it carbon steel? It seems to have a bit of both. Here is an attempt to sort it out, using the manufacturer's published figures.
What Ginsan is
Ginsan is the knife steel that Proterial (formerly Hitachi Metals) sells as GIN3. Proterial's own page describes it as a "stainless steel which has hardness and sharpness comparable to carbon steel." The applications listed are kitchen knives and scissors.
The published composition is 0.95 to 1.10% carbon, 13.00 to 14.50% chromium and 0.60 to 1.00% manganese. Hardness after hardening is HRC 59 or higher. No additions such as molybdenum or vanadium are given in the specification.
Between stainless and carbon
An iron alloy with about 10.5% chromium or more is called stainless steel. According to the Japan Stainless Steel Association, the surface of stainless steel is covered by a passive film only a few nanometers thick, a dense layer made mainly of chromium bound to oxygen. If it is scratched, it re-forms quickly as long as oxygen is present. Ginsan's 13 to 14.5% chromium meets that condition.
Its carbon, on the other hand, is high at about 1%, roughly the same level as carbon steels such as Shirogami and Aogami. More carbon means a harder steel that can hold a keen edge. Ginsan can be described as a steel with a carbon content close to carbon steel, made more resistant to rust by chromium. The phrase "between stainless and carbon" comes from this combination.
Where it sits among Shirogami, Aogami and VG10
Shirogami is a plain high-carbon steel with few impurities, valued for easy sharpening and a keen edge. It contains no chromium and rusts readily. Aogami adds tungsten and chromium to improve wear resistance, but the chromium is small and it is not stainless. VG10 is a stainless steel that adds molybdenum, vanadium and cobalt to chromium, designed to hold its edge through hard carbides.
Ginsan, by contrast, is a stainless steel whose additions stay mostly with chromium, and it is positioned as a steel with a character close to carbon steel.
So which is best? The name of the steel alone cannot answer that. Sharpness and chipping resistance depend not only on hardness but also on blade angle, thickness and heat treatment. We also could not find published data comparing these steels under the same conditions. So we do not rank them here.
Rust resistant, but not rust proof
Ginsan resists rust far better than Shirogami or Aogami. Still, stainless steel is not a steel that never rusts; it is a steel that rusts less. If salt, acid or moisture stays on the blade for long, even Ginsan can rust.
Care is not difficult. Wash the knife soon after use, wipe it with a dry cloth and let it air dry. Be especially careful not to leave it after cutting vinegar, citrus, tomatoes, salted foods or seafood. Avoid the dishwasher. There is no need to oil it as you would carbon steel, but washing, wiping and drying are still essential.
Ginsan in tri-ply knives
Ginsan is often used in tri-ply knives, with the hard Ginsan as the core and softer metal on both sides. The Ginsan core appears at the cutting edge. According to Takefu Special Steel, tri-ply steel combines a high-grade steel with a relatively inexpensive base metal, giving both sharpness and toughness at a good price. It describes tri-ply as the type most often used for kitchen knives.
The outer layers are not always soft iron. Some knives use soft stainless steel instead. With soft iron outside, the sides of the blade will rust; with stainless outside, the sides resist rust as well. When choosing a knife, look at what is used on the outside as well as the core steel.
The same source notes that single-bevel Japanese knives are mostly made from two-layer steel rather than three. "Ginsan always means tri-ply" is not the case.
Good uses, and uses to avoid
Ginsan is an easy steel for foods with plenty of moisture: all-round knives such as the santoku, gyuto and petty, or the yanagiba and usuba used for fish and vegetables. It seems well suited to people who like the cutting character of Shirogami or Aogami but want less rust management.
As with any hard edge, a few cautions apply. Do not cut frozen food. Do not strike bones or shells. Do not pry or twist the blade. Do not use it on a glass or stone cutting board. None of this is specific to Ginsan, and it also depends on the thickness and shape of the blade. Choose by the shape of the knife for the job you want it to do.
Names used abroad
In overseas knife shops, "Ginsan" is the name most widely understood. "Silver #3," "Silver 3," "Ginsanko," "G3" and "GIN3" are also used. A direct translation of the Japanese "Gingami 3-go" is rarely seen.