Aogami #2 (Blue Paper Steel No. 2) is the most popular and widely used grade in the Blue Paper series by Hitachi Metals. It is considered the "standard" or "balanced" version of Blue Steel, offering a near-perfect equilibrium between extreme sharpness, edge retention, and ease of sharpening.
Key Characteristics
The "All-Rounder" Carbon Steel: While #1 is harder and "Super" is more wear-resistant, Aogami #2 is the favorite of many blacksmiths and chefs because it is slightly tougher and more forgiving to work with.
Wicked Sharpness: Like all Blue Paper steels, it has a very fine grain structure. It can be sharpened to a "surgical" level of sharpness that feels more aggressive and "toothy" than stainless steel.
Excellent Edge Retention: Thanks to the addition of Tungsten, it holds its edge much longer than standard carbon steels (like 1095 or White Steel #2). It typically operates at a hardness of 61–63 HRC.
Better Toughness than #1: Because it has slightly less carbon than Aogami #1, it is less brittle and less prone to micro-chipping during daily kitchen tasks.
Highly Reactive (Non-Stainless): It will rust and discolor quickly. It requires immediate wiping and drying after use. Over time, it will develop a beautiful blue-grey patina that helps protect the steel from deeper corrosion.
Chemical Composition
Carbon (C): 1.05% – 1.15% (Provides the high hardness)
Tungsten (W): 1.00% – 1.50% (The key alloy that increases wear resistance)
Chromium (Cr): 0.20% – 0.50% (Increases stability and hardenability)
Manganese (Mn): 0.20% – 0.30%
Common Applications
Japanese Kitchen Knives: It is the most common steel for high-quality Santokus, Gyutos, and Nakiris. It is often used as the "core" steel in a stainless-clad blade (San Mai).
Higonokami Pocket Knives: The classic Japanese folding knife almost always uses Aogami #2 for its blade.
Outdoor & Hunting Knives: Many Japanese outdoor makers use Aogami #2 because it is easy to maintain in the field but stays sharp through heavy use.
Aogami #2 vs. Shirogami #2 (White Steel)
Aogami #2: Stays sharp longer and is easier to heat-treat consistently.
Shirogami #2: Can achieve a purer, finer edge and is even easier to sharpen, but loses its "razor" edge much faster.