SK4 Carbon Steel vs Aogami Super

Detailed metallurgical comparison between JIS SK4 Tool Steel and Super Blue Steel.

SK4

SK4 Carbon Steel

JIS SK4 Tool Steel

A standardized Japanese Industrial Standard (JIS) carbon tool steel. Slightly higher carbon than SK5 and lower than SK2, making it one of the most balanced general-purpose tool steels in the JIS classification. Widely used for saw blades, knives, and hand tools where consistent heat treatment and predictable performance matter more than ultimate edge retention.

carbon0.90–1.00%manganese0.10–0.50%silicon0.10–0.35%
Sharpness
7
Edge Retention
6
Ease of Sharpening
9
Rust Resistance
3
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AOGAMI-SUPER

Aogami Super

Super Blue Steel

The highest-carbon variant among Aogami steels. Includes vanadium and molybdenum for extreme edge retention and hardness. Revered and feared in equal measure — its edge outlasts almost everything, but requires a master's touch to sharpen properly. The pinnacle of the Hitachi carbon steel family.

carbon1.40–1.50%chromium0.30–0.50%tungsten2.00–2.50%vanadium0.30–0.50%molybdenum0.30–0.52%
Sharpness
9
Edge Retention
10
Ease of Sharpening
5
Rust Resistance
4
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