SK-5 Carbon

Japanese equivalent of 1080; a tough, plain carbon steel.

Typical hardness

58-60 HRC

Edge retention

2/5

Toughness

4/5

Corrosion resistance

1/5

Ease of sharpening

5/5

1-5 is a relative ranking drawn from published composition and hardness, not a lab measurement. Higher is better on every axis, and no steel is a 5 across the board — edge retention and toughness pull against each other.