Heat Treatment Specifications
Austenitizing
Temperature815°C(1499°F)
Soak Time12 minutes
Tempering
Temperature180°C(356°F)
Time120 minutes
Cycles2x
Quench Medium
oil
Target Hardness
64 - 65 HRC
Performance Characteristics
Toughness5/10
Edge Retention5.5/10
Corrosion Resistance1.5/10
Ease of Sharpening7/10
Overall Score19/40
Interesting Facts
- 1Hitachi Metals 'Blue Paper #1' - highest carbon Aogami
- 21.25-1.35% carbon, 1.5% tungsten for wear resistance
- 3Named for blue paper wrapping at factory
- 4Harder than Shirogami due to tungsten/chromium additions
- 5Reaches 65-67 HRC with proper heat treatment
- 6More wear resistant but harder to sharpen than Shirogami
Famous Uses
High-end yanagiba
Professional sashimi knives
Premium chisels
Best For
High-end Japanese kitchen knives
Professional culinary use
Precision cutting tools
Similar Steels
Not Recommended For
- Wet environments
- Sharpening novices
- Dishwashers
Expert Tips
- 1Takes patina but resists rust with care
- 2Only steeling and stropping for weeks
- 3Better wear than Blue 2, less tough