How to Care for Your Higonokami: Rust Prevention, Brass Patina, and Maintenance

Most authentic Nagao Higonokami knives are forged from Aogami (Blue) or Shirogami (White) steel. While these steels offer legendary sharpness, they are not stainless. Without proper care, they will rust. Understanding this is the first step to owning a Japanese classic.

To keep your blade pristine, follow these three steps:

• Keep it Dry: Never leave your knife wet. After cutting fruit or working in damp conditions, wipe the blade immediately with a microfiber cloth.
• The Protective Layer: Apply a thin coat of Camellia Oil (Tsubaki Oil) or food-safe mineral oil. This creates a barrier between the steel and the oxygen in the air.
• Avoid Leather Sheaths for Long Storage: Leather can trap moisture and tannins that accelerate corrosion. For long-term storage, a wooden box or a dry cloth wrap is better.

The brass handle of a Higonokami is a "living" material. Over time, it will lose its bright shine and develop a deep, dark patina.

• Embrace the Aging: Most collectors prefer the aged look as it tells the story of the knife's use.
• Restore the Shine: If you prefer the "gold" look, use a metal polish like Pikal or a simple paste of lemon juice and baking soda to gently buff the handle back to a mirror finish.

Since the Higonokami is a friction folder (no mechanical lock), the tension is held by the pivot rivet. If the blade becomes too loose:

1. Place the knife pivot on a solid, flat metal surface (like an anvil or a heavy hammer head).
2. Use a small ball-peen hammer to gently tap the rivet.
3. Test the friction after every two taps. Caution: Do not over-tighten, or the blade will be difficult to open.

Dirt and pocket lint often accumulate around the Chikiri (the thumb lever). Use a wooden toothpick and a drop of oil to clear out the debris to ensure a smooth opening action every time.