Traditional Japanese steels (high-carbon steels) are the first choice of Japanese chefs because they allow knives to be forged with high hardness (HRC) and are easy to sharpen at the same time. Knives made from such steels have an extremely fine edge, but they also require special care, as they need to be wiped well and oiled occasionally. Improper care and maintenance can cause the blade to develop rust.
Unlike a patina, rust does not protect the blade, but accelerates further corrosion wherever it has already developed. If rust is observed on the blade, it needs to be removed before using the knife again.
To clean it up, you can use a coarse kitchen sponge, a rust eraser, or fine wet sandpaper (with a grit size between 500 and 800). Care must be taken not to scratch the surface of the knife, so slow and careful fine sanding or smoothing is recommended. You also want to pay special attention to the Damascus pattern or Kuro-uchi finish, as they can fade if they are scratched too hard. Once you remove a Kuro-uchi finish, you cannot bring it back to life.
Did your knife get a little rusty? Order your Naniwa Rust Eraser and get scrubbin'!
Want to learn more about rust, patina and the differences between them? Check out our blog post What is Patina? Is it Good or Bad for Your Knife?
