Rust on Kuroichi?

[Miyamoto Musashi]

Hi all,

I’ve noticed some brown spots on the Kuroichi finish of my Hisamoto. I don’t believe they were there before. When wiping the spot, there is no brown residue that comes off (which is characteristic of light rust).

Can anyone identify whether this is rust? If not, then what is it? Is it even possible for rust to develop on a Kuroichi?
Thank you all!

 

[HumbleHomeCook]

Kuroichi may not be right for you.

 

[Miyamoto Musashi]

Kuroichi may not be right for you.

So this is or isn’t rust?

 

[Moooza]

Kurouchi finished knives can definitely rust. It resists rust a little, but that's it. In your case though, I think that is just dirt or other residue from forging. You can see the same in this pic: Morihei Hisamoto Kurouchi | 210mm Gyuto Knife (Shirogami) - With Bolster

 

[Infrared]

It is not rust.

It was either already like that or some of the kurouchi flaked off.

 

[coxhaus]

Automatic transmission fluid is a great rust remover. Leave it on for a while and then wash it off with soap.

 

[KnightKnightForever]

Automatic transmission fluid is a great rust remover. Leave it on for a while and then wash it off with soap.

Thanks man

 

[mengwong]

It might be no more than an old wives’ tale but in situations like this I like boiling water to try to turn Fe2O3 into Fe3O4.

I’ve been doing this ever since I watched

Provocative sciencing from an earlier era:
Passivation of Carbon Knives

 

[gentiscid]

Bar Keepers Friend

 

[simona]

Had the same spots on Shigefusa, Mizaki and Okuba Kijaya KU finishes.
It goes with use and washing I have found.

 

[blokey]

Most of those are actually left front the die tool they used, not from the knife itself.