How do I keep aogami carbon steel from rusting?

Dry it as soon as you finish, keep it somewhere dry, and let a patina build. Do that and aogami (Blue) steel will hardly ever rust.

Aogami #1, #2 and Super all have less than half a percent of chromium, nowhere near what a stainless steel needs, so water left sitting on the blade will spot it.

The routine:

• Wipe the blade as you go, especially after onion, citrus or tomato.
• When you finish, wash it in warm water with a little soap and dry it straight away with a towel. Don't let it air dry or leave it in the sink or the dish rack, and never put it in the dishwasher.
• Store it dry: on a magnetic strip, in a saya or in a block in a dry spot. A damp drawer is the worst place for it.
• If it's going to sit unused for a while, wipe on a thin film of camellia or mineral oil.
• Let a patina form. The grey, blue and brown colours you get from cutting meat and vegetables are a stable oxide layer, and it slows rust down. Orange or red specks are rust.

If you do find rust, lift light orange spots with a rust eraser and a little water, then dry and oil the blade. We stock the CKK and Naniwa rust erasers. Rust on the edge itself comes off the next time you sharpen. Deep pitting is a job for us, so bring the knife in.

On a stainless-clad knife only the thin line of aogami along the edge can rust; the cladding stays clean. A carbon-clad or honyaki blade can rust over its whole face and needs the same care all over.