After every session
- Rinse and wipe with a soft cloth and a little mild soap if needed.
- Dry it completely — blade, bolster and the joint where the handle meets the tang.
- Put it away dry. Never leave it in a sink or a drying rack.
Carbon steel will darken and take a patina with use. That is normal. Orange rust is not: remove it with a fine abrasive and dry the blade more carefully.
Boards and surfaces
End-grain wood is kindest; soft plastic is acceptable. Glass, ceramic and stone countertops will roll a fine edge in a single session.
Storing
A magnetic strip, a saya, or a blade guard in a drawer. Never loose among other tools.
Sharpening
A whetstone in the 1000 to 3000 grit range covers almost everything. A few light passes at roughly fifteen degrees per side brings a fine edge back long before it feels dull. Single-bevel knives are sharpened flat against the bevel with the ura laid almost flat on the stone.
Steel notes
Aogami Super and Shirogami #2 are carbon steels. They take a keen edge and hold it, and they will mark and patina. Ginsan is stainless and more forgiving of a busy service, though it still deserves a dry blade and a proper board.