What is the best way to store and maintain a blue carbon steel katana?
Updated Mar 2026
Carbon steel, including the 1065 alloy used in these blades, is reactive to moisture and will develop rust if left unprotected. For display storage, the blade should be lightly coated with a thin application of choji oil, mineral oil, or a dedicated sword oil before being placed in its saya. Avoid storing the katana in humid environments such as basements or rooms with poor air circulation. A horizontal or angled wall mount keeps the blade properly supported and prevents pressure deformation of the saya over time. Inspect the blade surface every two to three months — if you notice any dull spots or faint discoloration on the blue finish, a fresh application of oil and a soft cloth wipe is usually sufficient to restore the appearance and protect the steel.