How should I care for a 1090 carbon steel katana during long-term display?
Updated Mar 2026
Carbon steel - including 1090 - is susceptible to surface oxidation when exposed to humidity, airborne salts, or fingerprint oils. For long-term display, apply a light coat of choji oil or high-grade mineral oil to the blade surface every two to four months using a soft, lint-free cloth. Store or display the katana away from exterior walls where temperature fluctuations drive moisture cycling. If your display environment has humidity above 60%, consider a cabinet with silica gel desiccant packs. Always handle the blade with cotton gloves or by the tsuka to prevent oil transfer from skin. When storing inside the saya for extended periods, remove the blade periodically to ensure no moisture is trapped at the habaki collar.