How should I maintain a carbon steel katana on long-term display?
Updated Mar 2026
Carbon steel blades - whether T10, 1045, or spring steel - require routine care to prevent surface oxidation, especially in humid climates. Every two to three months, apply a thin, even coat of choji oil (or a food-grade mineral oil substitute) using a soft cloth or dedicated uchiko ball. Before oiling, remove any existing residue to avoid buildup. Store the katana horizontally on a display stand rather than inside the saya for extended periods, as prolonged contact between blade and lacquered wood can trap moisture. Keep the display environment below 60% relative humidity, away from heating vents and direct sunlight, both of which can dry and crack the ito wrap and lacquer finish. With consistent care, a properly maintained carbon steel katana will retain its surface character for decades.
