How should I store a T10 carbon steel katana long-term?
Updated Mar 2026
T10 carbon steel is not stainless and will oxidize if left unprotected. For long-term display or storage, apply a thin, even coat of choji oil or pharmaceutical-grade mineral oil to the bare blade every two to three months - or monthly in coastal or high-humidity environments. Always handle the blade with cotton gloves, as fingerprint acids accelerate surface oxidation. Store the assembled katana horizontally with the edge facing upward inside the saya, and keep the assembly in a paulownia wood box or a padded sword bag to protect the lacquered scabbard from chips and dust. Avoid storing near heating vents or in areas with significant temperature swings, as repeated expansion and contraction can stress the lacquer finish on the saya over time.