How should I care for a clay-tempered katana in long-term storage?
Updated Mar 2026
Clay-tempered blades with real hamon require attentive maintenance to preserve both their visual character and surface integrity over time. The most important routine is light oiling: apply a thin, even coat of choji oil or mineral oil to the blade surface every two to three months, or more frequently in humid climates. Use a soft, lint-free cloth to spread the oil and remove any fingerprint residue — oils from skin contact accelerate oxidation on high-carbon steel. Store the katana horizontally on a display stand or in its saya (scabbard) with the edge facing upward in the traditional orientation. Avoid storing inside a sealed bag or airtight case, as trapped moisture promotes rust faster than ambient air. If the blade develops minor surface rust spots, a light application of oil and gentle buffing with a uchiko powder ball or fine polishing cloth can address early-stage oxidation without professional intervention.