How do I properly maintain a clay-tempered T10 katana in storage?
Updated Feb 2026
Clay-tempered high-carbon steel requires consistent, simple care to maintain its appearance over years of display. The most important step is applying a thin coat of blade oil — traditionally choji oil, though food-grade mineral oil works well — every two to four weeks, or more frequently in humid environments. When storing, keep the katana in its saya to shield the surface from airborne moisture and dust. Avoid airtight enclosures without a desiccant pack, as trapped humidity accelerates surface oxidation. Never store the blade in contact with synthetic materials that off-gas acids, such as certain foam types. For wall-mounted display, position the piece away from direct sunlight and heating vents. With this routine, a properly forged T10 blade will retain its original finish and hamon clarity for decades.