What is clay tempering, and which tachi pieces in this collection feature it?

Clay tempering is a heat-treatment technique in which a mixture of clay is applied along the spine and flat of the blade before the quench, leaving only the edge area exposed. During the rapid quench in water or oil, the uncoated edge cools faster and achieves greater hardness, while the clay-insulated spine cools more slowly, remaining tougher and more flexible. The result is a blade with a visible hamon - the wavy or straight line separating the harder edge from the softer body - which is one of the most prized visual features in Japanese sword collecting. The clay tempered 1095 carbon steel tachi with teal ito wrap in this collection explicitly undergoes this process, producing a blade with both authentic structural character and strong display appeal.

What steel types are used in display-quality tachi blades?

Display-quality tachi in this collection are offered in three main steel types, each with distinct visual and structural characteristics. Damascus steel features layered folded patterns across the blade surface that become especially visible under directional lighting - a visually striking choice for wall display. T10 high-carbon steel, when clay-tempered, produces a genuine hamon temper line along the edge, a detail that serious collectors associate with traditional craft accuracy. 1095 high-carbon steel provides a clean, well-polished finish with reliable structural consistency, often preferred for full sets where visual uniformity across multiple pieces matters. None of these are stainless steel, so all three benefit from periodic light oiling with choji or mineral oil to maintain the blade surface during long-term display.

How should a tachi be stored and maintained at home?

A tachi is ideally stored or displayed edge-downward on a dedicated stand - the historically correct orientation that also reduces stress on the habaki fit. Apply a thin coat of camellia or mineral oil to bare steel every two to three months using a soft cloth, wiping from the spine toward the edge rather than along it. Never apply oil to the ito wrap, tsuka wood, or saya interior. Keep the piece in an environment where relative humidity stays between 45 and 55 percent; a small silica gel packet in a closed display cabinet is an inexpensive solution. Avoid positioning the display near heating vents or windows, as temperature swings cause both wood and steel to expand and contract at different rates, which can loosen fittings over time.

How should I maintain a carbon steel tachi for long-term display?

Carbon steel blades - including 1095, T10, and Damascus variants - are susceptible to oxidation if left untreated. For long-term display, apply a thin coat of choji oil or a food-grade mineral oil to the blade surface every one to three months, depending on your local humidity. Use a soft cotton cloth or a traditional uchiko ball to distribute the oil evenly and avoid leaving fingerprints, which contain salts that accelerate surface corrosion. Store the sword horizontally or at a slight angle on a display stand, edge-up, in a low-humidity environment. Avoid storing the blade inside the saya for extended periods without periodic inspection, as moisture can become trapped and cause spotting on both the blade and the lacquered scabbard interior.

How should I store a tachi collectible to prevent corrosion?

Updated Mar 2026

Carbon steel blades — whether Damascus, 1095, or high-manganese — will oxidize if left unprotected, particularly in humid environments. For long-term display storage, lightly coat the blade with a thin, even layer of choji oil (clove oil blended with mineral oil) using a soft, lint-free cloth. Wipe off excess oil before returning the blade to the saya, as pooled oil inside a lacquered scabbard can damage the interior lining over time. Store the sword horizontally on a sword stand, edge facing upward in the traditional Japanese orientation, in a low-humidity environment away from direct sunlight. Inspect and re-oil every three to four months. Avoid handling the blade directly with bare hands, as skin oils accelerate surface oxidation.