What does "clay tempered" mean on a handmade katana?

 Updated Mar 2026

Clay tempering is a traditional Japanese heat-treatment process in which a layer of clay is applied to the blade before it is heated and quenched in water. Thicker clay is applied along the spine and thinner - or no - clay along the cutting edge. During quenching, the edge cools rapidly and becomes harder, while the spine cools more slowly and retains flexibility. The boundary between these two zones produces the hamon, the visible temper line that runs along the blade. This is a structural feature, not a cosmetic one, and it directly affects how the steel behaves along different parts of the blade. A genuine clay-tempered blade will show hamon activity under light - areas of nie (fine crystalline particles) or nioi (a misty glow) that form naturally during the process. This is one of the key markers collectors use to distinguish hand-forged collectibles from decorative replicas.

Popular Products

15% OFFmichonne's sword
199.00 USD
229.00 USD
15% OFFkatana sword
129.00 USD
149.00 USD
15% OFFobsidian katana
169.00 USD
199.00 USD
15% OFFkatana sword
179.00 USD
209.00 USD
20% OFFblack katana
159.00 USD
199.00 USD
15% OFFzoro katana
139.00 USD
169.00 USD
20% OFFzoro swords
349.00 USD
439.00 USD
15% OFFzoro sword
139.00 USD
169.00 USD
20% OFFkatana sword
159.00 USD
199.00 USD
15% OFFzoro sword
139.00 USD
169.00 USD
15% OFFichigo bankai sword
139.00 USD
159.00 USD
20% OFFenma sword
179.00 USD
219.00 USD
15% OFFmichonne's sword
199.00 USD
229.00 USD
15% OFFkatana sword
129.00 USD
149.00 USD
15% OFFobsidian katana
169.00 USD
199.00 USD
15% OFFkatana sword
179.00 USD
209.00 USD
20% OFFblack katana
159.00 USD
199.00 USD
15% OFFzoro katana
139.00 USD
169.00 USD
20% OFFzoro swords
349.00 USD
439.00 USD
15% OFFzoro sword
139.00 USD
169.00 USD
20% OFFkatana sword
159.00 USD
199.00 USD
15% OFFzoro sword
139.00 USD
169.00 USD
15% OFFichigo bankai sword
139.00 USD
159.00 USD
20% OFFenma sword
179.00 USD
219.00 USD

Explore Our Collections