How does clay tempering affect a tachi's hamon?

 Updated Mar 2026

Clay tempering is the process of applying a thick layer of refractory clay to the spine of the blade before the quench, leaving the edge exposed or coated with a thinner layer. When the blade is heated and plunged into water, the exposed edge cools rapidly and hardens into martensite, while the clay-insulated spine cools more slowly and remains tough. The boundary between these two zones becomes the hamon - a visible line of activity running along the blade. On T10 and Damascus steel, this line often shows nie (bright, star-like crystalline particles) and nioi (a misty, glowing band), both highly valued characteristics in authentic hand-forged collectibles. No two hamon are identical, making each piece genuinely unique.

Popular Products

20% OFFmodern wakizashi
209.00 USD
259.00 USD
15% OFFblack katana
179.00 USD
209.00 USD
20% OFFdamascus katana
619.00 USD
769.00 USD
15% OFFreal katana
649.00 USD
769.00 USD
15% OFFshirasaya katana
209.00 USD
249.00 USD
20% OFFdamascus katana
309.00 USD
389.00 USD
15% OFFkatana sword
199.00 USD
229.00 USD
20% OFFblack katana
159.00 USD
199.00 USD
20% OFFdamascus katana
329.00 USD
409.00 USD
20% OFFjapanese katana
229.00 USD
289.00 USD
15% OFFblack katana
179.00 USD
209.00 USD
15% OFFgolden katana
199.00 USD
229.00 USD
20% OFFmodern wakizashi
209.00 USD
259.00 USD
15% OFFblack katana
179.00 USD
209.00 USD
20% OFFdamascus katana
619.00 USD
769.00 USD
15% OFFreal katana
649.00 USD
769.00 USD
15% OFFshirasaya katana
209.00 USD
249.00 USD
20% OFFdamascus katana
309.00 USD
389.00 USD
15% OFFkatana sword
199.00 USD
229.00 USD
20% OFFblack katana
159.00 USD
199.00 USD
20% OFFdamascus katana
329.00 USD
409.00 USD
20% OFFjapanese katana
229.00 USD
289.00 USD
15% OFFblack katana
179.00 USD
209.00 USD
15% OFFgolden katana
199.00 USD
229.00 USD

Explore Our Collections