When you make a sword, you shape the metal, folding it over itself to create strength. But the metal's still soft. [... he can hear another's voice answering his own question about the term so long ago, and his own voice is far off.] It needs to be heat tempered to achieve the necessary hardness.
But the hardness can't be the same all over. The body of the blade needs to be tough but flexible... but something like that's too soft for the edge. And if the entire blade becomes that hard and not just the edge? It breaks because the metal is brittle.
So to create that difference, the cutting edge is covered in a thin layer of clay, and the rest of the blade is covered in a thicker layer to insulate the body better. It's allowed to dry, then at night, it's heated to the right temperature, slowly.
Then it's plunged into water and that's when the moment of truth arrives.
[action]
[... sip...]
When you make a sword, you shape the metal, folding it over itself to create strength. But the metal's still soft. [... he can hear another's voice answering his own question about the term so long ago, and his own voice is far off.] It needs to be heat tempered to achieve the necessary hardness.
But the hardness can't be the same all over. The body of the blade needs to be tough but flexible... but something like that's too soft for the edge. And if the entire blade becomes that hard and not just the edge? It breaks because the metal is brittle.
So to create that difference, the cutting edge is covered in a thin layer of clay, and the rest of the blade is covered in a thicker layer to insulate the body better. It's allowed to dry, then at night, it's heated to the right temperature, slowly.
Then it's plunged into water and that's when the moment of truth arrives.