Honyaki
Honyaki — 本焼 — (literally "true-fired") is the name for the Japanese traditional method of metalwork construction most often seen in kitchen knives, but also other tools. By forging a blade with a technique most similar to the tradition of nihonto, from a single piece of hard high-carbon steel, which is covered with clay during part of the processing, to yield upon quenching, three distinct parts to the blade: a flexible and resilient spine a hamon — a temper line running the length of the blade a hard, sharp cutting edge Further, this steel can be either mizu honyaki, water-quenched, or abura honyaki, oil-quenched.