BladeThe abrupt transition from the softer steel in the body of the blade to the hard martensitic cutting edge indicates a laminated construction with high carbon steel at the center of the blade's cross section and a hardening water quench from the hot-forging temperature. There would be no such abrupt transition edge if differential hardening were used in the manner of the Japanese swordsmith. The surface pattern was made visable by first polishing the edge, then rubbing in a water slurry of a Japanese hatsu-ya thumb stone and finally, very lightly etching with dilute hot solution of ferric sulfate to enhance visual contrast between steels of different constitution.
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