Sanmai(Three-Piece) is a common construction for double bevel knives where two pieces of softer cladding steel are forgewelded to each side of a harder core steel. The harder but more brittle core steel will form the hard cutting edge after heat treating, and the softer cladding will support the core to increase the overall strength of the blade.

The soft cladding enables the thinning process to be a lot easier than a honyaki or monosteel construction. And in the case where the cladding steel are stainless in nature, it can offer protection for the carbon or semi-stainless cores against rusting and discoluoring.

"Migaki" means "polished" or "shined" in Japanese, The term "Migaki finish" in the context of Japanese kitchen knives indeed does not exclusively refer to a mirror polish but encompasses a broader range of polished finishes that can vary from semi-gloss to a more refined, subtle sheen, rather than a highly reflective surface. The primary goal of a Migaki finish is to enhance the knife's functionality and aesthetic appeal, focusing on a smooth finish that improves resistance to corrosion and minimizes drag during cutting, rather than achieving a purely mirror-like appearance.