Iron clad carbon steel, though no details on steel type. 220mm edge, approx 47mm wide, weighing 175-180 grams. Blades taper in thickness from 4mm at heel Forged approx 1950 - 1970.
'San-mai' means ‘three layer’ referring to three layers of steel with iron clotting. These blades have been recently cleaned and sharpened but otherwise unused. We have a small batch of these, and each is slightly different. Super unusual to find!