San Mai III Stainless Steel for Knife Blades

San Mai III Stainless Steel

Manufacturer: Cold Steel(?)

San Mai III steel is a laminated stainless steel which consists of three layers of steel. The outer two layers are made of a softer, tough steel, sandwiching a harder, high carbon core that forms the actual cutting edge of the knife.

Earlier variants of San Mai III steel had an AUS-8 steel core, sandwiched by softer, tougher stainless sides possibly made from 420J2. Current San Mai III steel, sometimes called VG-1 San Mai III, uses a VG-1 stainless core which is a slight upgrade from AUS-8. San Mai looks very nice, but given the actual application of the knives in using this steel, the necessity of the San Mai construction is questionable. Cold Steel has a reputation for being all hype and gimmicks, and San Mai III steel is considered by many to be just another gimmick.

San Mai III is used exclusively by Cold Steel, and is manufactured exclusively for them in Japan. Since VG-1 is a proprietary product of Takefu Special Steel, it is possible that they manufacture the steel for Cold Steel.


Based on the assumption of 420J2 sides, and VG-1 Core.
  C Co Cr Mn Mo Si S Ni V
VG-1 0.95-1.05 - 13-15 - 0.2-0.4 - - <0.25 -
420J2 0.32 - 14-16 1 - 1 - - -
Values are shown in percentages.