Originally Posted by DrThunder88
53 HRC (a dimensionless number, not a degree or percentage) is pretty soft for most knives not being used to hack through heavy underbrush, and the website doesn't even specify which Rockwell scale is used. That makes it seem a little odd as Japanese knives are usually prized for their hardness. I can find nothing on the steel used in the Sai knives (or anything else about them for that matter!), so it's not likely to be a high-performance steel, but anything kept that soft will likely be very corrosion resistant.
HRc 53. Wow. Those will sharpen in seconds but unfortuately the edge will fold like a napkin. They will have to be realigned with nearly every use.
Dr. T - The Rockwell "C" scale is the only Rockwell scale used for knife hardness.
Here's the list:
A Cemented carbides, thin steel and shallow case hardened steel
B Copper alloys, soft steels, aluminum alloys, malleable iron, etc.
C Steel, hard cast irons, pearlitic malleable iron, titanium, deep case hardened steel and other materials harder than B 100
D Thin steel and medium case hardened steel and pearlitic malleable iron
E Cast iron, aluminum and magnesium alloys, bearing metals
F Annealed copper alloys, thin soft sheet metals
G Phosphor bronze, beryllium copper, malleable irons
H Aluminum, zinc, lead
K, L, M, P, R, S, VBearing metals and other very soft or thin materials, including plastics.