San Mai III is of questionable value, period. It's strictly marketing.
The whole idea behind laminated, or sandwiched, steel blades is that you have an inner steel that is high carbon for cutting power while the outer steel contains less carbon, adding toughness and corrosion resistance. The outer steel thus protects the inner steel.
The problem with the San Mai III is that the steels are too similar to add real diversity to the blade. Cold Steel makes many knives made of VG-1 stainless and they're tough and have more than adequate cutting power and corrosion resistance. With San Mai III, as I understand it, they take VG-1 and they layer it with 420.
It would be one thing if the inner steel were Carbon V or S30V, and the outer was 420, but dream on. Cold Steel finished these knives very well, but I wouldn't expect 420 to offer me appreciably tougher or more corrosion resistance qualities to make a difference. In fact, it's kind of a joke. For the price, you should get a better inner steel, but Cold Steel has never produced exceptional stainless since its inception.
If you think of it as a quarter, it may be a good comparison. You have a copper alloy in the middle and some sort of a nickel outer layer, but it's still a worthless coin. It may wear better than a 90 percent silver quarter, but it'll never be worth what a silver quarter is worth. So why pay a silver quarter price for a cheap, laminated quarter?
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