With its premium series Select II, the whetstone manufacturer Sigma Power Corporation from Tokyo addresses users of high-alloy steels such as HSS. These stones, too, are obviously intended to engender a grinding experience similar to that of natural stones. The special production process is expensive, but the Sigma Select II probably has no equal when it comes to demolishing steel.
Now you may wonder, if a finer stone produces a better cutting edge why do I need a coarse stone at all? The answer is that finer stones work much more slowly than coarse ones. The amount of metal a fine stone removes with each pass is much less than what a coarse stone removes. If you have an edge with a good shape to it from a coarse stone, this is not a problem because the fine stone doesn’t have to remove much metal to improve the edge. If the edge is dull, it will take many times longer to reshape it with a fine stone than it would with a coarse one.