Originally Posted by
Steve56
Shapton make 3 different stones that we're familiar with in the US, the Pro/kuromaku, the HR Glass Stone (white), and the HC Glass Stone (grey). The Pro is an older stone favored by many, the HR series was designed to cut the Lie-Nielsen plane steel and is a fast aggressive stone, and the HC (high carbon) was designed for high carbon steel. The HC is similar to the Pro in performance but I don't think it's the same stone.
In terms of polishing from least to most, HR -> Pro -> HC
The HR is fastest, the Pro and HC are similar in cutting speed.
Before I neutered autocorrect, it wanted to make 'Shapton' into 'Sharpton' so you almost had your own line of stones Tom.
Hope this helps!
Cheers, Steve