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yes, I consider 3-10 strokes fast, 10-20 medium, above that slow
the people who use it on a regular basis report 50-100.

it is a natural stone, so the actual grit rating is anything from 1000 to 8000 (look up the grit definition and you'll know why).
but somebody felt it polishes like a 12k synthetic stone (which one...

yes, it's really chinese, but it's not really 12k :)