Wikipedia to the rescue:

Sandpaper Chart

This seems to indicate that my 2000 grit sandpaper has average grain size of 10 microns. So it does appear to be about the same as your 2000 Japanese. I wonder about the honing compound I put on the Tormek's leather wheel?

Also from Wikipedia:
Scary Sharp

I first heard about this method on the old usenet back in the day, as described in the wiki article. I found the wiki article as a link from the waterstones page :-) CB.