Yeah, that slurry looks familiar! I have quite a few stones that have that same slurry.

The suita is a fast cutter, it not a finisher although I can still shave off it. I've used it for a few knives and it gives my knives a razor edge It produces a brown\black slurry quite quickly.

This Okunomon Suita has almost the same characteristics.
Name: 2013-10-01 18.59.56.jpg Views: 195 Size: 33.0 KB

Im guessing these would produce the same slurry\preform much the same as your Okudo Suita except your stone is probably a little harder?