From my reading and discussion with others, it seems that jnats are usually used either as a final finisher or, with a progression of nagura stones, as a one stone system after the bevel is set. Have not heard the following described:
Over the past couple of years, I acquired a couple of jnats from trusted members here, neither of which had proved useful to them using traditional strategies. One is grayish, with a lot of brown splotches, lines, etc. The member estimated it to be equivalent to a 4K synthetic. The other wasn an asagi in appearance, no info re mine, strata, etc., but estimated by that member to operate at about the 8K level.
Hmmm.... a 4K and an 8K. Since I have several Nakayama finishers, it dawned on me I might have a convoy goin' here
Set a bevel on a Giessen and Forster (sp?), then did about 20 circles and 20 x strokes on the"4K" then the same on the "8K." Followed with a light slurry on my Nakayama kiita, dilut every 15 strokes to water. Took less than half the time of my usual progression on Naniwa SSs.
Didn't expect a hit on the first time, but the HHT and TPT were encouraging. End result: sharp, a little harsh, great shave. About 20 laps on the kiita settled the harshness issue.
I feel very fortunate to have these natural stones I can use in a synthetic style progression. Anyone else doing it this way?