Tomonagura made a review of the gokumyo 20k, and he came to the conclusion that it was a very nice feeling edge, but not nearly as comfortable or keen as a jnat finish and nearly unusable to use slurry on, only ended in microshipping.
I will have to humbly disagree. It is a very nice soft feeling edge.
I like a Jnat edge better too but that doesn't diminish the quality from the Gok.
Why would you even consider to slurry a synthetic ceramic base 20k stone anyway? I'm not sure anyone ever recommended such a thing.
Water only.
Bester/Imanashi stones are nowhere near the ballpark of the Gok.