Mark, I'm new to jnats, but I have no Nagura stones. The three jnats I have are all finishers so are hard. I notice you put a different slurry on your kiita. Could I for arguments sake put a slurry made from a Atoma 1200 and a Gok 20k? I'm a bit at sea with these things, but is there a rule to stop me putting a synthetic 12k slurry on one of my jnats. I don't get it mate?