These grit ratings can make you go nuts. I use choseras and I've done 1,3,5,10 then finisher, I've also done 1,5,10, but raise a little slurry on the 5 for the same result in visual scratch reduction. In a synthetic progression I finish on the 20k suehiro, but I also use the 15k suehiro and find the blade is smoother with the 15 then without it. I find the Norton 8 leaves finer scratches than the chosera 10. The shapton 30 k is .49 microns, the suehiro 20 k is .5 microns. I'm sure its done to confuse us and buy more stones.