I stopped at the 10k superstone because I have the Suehiro Gokumyo 20k to finish with Synthetic wise. Way I see it I could probably have stopped at the 8k, as the jump to the 20k works, but, now I've gotten a few Japanese natural stones, and they are solely hard stones for finishing and so far I've gone from the 10k to the jnats and touch wood, things are going very well. Only problem is that I suffer like many from HAD and it's only a matter of time before two jnats become three.......you know the rest guys....