If you don't have any, I highly recommend the Naniwa's. They are inexpensive, and give excellent results. I'll probably buy the entire set. I hear good things about the Nakayama's. The Japanese naturals are nice hones, probably inconsistent because they're natural. I haven't pulled the trigger on any yet, I've been in touch with OS a few times, but haven't done it yet. I'm looking forward to the 16k, I hope it improves my edge. Good luck with your 30k. Post your results and let us know....