I sharpen knives professionally, all by hand so I have a lot of experience with a wide range of Japanese Water Stones. I have purchasing my stones from Paul for quite some time, and the Naniwa Chosera line has been my long time favourite, so I was a little apprehensive when I heard about the new Naniwa Professional stones coming out, That was until I had the opportunity to actually use the new 400 Naniwa Professional stone. I have since sharpened over 100 knives using this stone and it is absolutely exceptional. If you are like I was and worried about this new line up, don't be, you are in for a treat. They work quickly and dish very slowly. I couldn't be happier and I can't wait to use the other Naniwa Pro stones. Thank you Paul, once again.