Hobby microscope view of a 220 grit diamond sharpening stone. Tiny diamonds are electroplated to a perforated metal carrier strip and bonded to a plastic backing. The feature identified with the red line across it measures about 0.08 mm across. The dark area at upper right is a void designed to allow for swarf created during sharpening to be cleared from the diamonds. This relatively coarse stone would be used to reshape a damaged blade edge which would be refined by finer grit stones.

I purchased this set as a gift to myself and my wife we both love to cook . It’s only been a couple of months we use them almost every day and the knives are excellent they are razor-sharp but I highly recommend you order the Whetstone for keeping them that way. I’ve used many different knives sets over my life and these seem to be by for the best quality.
I bought this and Unimi's 600/1000 whetstone at the same time. Curiously, reviews are currently blocked for their 600/1000 model, as amazon wouldn't let me leave one for it. Considering the conspicuous absence of reviews in the other stone's listing, one can only assume they're being censored for everyone. So, maybe I should be more critical of these stones, and use them a while longer before giving them any praise? But I've had a very positive experience with them so far, and the 600/1000 stone was the one I found most useful.
After several uses the Kamikoto is proving itself to be better than expected. As a professional I use different knives all the time and in fact have several thousand dollars worth of very fine blades of various manufacture. As it stands right now, if I could pick only one knife from all of them, I would take the Kamikoto. Fish, vegetables, raw meat, cooked meat, it handles them all very well and is a pleasure to use because of excellent balance and weight. And the edge… magnificent. Care and careful sharpening will be important, but then it always is with the finest of things. I would unhesitatingly recommend this product to people who appreciate the best. This is not a knife for fools or clumsy people. Buy, use, enjoy. And to the people at Kamikoto; “Thank You for making such a beautiful thing!”