Visually, a very sharp knife has an edge that is too small to see with the eye; it may even be hard or impossible to focus in a microscope. The shape near the edge can be highlighted by rotating the knife and watching changes in reflection. Nicks and rolled edges can also be seen, as the rolled edge provides a reflective surface, while a properly straightened edge will be invisible when viewed head-on.
However, due to limited natural deposits and extensive quarrying over the centuries, true, high quality, Japanese water stones are now few and far between and are very expensive. Thus, various companies are now producing synthetic Japanese Water Stones which generally have a more consistent composition and grit size than natural stones as well as often begin somewhat harder and thus, lasting a bit longer; not to mention being cheaper to purchase.
Start off on the rough grit side of the stone. Check the grit on your stone, or the packaging that came with the stone, to identify which is which. In general, whetstones and diamond stones each have different grits on either side. The rough grit side is used to grind the steel down, while the fine grit side is used to sharpen or hone the knife. The grinding process comes first, so you start on the rough grit side.
Cutting angle – With a manual stick or sharpening stone you set the angle yourself so this does not factor into the equation when choosing that type of sharpener. When shopping for an electric sharpener however it does. You’ll want to decide if you want your knives to have the 15 degree “Asian” style angle so that you can make precise cuts or the Western standard 20 degrees or 22-degree sharpening angle. Most people will opt for the 20 or 22-degree angle simply because their cuisine doesn’t call for a lot of finesse from their knives and those knives are probably of a heavier Western variety anyway.
So, as you can see, there are numerous different types and grades of whetstones on the market today and each has its advantages and disadvantages. Therefore, the right practice to choose the right sharpening stone for you is to choose a whetstone material based upon how fast you need to remove metal and how fine an edge you need. For instance, although they are often the most expensive type of whetstone, diamond hones generally cut the fastest even in their finer grits followed by Crystolon Stones and then India Stones which are then generally followed by Japanese Water Stones and then by Novaculite, Belgian Blue, and Coticule whetstones in terms of how fast they remove metal. However, it should also be noted that the rougher an edge is, the less sharp it is while, the more polished an edge is, the sharper it is and thus, rough edges are fine for some tools while other tools require a much finer edge and, hunting knives require the finest edge of all. Therefore, the trick to choosing the proper whetstone for any given sharpening purpose is to purchase multiple stones with varying grits to accomplish each given task from cutting an initial bevel or defining a damaged edge to refining an existing edge to polishing it. We hope this article helped you. Feel free to leave a comment below if you have questions.
You need to adjust your fingers as you move the knife back and forth. Because sharpening takes place under your fingers, start with them at the tip and, as you pull the knife back toward you, release pressure completely and pause. Then, shift your fingers just a little down the blade toward the heel. This finger dance is critical and takes time getting used to.
We tend to recommend natural Japanese water stones only to experienced users who are thoroughly familiar with the synthetic Japanese sharpening stones. Natural stones are not to everybody’s taste and there are inevitably many uncertainties with regard to their grit grade, which cannot be determined exactly, their hardness and their suitability for certain types of steel. 

I purchased this set together with the 400/1000 grit stone assuming that some of my knives were quite dull and would need work on a coarse grit stone. Premium Whetstone Sharpening Stone 2 Side Grit 400/1000 | Knife Sharpener Waterstone with NonSlip Rubber Base & Flattening Stone. This is my first wetstone. First off I tried to sharpen my Chicago Cutlery boning knife. This knife is nearly thirty years old, has been abused in may ways and was quite dull. It was very difficult for me to get a burr on this blade, which I attribute to poor technique. Next I moved on to my Henckels Professional S paring and chef's knives. The paring knife was moderately sharp and was modestly improved after working over all three grits of stone. It would cut paper but again it was difficult to develop a burr with this blade. Undaunted I switched to the chef's knife. This knife is twenty years old and has never been professionally re-sharpened. I have sharpened it twice with a Lanksey sharpening system which marred the finish but did put a good edge on the blade. Lansky Standard Coarse Sharpening System with Fine Hones. The chef's knife was moderately dull and had several pits visible on the cutting surface. I modified my technique for passing the knife over the stone and worked the chef's knife over the 400 grit stone aggressively and eventually I was able to get a burr to form from the tip of the knife all the way to the handle. From there it was a simple process of reforming the burr on the 1000 grit stone and then finishing on the 6000. After sharpening, the chef's knife easily and cleanly slices a tomato with very light pressure and is in my opinion very sharp. Not sushi knife sharp but more than enough for the chopping and slicing I expect of it. I'm looking forward to going back and working both the boning knife and the paring knife over again. Don't expect a good result from this product the first time you use it. Watch videos on using a wetstone, expect to spend at least twenty minutes per knife at first, and practice forming a burr. If you can form a burr, you will be able to successfully sharpen your knife.