DMT® is recognized as the worldwide leader in diamond knife sharpeners and sharpening products, with a diverse product line and reputation for quality and innovation. DMT’s patented and award-winning products are known for their superior quality and versatility, are easy to use, and allow for sharpening in a fraction of the time required by other methods. DMT manufactures a full line of diamond knife sharpeners and other sharpening tools for use in woodworking, culinary arts, gardening, camping, fishing, hunting, outdoor and winter sports, industrial applications and more.
The Juuma sharpening and honing stones offer a simplified working principle while at the same time ensuring the highest possible quality in the offered grits. Juuma Cobalt Blue stones are made of an aluminium oxide and a bonding agent. Adding cobalt serves to slow stone abrasion and increase the speed of sharpening. The speed bonus is especially marked when stoning blue steel (blue paper steel that is often used for Japanese planes and chisels). The cobalt gives the stones their blue colour. Juuma is our proprietary brand. Juuma sharpening stones are produced by a renowned Japanese whetstone manufacturer.
This was the first Whetstone that I've ever purchased. After reviewing several 'how-to' videos, I jumped right in to use it. I found the process nearly meditative and the BearMoo stone extremely effective! The first knife I sharpened was very dull with small, jagged edges. The 1000 grit side effectively removed the jagged indentations and created a nice cutting edge. The 4000 grit side made the knife razor sharp. The process took nearly 40-minutes.
Hold your knife at approximately 20° in relation to the honing rod. Your angle doesn't need to be exact, just approximate. Whatever angle you decide to choose, or unwittingly end up choosing, make sure to maintain the same angle throughout the honing process. Changing the angle used during the honing process won't smooth out the metal in the blade as much as using a consistent angle will.[4]

The more you use the sharpening stone; the edges of each particle within the stone tend to become slightly rounded over time. When you notice that it is taking much longer to hone blades and edges, it means you need to replace the stone with a new one. Sharpening stones come with decks that make it convenient to keep the tool in balance on the stone.
We offer a series of oilstone packages that combine India and Arkansas stones and are very reasonably priced. At 8" long by 2" wide these stones are not as wide as some other types, but still wide enough for many edges and are plenty wide for knife sharpeners. Available in four price levels, these kits are a great opportunity for the beginning sharpener on a budget.
Believe it or not the company have put a bit of effort into refining the look of their product to make it more aesthetically appealing. Whether or not they’ve succeeded we’ll let you decide. Once you get accustomed to the Classic II however the results are undeniable and the whole thing will make perfect sense. Use it on your kitchen knives, hunting knives, utility knives and more and enjoy the same high quality finish every time.
Chefs will do this every day, and there's no reason you shouldn't too. Before cooking, or after you've done the washing up, honing your knife will help keep it in good condition. "When you're using a honing steel, you're not actually removing any metal at all, just re-straightening that edge, to get it back in line," says Authbert. Remember that you'll still need to sharpen it every two or three months. 
Be careful: Don’t move your fingers laterally along the edge, you’ll cut yourself. Feel for a rough area running from tip to heel. Again, it takes time to know what to expect because the best burr will be subtle. Just know that the bigger the burr, the more metal you are removing—more than necessary. Don’t worry, you won’t ruin the knife doing this. You’re learning here, and mistakes are part of the sharpening journey. Learn from them.
Historically, there are three broad grades of Japanese sharpening stones: the ara-to, or "rough stone", the naka-to or "middle/medium stone" and the shiage-to or "finishing stone". There is a fourth type of stone, the nagura, which is not used directly. Rather, it is used to form a cutting slurry on the shiage-to, which is often too hard to create the necessary slurry. Converting these names to absolute grit size is difficult as the classes are broad and natural stones have no inherent "grit number". As an indication, ara-to is probably (using a non-Japanese system of grading grit size) 500–1000 grit. The naka-to is probably 3000–5000 grit and the shiage-to is likely 7000–10000 grit. Current synthetic grit values range from extremely coarse, such as 120 grit, through extremely fine, such as 30,000 grit (less than half a micrometer abrasive particle size).[citation needed]
In addition, there are three broad grades of Japanese Water Stones consisting of the Ara-to (rough stone), the Naka-to (middle/medium stone) and, the Shiage-to (finishing stone). However, it should be noted that the various grades of natural Japanese Water Stones vary widely in both density and grit size from stone to stone and thus, they do not translate well to American or European abrasive standards. Furthermore, because they are significantly softer than Novaculite, Japanese Water Stones must be flattened more often and do not last as long as a either Novaculite or Coticule stones. But, because they form a slurry of fine particles when used, they also do a superior job of both cutting and polishing.
Some of the videos I watched suggested soaking the stone for 12-15 minutes prior to use. One suggested using vegetable oil on the surface versus water/soaking (I used water and presoaking it for 15-minutes). So instead of a simple 'out-of-the-box-and-use' approach, it required a bit of research before sharpening a knife. Otherwise I would have given this product a 5-star rating.