The basic concept of sharpening is simple – you're using an abrasive edge to remove metal – but the knife you buy may alter the method you should use. A general rule of thumb is that a waterstone can be used for both Japanese- and Western-style blades, but you should avoid pull-through sharpeners for Japanese knives (or any knife with very brittle blades).
The smaller the angle between the blade and stone, the sharper the knife will be, but the less side force is needed to bend the edge over or chip it off. The angle between the blade and the stone is the edge angle – the angle from the vertical to one of the knife edges, and equals the angle at which the blade is held. The total angle from one side to the other is called the included angle – on a symmetric double-ground edge (a wedge shape), the angle from one edge to the other is thus twice the edge angle. Typical edge angles are about 20° (making the included angle 40° on a double-ground edge).[1] The edge angle for very sharp knives can be as little as 10 degrees (for a 20° included angle). Knives that require a tough edge (such as those that chop) may sharpen at 25° or more.
Before you start sharpening, soak the stone in water for around five to 10 minutes, until it absorbs the water and a liquid film appears on the surface. After soaking, splash some water on top, and re-splash during the process if it ever gets too dry. You'll get a dark, splotch of steel and stone building up on the stone while you're sharpening the blade. This is totally normal so just splash the stone with some water to clean it off and allow it to perform more efficiently. 

Keep your knife razor-sharp with a high-quality sharpening stone. We offer a wide variety of sharpening stones, such as Arkansas stone, Diamond stone, Bench stone, Water stone and more. Whether you own a pocket knife, a hunting knife or a kitchen knife, a sharpening stone is essential for preventing your blade from becoming dull.  Most of our sharpening stones are lightweight and portable, so you can use them at home or take them with you wherever you go.

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.
In addition, the most prized of the natural Japanese Water Stones are quarried in the Narutaki District north of Kyoto, Japan and are commonly available as either bench stones or pocket stones in grits ranging from 120 to 12,000. On the other hand, synthetic water stones are made from Aluminum Oxide and commonly available as either bench stones or pocket stones as well in grits ranging from 220 to 8,000 and, although this is the same abrasive material used to make India Oil Stones, the difference between the two is that the binder that holds the abrasive together enables Water Stones to be much softer than India Oil Stones which, in turn, promotes faster cutting because the worn abrasive material breaks away more quickly and is replaced with fresh, sharp, abrasive material more quickly. In addition, because water stones do not become glazed or loaded with swarf like oil stones can, new abrasive particles are constantly exposed as the stone wears so it continues to cut consistently. Plus, they can be lubricated effectively with water (rather than oil which can ruin some water stones) which combines with the fine particles of abrasive from the surface of the stone to form a slurry which polishes the bevel as the stone cuts. However, it should also be noted that Water Stones do become uneven significantly faster than other types of whetstones although, their softness does make them easier to true again.