The type and size of the blade being sharpened determines the size of the stone needed. In general , a 6" stone is considered a small sharpening stone, an 8" stone is a common larger size, and a stone larger than 8" (10"-12" are available) is considered generously sized. Stones smaller than 6" (3" and 4" stones are quite common), are considered pocket stones and can be used for toolboxes, tackle boxes and on-the-go sharpening, but are generally not recommended for regular sharpening jobs.
Ceramic sharpening stones were the early replacement for natural stones. Unfortunately there are huge differences in the quality of ceramic stones so be wary. Some are extremely soft and dish out very quickly and at the other end of the spectrum some are so hard they tend to glaze over in a hurry. Ceramic stones need a good soaking for about 10 or more minutes to saturate the pores of the stone prior to use. As all knife steels are different we tend to find that ceramic stones tend to work better with some knives over others. There are no hard and fast rules but we like ceramic for Ao-ko and single edged knives. The Kaiden Ceramic stones are the fastest cutting Japanese stones in Australia and are recommended for advanced users.
"How do I use this daunting metal rod?" I hear you ask. Well, it's not too hard, really. The best way for a beginner is to balance the steel on a surface with the tip secured by a damp tea towel. You want to get that angle right, whether it's around 15 degrees for a Japanese knife or 20 degrees on a German or French blade. Then swipe slowly down, away from you, making sure the whole blade is honed – around five swipes on each side should do. 
The 8,000 grit Kitayama is definitely a popular 8K stone, it is my favourite, and the feedback has much to do with that. It is silky smooth and feels creamy when you use it. When reaching refinement levels of 6k and above, polished bevels/edge are inevitable, and often sought after. The level of polish from this particular stone is very beautiful, assuming that you have done some refinement prior to this but it is a wonderful 8,000 grit stone.
Besides of the quality, of course, there are other things to consider when shopping a proper whetstone that would meet our needs that are relating to the type, size of the stone, and the stone grit grade. Nevertheless, it is impossible to recommend which model or type is best for every sharpener because everyone comes with different needs and requirements. The only need-to-know by beginning sharpeners are the basic things that will help them to narrow down their consideration. If it is you, read on our sharpening stone buying guide to find out some basic needs you have to pay attention before spending any penny on it.
Sharpening is really two processes: Grinding and honing. Grinding is simply the removal of metal. Honing is a precision abrasion process in which a relatively small amount of material is removed from the surface by the means of abrasive stones. Once you have the right shape, usually using a more aggressive grit, you then switch to a finer grit to hone the edge.
I recommend keeping two stones in your kit. One with a medium grit (around 800 or so) to perform major sharpening jobs, and one with a fine grit (at least 2,000) to tune the edge to a razor-sharp finish. For real pros, a stone with an ultra-fine grit (8,000 and above) will leave a mirror-like finish on your blade, but most cooks won't notice the difference in terms of cutting ability.

When starting out sharpening, it won’t be long before you hear about the “toothy” vs “polished” edge. It will suffice to know that a 1k stone is going to give you an edge that will perform beautifully as will a knife finished at 5k. There is a belief that a knife that has a highly polished finish, 5k and up will be so polished that it’s toothy goodness will be erased. This knife will not bite into the skin of a tomato for example because the edge is too polished, it will slide over the top. This is not always true, if the knife has been sharpened well, i.e. if Side A and Side B of the blade meet precisely at the Apex of the knife, that edge will slide into a tomato quite beautifully. I have seen many brand new Japanese knives with highly polished 8k edges that no tomato skin can stand up to.

It is better to understand the difference in sharpening stone materials before you are going to make any decision. Among the available options in the market today, Waterstone, oilstone and diamond stone are the most common type of sharpening stone. Each of stones comes with advantages and disadvantages. Waterstone and oilstone are available in natural and synthetic models. Synthetic are the most common and easy to find as man makes them. As the use of natural stones (e.g. original Arkansas or Japanese natural whetstones) is has diminished in popularity, they are beginning to rare in the market. Artificial stones have a more consistent particle size and controlled with a tight mechanism in providing high-quality sharpening stone.
The Sunrise Pro doesn’t have the pedigree of some other knife sharpeners on our list but it performs as advertised and that’s all that matters. For a relative song you get to restore all the knives, steak knives, cleavers in your kitchen to near pristine condition. It’s easy to use and the nice strong suction cup on the bottom means you can put the band aids away.
Today, however, there is a whole new generation of mechanical sharpeners that are far more forgiving for those who may not use perfect technique. At the same time many more people have become accustomed to sharpening their knives this way and the average novice of 10 years ago is now the seasoned pro. It is still possible to damage knives with an electric sharpener, but you would have to either be trying to damage the knife or have some type of accident in order to do so.
The Chef’s Choice 476 2-Stage Sharpener transforms your weary kitchen, hunting and pocket knives into razor sharp cutting instruments with dependable ease. The sharpener is simple in concept, solid in its fabrication and reliable in the way it goes about its business. The design is also free of right-hand bias which is good news for the lefty chefs out there.