NSK Diamond 300A Kyokuha and Flattening Device

The diamond 300A stone is a 300 grit diamond stone.  Unlike diamond plates, these stones are constructed in a manner more similar to normal waterstones.  The top ~5mm of the stone is composed of a hard binding agent with diamond abrasive mixed in.  This is then attached to a taller base, such that the whole item together is about the same size as many of the other stones we sell.  Unlike some diamond stones that use metal or aluminum bases, this base is a lightweight, water resistant plastic, which I have found to be lighter and more convenient to use and care for than other bases.
 
With regard to the stone, we have spent a significant amount of time working with the maker to find the right balance of cutting power, tactile feedback, and resistance to dishing.  Coarse stones tend to get the brunt of work when repairing knives or trying to get through sharpening more quickly.  This stone is rather fast cutting, though it is not particularly muddy.  I use this stone to remove deep 150 grit scratches, which it does with ease, rather quickly.  The scratch pattern it leaves is very consistent and even, and, again, unlike diamond plates with the abrasives plated onto the surface, these stones leave scratches with a depth more similar to regular sharpening stones.  Thanks to their diamond abrasive, they work well on all steel types, including some of the most hard and wear resistant steel.  They can even be used to sharpen ceramic knives.  As the binding agent is not porous, these stones are true splash and go stones.
 
This diamond stone does dish a bit faster than some other diamond stones, which is why we have it in a thicker stock, and also include a special flattening device for flattening these types of stones.  That being said, it still dishes very slowly, and after over a year of heavy use, I have worn through less than 20% of the stone.  As a comparison, in the same time frame, I was able to wear completely through a different type of diamond stone, and multiple ceramic and resinoid-based stones.  When using the flattening stone, work the high spots down by rubbing those areas in a circular motion.