Japanese Natural Waterstones - It wouldn't be an exaggeration, to say that they're the most respected, mystified and complicated sharpening devices out there. For now, this section is just a short description, plus mini reviews of what I have. As such, it will be a shorter section. If I had enough time and more importantly, knowledge, perhaps I could devote separate site to this topic. Japanese natural whetstones are treated with tremendous respect amongst Japanese and western knife experts and enthusiasts. I've seen stones for sale that are over 50 or even 70 years old. I've heard stories about famous stones passed on through the generations. They're trully treated as sacred items. If you are into whetstones and know what they're about, then you understand it.
As it is the case with any natural resource, quality whetstones are scarce, hard to obtain and therefore, pricey. Paying several hundred dollars for a good stone is nothing unusual, and really good stones cost several thousands apiece. Another problem is getting a good stone. Just the high price alone won't guarantee top performance for your multi thousand (or hundred) stone. Best is to shop with the trusted source. So, as usual you need to research, aks around and all that.
There are different types of stones, that is besides the grit. The highest grade stones are mined in quaries aroud Kyuto. The trouble is, most of those quaries are closed. Some have been closed over 30 years. As far as I understand, couple of those cloased quaries were reopened during last few years. Still, demand clearly is higher than the supply, thus the extremely high prices. I'll put separate page together for stone types and quality information. Whatever is scattered through the web is really disconnected and unorganized. At least for non Japanese readers.
Synthetic Whetstones- When there is a demand to fill, which can't be filled by natures resources, technology comes forward. So, we have synthetic whetstones(waterstones). At this moment majority of my whetstones are synthetic, although I am working on replacements. By the way, it's not always clear win for the natural stones, at least for the low grits. As far as I can tell, based on the input of more experienced sharpening experts, below 1000 grit, which would correspond to ~18µm particle size, synthetics are preferred. They last longer and wear out slower. Obsiously, synthetic stones are much cheaper compared to natural ones. Downside is their rather low water absorptioncapacity compared to natural stones. In other words you have to spray water on the much more often during the sharpening process. For higher grits, especially above 8K, natural stones are much better choice, and much more expensive. But they perform better in all aspects. Natural whetstones hold more water, cut faster and resulting finish is smoother. Obvious downside is the price, where the difference is level of magnitude.
IMHO- So far I dont' have much of an experience with natural whetstones, but I do have respect for them and after using my Aoto I love it. Performance and the feel of it is very different compared to synthetic whetstones. I really like them, for their speed and final finish quality even if they're messy. Currently I have 220, 500, 700, 2000-3000 and 12000 grit stones. The gaps in grits are filed in with abrasive films as necessary. Final finishing is done 0.5µm Chromium Oxide(CrO) and 0.25µm Diamond Spray loaded strops. Those are correspondingly 60 000 and 100 000 grit.
Last updated - 01/23/12