Hakka Tomae Japanese Natural Stone finish compared to synthetic stone finish
In this video I demonstrate the Hakka Tomae, a stone available in limited quantities at Chefknivestogo.com These stones are imported by me (Precise Sharpening) for Chefknivestogo and are stamped (on the back of the stone in this instance) with the Tanaka Toishi Kyogyosho stamp, assuring you of a quality and authentic product.
The mine it comes from is the Hakka mine and the particular layer is the Tomae layer, a more uniform and less stratified layer than the suita layer.
Because the stone comes from a mine and layer I am familiar with I already know the characteristics of this stone even before using it. You will hear comments to the contrary that each stone is a complete mystery grab bag. I describe the stones characteristics before use and, of little suprise to me it performs as expected.
It absorbs water somewhat slowly, although adding more water from time to time is necessary. It is a muddy stone, unlike many other polishing stones, so it is particularly suited to single bevel knives like yanagis or usubas that require a refined edge and don't usually have a perfectly uniform front bevel. It is also well suited to double bevel knives like this Moritaka that has been ground to a zero grind - with no separate bevel but just the two sides of the knife meeting with just a slightly convex grind - not quite a full traditional hamaguri grind.
With continued sharpening, a continually refined mud is being built. I look at the edge as the process continues and a natural stone finish gradually replaces the initial synthetic stone finish, providing a contrast between the softer cladding steel (jigane) and the harder core steel or hagane, with the softer cladding producing a softer sand blasted hazy finish and the harder steel showing a type of mirror finish much like an antique mirror with a black haze. This is referred to as a kurobikari finish.
This is true with any muddy stone - and is used purposely to blend bevels, deal with irregular surfaces and so forth. It is particularly useful for irregular surfaces commonly seen on many single bevel knives. It is a stone almost exactly the opposite of an Ozuku Asagi which is extremely hard and would give precise bevels and microbevels, but 'skip' areas that aren't perfectly coplanar. The mud from the Hakka Tomae is very consistent and pleasant to work with.
In the first video I demonstrated the difference between a synthetic stone finish and a natural stone finish. To those that closely observed the finish some coarser scratches were observable. Some have mistaken these scratches as being from the Hakka Tomae. I would remind you that this is not a coarse stone but rather a polishing stone that neither can remove such coarse scratches nor cause them.
So I went back, going back as coarse as a 400 grit stone up to a 2000 grit stone to remove the majority of these scratches and redid the finish with the Hakka Tomae once again, this time more fully demonstrating the capabilities of the stone itself.
In this video I finish the final stages to demonstrate the Hakka finish without the distracting coarser synthetic stone finishes.