All natural stones in our store have been thoroughly tested by me on Razors, Knives, and Tools. Japanese natural water stones no longer available! The main downside of natural Novaculite stones are that they cut slower. In contrast, the most common natural Japanese whetstones are made from sedimentary rock. Cookies we use, Other Sharpening Stones, Honing Guides, Accessories. Use can use any waterproof lacquers or simply glue it to wooden or other bases. Ozuku natural sharpening stones "Koppa" shape, Western mountains: Ohira, Shinden, Mizukihara, Eastern mountains: Nakayama, Ozuku, Kizuyama, Okudo, Shoubu, Narutaki. I have included a short description with each stones relative hardness and best use. IMPORTANT note for All Sharpening stones, Synthetics or Naturals, Seal all your stones that way you are 100 % sure that they hold a life time ! Japanese Natural Stones. These stones are mined in the Narutaki District near Kyoto and are well regarded by professionals. Nakayama Asagi Maruichi Kamisori Lv 5+ (a2109), Takashima Kiita "Ooban" HUGE Lv 2,5 (a2012). If a stone has any inclusions or toxic lines, it will be stated in that particular stones description, otherwise there are none. Selected Japanese natural sharpening stones Toishi, Handmade by Best Blade smiths Japanese Knives, Razors and Tools Japanese natural sharpening stones are becoming scarce because many of the mines are exhausted after centuries of quarrying them. The water in the stone will freeze and expand, damaging or cracking the stone. Please email me before buying a stone, and I will try and guide you to which stone suits you and your situation the best. Japanese Natural Stones. IMPORTANT note for All Sharpening stones, Synthetics or Naturals, Seal all your stones that way you are 100 % sure that they hold a life time ! The upside is that they cut better, meaning they will sharpen knives faster. Storing the stones – wet or dry: in Japan natural sharpening and honing stones are normally stored dry and out of the sun after they have been flattened and the grit paste has been removed. The resulting whetstone is softer and wears down faster than your typical Novaculite stones. They should never ever be exposed to freezing temperatures when wet. All natural stones in our store have been thoroughly tested by me on Razors, Knives, and Tools.