Tomae Natural Japanese Whetstone
Each natural whetstone is different, unlike synthetic whetstones, with variations in size, grit, and overall shape. These stones are all from the Sho-Honyama mines in Kyoto. Tomae is the name of the sedimentary layer that these stones have been mined from. The name of the mines is labeled on the upper right-hand corner and on the left bottom corner the name of the sediment layer is labeled. These layers are two hundred million years old.
These stones are super finishing stones. Since they are natural stones, they don’t have a specific grit number, but it is between #10000~#20000. You can select a stone from the currently available “Types”, the higher the type-number the higher the quality of the stone. Quality is not measured by grit alone, but several factors including the size, the number of inclusions in the rock (small inconsistencies in the grit), overall shape, general condition and naturally the grit.
These stones are typically used at the end of a sharpening/polishing progression. Our advice is to invest in a good set of synthetic whetstones ranging through #400, #1000, #3000, #5000-#6000 and #8000. You would progress to this finishing stone after a #6000~#8000 whetstone.
These stones are essentially "splash and go" and should NEVER BE SOAKED. Soaking these stones can destroy them as water can get between the sedimentary layers and cause the stones to fall apart. Traditionally in Japan the base and sides of the stones are painted with a sealant called cashew lacquer to help maintain the stones. Each of our stones have already received a thin layer of this lacquer and can essentially be used straight away, but it is advisable to add an additional coat or two.
In practice a dressing stone is used with a small amount of water to build up a slurry, the slurry is what polishes the knife. It is preferred to use a natural dressing stone, but you can use a synthetic one. From time to time we are able to secure these natural dressing and when possible we will include one for free with any natural whetstone purchase.