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Tanaka Toishi

Tanaka Toishi Umajiyama Natural Stone Type 100 #5

Regular price
€199,00 EUR
Regular price
Sale price
€199,00 EUR
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Umajiyama, a mine located next to Ohira. Lesser known but producing excellent stones. We get these in different sizes from Tanaka Toishi in Kyoto. Indicated by ‘type’, the lower the number, the bigger the stone.

In general these Umajiyama can be characterised as easy to use, good for polishing and for edge. Some might be a little softer then others, mostly ranging between 2-3. They are surprisingly fast cutters with a grit range from 3-5k and a good amount om self slurry ability.

The finish I would describe as Kasmui-like, no heaps of contrast but a more misty shiny finish. Very satisfying on its own or as pre-finish for higher grits. Edge finish is refined but with a decent amount of toothyness
Great first natural stones for beginners of advanced.

About Natural Stones

Natural stones, or JNATS or Tennen Toishi are natural sharpening stones quarried in various mountains in Japan. Made by natural thanks to Japan’s rich sedimentary and geological history. Japan is one of the only countries where such a diverse amount of silica and aluminium oxide rich stone can be found. These two elements give the stones the ability to cut steel in an effective way. The presence of natural sharpening stones is what gave Japan its history of swords and high quality tools. They have incredible historic and cultural value and the world of naturals is as complicated as it is fascinating.

Tennen Toishi can produce result unmatched to any man-made sharpening stone. They last longer, make better edges and can produce amazing polishes.
Rated on size, hardness, fineness, evenness and cutting speed with large, fine, fast and clean stones often being the most desirable.
It is difficult to generalise but some mountains or mines are known to produce certain characteristics. With known origin and layer one can form suitable expectations but each stone should be tested individually.

Jnats are slash ‘n go stones and do not need soaking. Often you’ll see that the high quality stones are sealed with urushi lacquer, or even glued on a little wooden board or stand. This is to provide extra strength since natural stones can be fragile. Do not drop ‘m and seal or support them if not done already.
On this website natural stones are rated with a 1-5 score for hardness, fineness and cutting speed, 5 being hardest, finest and fastest. Weight and dimensions you will also find below.
Natural stones are divided into three groups: Aratoishi (coarse), Nakatoishi (medium) and Awasedo (fine). The rating applied is relative to the category of the stone. A 3/5 fineness Nakatoishi is not as fine as a 3/5 Awasedo.


Detailed Spec

Brand: Tanaka Toishi 田中砥石工業所
Product Type: Natural Stone
Size: Type 100

Weight: 543gr
Mine: Umaji
Producing Area: Kyoto/ Japan
Hardness (5 = Very Hard) : 3
Grain Scale (5 = Very Fine) : 4
Sharpening Speed (5 = Very Fast) : 2+

*Please understand that all pictures on our website are made of random samples and as most products are made with natural materials by hand the color, appearances and even measurements can slightly vary. Please contact us if you wish to see the exact item we have on hand.