Natural Stones

*Special selection Uchigumori*

Recommended Usage: Final polisher, pre polisher, sword sequence, push cut tools, edges, microbevels.

Notes: An extremely fast, easy to use, versatile, flawless, premium select piece; one of the nicest stones we've carried. This is one of those stones that make you feel like you're cheating since it makes things so easy. Even a novice polisher can use this to outstanding results. Sealed in cashew lacquer. Will last a lifetime.

Please Note: Given the natural aspect of these stones, all subjective qualities are our estimates and may vary slightly from your exact expectations and assessment. The images shown and characteristics described may be from a previous example. If purchased, yours may differ slightly in appearance and qualities. Dimensions, weight, and stamps may be different from listed if it has been tested. 

Brand: Tanaka Toishi 田中砥石工業所
Dimensions: 220mm x 82mm x 45mm
Weight: 1573g

Notes: Really nice specimen from the famous Mikawa mine in Aichi Prefecture via the famous Tanaka Toishi brand. They are firm to hard, and quality specimens are fast and give good polishing results. Generally easy to use depending on the hardness.

Suggested Use: pre or final polisher for knives and push-cut tools.

Background Info: Nagura is made of lithified tuff, which is silica-rich stratified volcanic ash that has been compacted into a solid over many, many years. They contain very fine particles of silica (and other  which are often more friable than other sedimentary stones, and thus are ideal for polishing. They are used as one of the last stones before Uchigumori in a traditional sword polishing sequence. The word "Nagura" is the named after the individual who discovered the utility of the lithified tuff as a whetstone, Sakon Nagura, over 700 years ago.

Please Note: Given the natural aspect of these stones, all subjective qualities are our estimates and may vary slightly from your exact expectations and assessment. The images shown and characteristics described may be from a previous example. If purchased, yours may differ slightly in appearance and qualities. Dimensions, weight, and stamps may be different from listed if it has been tested.

Brand: Tanaka Toishi 田中砥石工業所
Dimensions: 225mm x 86mm x 44mm
Weight: 1615g

Notes: Really nice specimen from the famous Mikawa mine in Aichi Prefecture via the famous Tanaka Toishi brand. They are firm to hard, and quality specimens are fast and give good polishing results. Generally easy to use depending on the hardness.

Suggested Use: pre or final polisher for knives and push-cut tools.

Background Info: Nagura is made of lithified tuff, which is silica-rich stratified volcanic ash that has been compacted into a solid over many, many years. They contain very fine particles of silica (and other  which are often more friable than other sedimentary stones, and thus are ideal for polishing. They are used as one of the last stones before Uchigumori in a traditional sword polishing sequence. The word "Nagura" is the named after the individual who discovered the utility of the lithified tuff as a whetstone, Sakon Nagura, over 700 years ago.

Please Note: Given the natural aspect of these stones, all subjective qualities are our estimates and may vary slightly from your exact expectations and assessment. The images shown and characteristics described may be from a previous example. If purchased, yours may differ slightly in appearance and qualities. Dimensions, weight, and stamps may be different from listed if it has been tested.

Brand: Tanaka Toishi 田中砥石工業所
Producing Area: Kyoto, Osaka - Japan
Mine: Yaginoshima
Appearance: Classic grey/blue Mizu with lots of teeny tiny Goma
Size: 209mm x 76mm x 40mm (type 40)
Weight: 1567g
Grit Range: 4000-6000

1-5 Scale: 1 = Less, 5 = More
Hardness Level: 4.5
Scratch Depth: 2
Speed: 3.5
Wear Rate: 1.5
Self Slurry: 1.5
Thirst: 2
Ease of Use: 3

Notes: A lovely stone and affordable stone. While it is on the harder side on paper, it was actually difficult (ie we had to intentionally try) to get the stone to scratch our test Kiridashi. The feedback was tackier than expected given its hardness, providing more feedback and reducing the chances of slipping that can occur with harder stones. Again despite its hardness, it is rather fast and creates black slurry after 10-20 seconds. It provides a brighter Kasumi with relative ease, we're rather impressed. For the price it is a good choice for both beginners and intermediate users despite its hardness. Its dimensions and hardness will make it last many years.

Recommended Usage: Keen edges, polishing for frosty to bright Kasumi on wide bevels. Very good for push-cut tools.

Please Note: Given the natural aspect of these stones, all subjective qualities are our estimates and may vary slightly from your exact expectations and assessment. The images shown and characteristics described may be from a previous example. If purchased, yours may differ slightly in appearance and qualities. Dimensions, weight, and stamps may be different from listed if it has been tested.