Stones

Brand: Tanaka Toishi 田中砥石工業所
Producing Area: Mikawa Mountain Range, Kitashitara, Aichi - Japan
Mine: Kada Mountain or unspecified Junmikawa stratum
Strata: N/A
Appearance: "Striped" (shima) lines running linearly down the length of the stone, a mix of off-white and orange. Beautiful chalky block!
Size: 220mm x 82mm x 45mm
Weight: 1573g
~Grit Range: 2500-4000

1-5 Scale: 1 = Less, 5 = More
Hardness Level: 3.5
Scratch Depth: 2.5
Speed: 2 (4 with tomo nagura)
Wear Rate: 2
Self Slurry: 2 (4 with tomo nagura)
Thirst: 3
Consistency: 3.5
Feedback: 2.5
Ease of Use: 2.5

Notes: A large, pure nagura that will last many years. 

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

Background Info: Nagura are made of lithified tuff, which is silica-rich stratified volcanic ash that has been compacted into a solid over many, many years, and this composition yields unique sharpening and polishing properties. Much of their use has been centered around blades other than knives: swords, razors, woodworking tools and so on. Nagura can come from several locations in Japan, the most famous being the Junmikawa (Mikawa) mine located within the Mikawa Mountain range in Aichi Prefecture. 

Chu Nagura are used as one of the last stones before Uchigumori in a traditional sword polishing sequence. Such "proper" Chu Nagura are mined at Kada Mountain, not from the Mikawa mine-proper, both of which are in the same mountain range. Chu Nagura can also be somewhat of a catch-all term for stones from the Mikawa mine that do not fit cleanly into the known classified strata. Within swords, "chu" is often used to roughly mean "medium" (medium grit, medium size, etc.)

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.

Brand: Tanaka Toishi 田中砥石工業所.
Producing Area:  Kyoto/ Japan
Mine: Kouzaki
Appearance: Certainly a base of blue, hence the name "Ao"-to, "blue" stone. These softer versions tend to have a tint of red/brown to them, a decent indication of their softness level.
Size: 175mm x 52mm 54mm
Weight: 1031g
Grit Range: ~2000

1-5 Scale: 1 = Less, 5 = More

Hardness Level: 2
Scratch Depth: 4
Speed: 4
Wear Rate: 3.5
Self Slurry: 4.5
Thirst: 3
Consistency: 5
Feedback: 4
Ease of Use: 4

Recommended Usage: Early/mid polishing sequence, hazy Kasumi, textured edges with solid bite.

Notes: This is slightly coarser and softer vs. its finer and harder Aoto sibling. These softer versions will be faster cutting, create more slurry, leave slightly deeper scratches, create darker/hazier Kasumi, and would be used earlier in a polishing progression. Softer stones tend to be easier to use as they are more "forgiving" than harder stones, thus easier to learn on. These are "true" Aoto of quality, consistency, and provenance. Given their price they are an awesome way to get involved with natural stones. 

Disclaimer: 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, weights and measures, and qualities. Stamps may be different or not present, especially if it has been tested.

Brand: Tanaka Toishi 田中砥石工業所.
Producing Area:  Kyoto/ Japan
Mine: Kouzaki
Appearance: Certainly a base of blue, hence the name "Ao"-to, "blue" stone. These softer versions tend to have a tint of red/brown to them, a decent indication of their softness level.
Size: 205mm x 57mm x 55mm
Weight: 1430g
Grit Range: ~2000

1-5 Scale: 1 = Less, 5 = More

Hardness Level: 2
Scratch Depth: 4
Speed: 4
Wear Rate: 3.5
Self Slurry: 4.5
Thirst: 3
Consistency: 5
Feedback: 4
Ease of Use: 4

Recommended Usage: Early/mid polishing sequence, hazy Kasumi, textured edges with solid bite.

Notes: This is slightly coarser and softer vs. its finer and harder Aoto sibling. These softer versions will be faster cutting, create more slurry, have deeper scratches, create darker/hazier Kasumi, and would be used earlier in a polishing progression. Softer stones tend to be easier to use as they are more "forgiving" than harder stones, thus easier to learn on. These are "true" Aoto of quality, consistency, and provenance. Given their price they are an awesome way to get involved with natural stones.  

Disclaimer: 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, weights and measures, and qualities. Stamps may be different or not present, especially if it has been tested.