Natural Stones

One of our most trusted sources handpicks these stones from the famed Imanishi in Kyoto for us, spending hours testing dozens and dozens and selecting only the best of the best at a variety of price points. These tennen toishi represent some of the best value you will find on the market for natural stones.

These stones are so impressive that they often make you feel like you are "cheating", so to speak - they provide outstanding results at a speed seemingly found only in stones that cost many times more, all while being fun and easy to use - they make it seem as if you have learned years of polishing in a matter of minutes. Combining these gems with the correct steel, you will come to understand the beautiful harmony skilled polishers sometimes have difficulty describing - working on natural stones with well-made knives truly ties the whole subject together.

We are proud to provide such wonderful pieces to you!

Brand: Komon-picked Imanishi
Producing Area: Kyoto - Japan
Mine: Hideriyama
Appearance: Classic Hideriyama Asagi with faint Kan and red hues visible when wet
Size: 194mm x 69mm x 29mm
Weight: 911g
~Grit Range: 4000-6000

1-5 Scale: 1 = Less, 5 = More
Hardness Level: 2.5
Scratch Depth: 1.5
Speed: 3.5
Wear Rate: 2
Self Slurry: 4
Thirst: 3
Consistency: 4
Feedback: 2
Ease of Use: 4

Notes: A classic representation of quality Hideriyama - mid-grit that you can work the slurry easily into lower high-grits; smooth, very consistent almost silky feedback; fast with dark slurry showing immediately; firm but on the softer side; and easy to use. A very high quality specimen for the cost and an ideal option for those getting into natural stones given its ease of use - just avoid gouging the surface. The lines cannot be felt and are not toxic.

Recommended Usage: Frosty Kasumi; mid+ step in polishing sequence; general wide bevel work, just firm enough for push cut tools; refined edges with the slightest bit of bite.

Disclaimer: Given the natural aspect of these stones, all graded characteristics are our own subjective thoughts which may vary from your expectations and assessment. The images shown and characteristics described may be from a previous, random example, or when first measured before being tested numerous times. If purchased, yours may differ slightly in appearance and qualities. All stone sales are final.

One of our most trusted sources handpicks these stones from the famed Imanishi in Kyoto for us, spending hours testing dozens and dozens and selecting only the best of the best at a variety of price points. These tennen toishi represent some of the best value you will find on the market for natural stones.

These stones are so impressive that they often make you feel like you are "cheating", so to speak - they provide outstanding results at a speed seemingly found only in stones that cost many times more, all while being fun and easy to use - they make it seem as if you have learned years of polishing in a matter of minutes. Combining these gems with the correct steel, you will come to understand the beautiful harmony skilled polishers sometimes have difficulty describing - working on natural stones with well-made knives truly ties the whole subject together.

We are proud to provide such wonderful pieces to you!

Brand: Komon-picked Imanishi
Producing Area: Kyoto - Japan
Strata: Suita
Appearance: Stunning white and light-gray surface with some small Aka Renge. A large number of visible Su. Some, only one can be very faintly felt but has no negative effects.
Size: 212mm x 80mm x 40mm
Weight: 1614g
~Grit Range: 4000-6000+

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

Notes: A beautiful stone both aesthetically and for polishing results - great coloring effects, leaves a soft transition at the cladding line. A very consistent, easy to use, and very, very fast stone. A very fine black slurry forms pretty much immediately, and a gray slurry when working the whitter spots, and working the slurry further creates an incredibly smooth feedback. Scratches are incredibly uniform and pretty shallow. You could finish on this for a frosty kasumi, or has a really fast pre polisher for something brighter. Pretty much an ideal stone for wide bevels. It feels almost pillowy-soft and has a slightly chalky feedback almost akin to working a Nagura, in fact you could largely substitute one for another. Given its ease of use intermediate users could quickly benefit, but you would certainly find this in a professional polishers arsenal.

Recommended Usage: Pre-polishing, final polish, super refined edges. Could be used for push cuts if used with light pressure. 

Disclaimer: Given the natural aspect of these stones, all graded characteristics are our own subjective thoughts which may vary from your expectations and assessment. The images shown and characteristics described may be from a previous, random example, or when first measured before being tested numerous times. If purchased, yours may differ slightly in appearance and qualities. All stone sales are final.

Brand: Morihei 森平
Mine: Natsuya
Appearance: Classic Natsuya figuring
Size: 210mm x 82mm x 63mm
Weight: 2417g
Grit Range: 2000-4000
1-5 Scale: 1 = Less, 5 = More

Hardness Level: 3
Scratch Depth: 2
Speed: 3
Wear Rate: 2
Self Slurry: 2
Ease of Use: 4

Recommended Usage: Mid grit polishing sequence, frosty kasumi, textured but refined edges, sharpening push-cut tools.

Notes: Natsuya have seen a huge explosion in popularity, largely do to their relative ease of use and availability. They are often cut large, so ideal for wide bevel knives and planes. They are firm but not at all hard. Their grit range makes them useful for both edges or quick Kasumi. Easy enough for beginners and novices. Large and firm enough for large planes or chisels. They are also very beautiful.

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. 

Special selection Uchigumori 

This "museum grade" gem was hand selected for us by the owner of Morihei. It is expensive, it is rare, it is absolutely worth it.

Brand: Morihei 森平
Producing Area: Kyoto - Japan
Appearance: Pristine, classic high-grade Uchigumori pale purple with numerous aka renge. Sealed in cashew lacquer.
Size: 213mm x 80mm x 36mm
Weight: 1428g
Grit Range: 3000-6000

1-5 Scale: 1 = Less, 5 = More
Hardness Level: 4
Scratch Depth: 2
Speed: 5
Wear Rate: 1.5
Self Slurry: 2
Thirst: 1.5
Consistency: 5
Feedback: 2
Ease of Use: 4.5

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.

Disclaimer: Given the natural aspect of these stones, all graded characteristics are our own subjective thoughts which may vary from your expectations and assessment. The images shown and characteristics described may be from a previous, random example, or when first measured before being tested numerous times. If purchased, yours may differ slightly in appearance and qualities. All stone sales are final.

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.

Brand: Tanaka Toishi 田中砥石工業所.
Producing Area:  Kyoto/ Japan
Mine: Kouzaki
Appearance: "Aoto" means "blue stone", thus the blue foundation. Finer examples can be a true solid blue, while some can have subtle hints of purple or green, while softer examples will have more red/brown tones.
Size: 201mm x 57mm x58mm
Weight: 1528g

Recommended Usage: Mid polishing sequence, frosty Kasumi, mid sharpening for push-cut tools, keener edge with a little bite

Notes: This is finer and harder vs. its softer, coarser and generally slightly reder Aoto brother. While finer variants will typically be marginally slower cutting, they will have shallower scratches, last longer, provide brighter Kasumi, as well as be better for push cut tools. So this option will be more ideal for mid work.

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 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, 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.

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.