Stones

Brand: Hitohira ひとひら (一片)
Producing Area: Kyoto - Japan
Appearance: Asagi backdrop with numerous Aka Renge 
Width:70mm
Length: 193mm
Height: 18.7mm
Weight: 583g
Grit Range: 6000-8000

1-5 Scale: 1 = Less, 5 = More
Hardness Level: 4.5
Scratch Depth: 1.5
Speed: 4
Wear Rate: 1.5
Self Slurry: 2
Ease of Use: 3.5

Recommended Usage: Fast, bright Kasumi or polished Hagane (Ha-to?); scratch removal from sub 6000 grit; final pre polisher; push cut tools; Uraoshi sharpening; microbevels.

Notes: Amazing value, super consistent specimen. Provides a very fast and easy bright Kasumi. A little harder than more expensive Uchigumori, so be mindful with pressure. Hard enough for push cut tools. The line can only be felt with the fingers when actively feeling for it and not when polishing wide bevels, and it has no effect on the result. A really awesome option for those who want to try their first Uchigumori.

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: Imanishi 今西製砥
Product Type: Flattening Stone
Size: 208 x 68 x 33mm
Weight: 847g

For all of your stone flattening needs!

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: 
Appearance: Near-pure white with the faintest tint of green; a few goma speckled in 
Size: 205mm x 60mm x 38mm
Weight: 901g
~Grit Range: 1500-3000

1-5 Scale: 1 = Less, 5 = More
Hardness Level: 3.5
Scratch Depth: 2.5
Speed: 4
Wear Rate: 2
Self Slurry: 2
Thirst: 2
Consistency: 4.5
Feedback: 2.5
Ease of Use: 3.5

Notes: Koma Nagura stones are a staple in traditional sword polishing progressions—and are often used in razor and fine tool sharpening as well. Pure, high-quality examples like this are increasingly rare, and we’re fortunate to have sourced one. Typically used after Chu Nagura and before Uchigumori, Koma plays a crucial role in refining the foundation polish, allowing Uchigumori stones to fully express their potential. This particular stone is fast-cutting, with black slurry forming in seconds, and it effortlessly removes scratches even from stones more than half its grit level–a polisher dream!

It finishes with a warm, frosty kasumi that’s both beautiful and distinct. Working the jigane for just a few minutes can start to reveal banding, offering exceptional visual depth. Initial feedback has a bit of texture and grip, which quickly smooths out as slurry builds. It’s also hard enough to handle push-cut tools and even Ura on single bevel knives. Obviously effective on knife edges, but given its rarity it is advised that it be mostly reserved for polishing or wide bevel applications. For faster cutting and more even feedback, using a nagura, preferably a tomo nagura, could help. 

Simply put, this is an incredible find for anyone building a premium polishing progression—or a collector seeking something truly special.

Recommended Usage: Pre polisher, frosty kasumi, gnarly edges, push cut tools

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: 2500-4000

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.

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 
Mine: Hideriyama 
Strata: Suita
Appearance: Asagi green with streaks of Namazu
Size: 2,567g
Weight: 238mm x 75mm x 73mm
~Grit Range: 3000-5000

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

Notes: An extremely rare vintage Hideriyama Suita, especially in this large format. A true pleasure to use — it offers silky feedback with a slurry that develops quickly and yields an exceptionally consistent scratch pattern. The resulting kasumi finish is warm and rich and can be achieved with ease and speed. Depending on your approach, you can stop early for a hazy-to-frosty kasumi, or continue on in your polishing sequence for a brighter finish.

Thanks to its generous surface area and substantial thickness, this stone will provide years of use. However, as it’s not particularly hard (though not overly soft either), it’s important to work the surface evenly to avoid localized dishing. It’s likely too soft for push-cut tools, but perfect for wide bevel polishing, even convex grinds.

This is an outstanding stone for collectors due to its rarity, quality, and vintage provenance. While best suited for intermediate to advanced users, its forgiving nature also makes it accessible to mindful beginners.

Recommended Usage: Hazy to frost kasumi, pre or pre pre polisher, convex grinds, refined but textured edges.

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
Producing Area: 
Mine: Natsuya
Strata: 
Appearance:  Classic Natsuya 
Size: 210mm x 80mm x 62mm
Weight: 2767g
~Grit Range: 2000-4000

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

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 longer knives like Yanagiba or large Gyuto. 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 hard firm enough for large planes or chisels. They are also very beautiful.

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

Please note: These pictures and measurements are examples. Individual items may differ slightly in appearance and measurements. 

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.

Please Note: These pictures and measurements are examples. Your specific product may differ slightly in appearance and measurements.

"Base" series; Does NOT include base

Please Note: These pictures and measurements are examples. Your specific product may differ slightly in appearance and measurements.

Flattening Stones

Although all NSK stones are very wear resistant, these flattening/dressing stones are specifically formulated to counter the wear resistance and flatten at an impressive speed. They also work very well on natural stones as well, and the higher grit flattening plates will leave a scratch-free surface unlike many other diamond plates. The flattening stones are slotted to eliminate suction when rubbing against the sharpening stone.

If needed, coarser flattening grits can initially be used on higher grit sharpening stones to remove material quickly, as long as you condition the surface of the sharpening stone with a higher grit flattening plate before use in order to prevent overly-aggressive surface. Each grit of the flattening stones can be used on several different grits, so there is no need to get every single flattening grit for each corresponding grits of NSK sharpening stone you may have; see recommended grit ranges for each flattening stone below.

Flattening grits: 200, 400, 600, 1000, 3000, 6000

Recommended Use: Flattening grits from 200-1000 can be used on All NSK sharpening stones up to 1500 grit. All NSK sharpening stones with grits above 1000 should ideally be flattened with a grit as close to the stone's grit as possible. For example, a 3000 grit sharpening stone should be flattened with grits 3000 and above.

Brand: NSK
Length: 200mm
Width: 75mm
Height: 17mm
Weight: 468g
Grit Range: #3000

Flattening Stones

Although all NSK stones are very wear resistant, these flattening/dressing stones are specifically formulated to counter the wear resistance and flatten at an impressive speed. They also work very well on natural stones as well, and the higher grit flattening plates will leave a scratch-free surface unlike many other diamond plates. The flattening stones are slotted to eliminate suction when rubbing against the sharpening stone.

If needed, coarser flattening grits can initially be used on higher grit sharpening stones to remove material quickly, as long as you condition the surface of the sharpening stone with a higher grit flattening plate before use in order to prevent overly-aggressive surface. Each grit of the flattening stones can be used on several different grits, so there is no need to get every single flattening grit for each corresponding grits of NSK sharpening stone you may have; see recommended grit ranges for each flattening stone below.

Flattening grits: 200, 400, 600, 1000, 3000, 6000

Recommended Use: Flattening grits from 200-1000 can be used on All NSK sharpening stones up to 1500 grit. All NSK sharpening stones with grits above 1000 should ideally be flattened with a grit as close to the stone's grit as possible. For example, a 3000 grit sharpening stone should be flattened with grits 3000 and above.

Brand: NSK
Length: 200mm
Width: 75mm
Height: 17mm
Weight: 468g
Grit Range: #600

Hakuto

Medium hardness, they are ideal for creating softer bevel changes and finishing full convex grinds. Given the available grits are only medium to high grit, Hakuto 1 stones are best left for use after initial, coarser work has been completed. 

Recommended for advanced users.

These thin (2.5mm) options are more affordable than the standard thickness (3.5mm) but will still sharpen for a very long time.

Brand: NSK
Length: 200mm
Width: 75mm
Height: 22mm
Weight: 610g
Grit Range: #10000 

Kyokuha

The original NSK Kogyo diamond stone series, Kyokuha are built for ease of use and compatibility with a wide variety of steels from carbon, stainless, powder, even tool steel. It has a large selection of grits to fit almost every user's needs. These are the softest of the NSK series and probably easiest to learn sharpening and polishing.

Recommended for beginners and seasoned users, or those who simply prefer softer stones.

Brand: NSK Kogyo Ltd.
Grit Range: #1000
Length: 200mm
Width: 75mm
Height: 26.5mm
Weight: 740g

Kyokuha

The original NSK Kogyo diamond stone series, Kyokuha are built for ease of use and compatibility with a wide variety of steels from carbon, stainless, powder, even tool steel. It has a large selection of grits to fit almost every user's needs. These are the softest of the NSK series and probably easiest to learn sharpening and polishing. 

Recommended for beginners and seasoned users, or those who simply prefer softer stones.

Brand: NSK Kogyo Ltd.
Grit Range: #10000
Length: 200mm
Width: 75mm
Height: 26.5mm
Weight: 740g

Kyokuha

The original NSK Kogyo diamond stone series, Kyokuha are built for ease of use and compatibility with a wide variety of steels from carbon, stainless, powder, even tool steel. It has a large selection of grits to fit almost every user's needs. These are the softest of the NSK series and probably easiest to learn sharpening and polishing.

Recommended for beginners and seasoned users, or those who simply prefer softer stones.

Brand: NSK Kogyo Ltd.
Grit Range: #200
Length: 200mm
Width: 75mm
Height: 26.5mm
Weight: 740g

Kyokuha

The original NSK Kogyo diamond stone series, Kyokuha are built for ease of use and compatibility with a wide variety of steels from carbon, stainless, powder, even tool steel. It has a large selection of grits to fit almost every user's needs. These are the softest of the NSK series and probably easiest to learn sharpening and polishing. 

Recommended for beginners and seasoned users, or those who simply prefer softer stones.

Brand: NSK Kogyo Ltd.
Grit Range: #3000
Length: 200mm
Width: 75mm
Height: 26.5mm
Weight: 740g

Kyokuha

The original NSK Kogyo diamond stone series, Kyokuha are built for ease of use and compatibility with a wide variety of steels from carbon, stainless, powder, even tool steel. It has a large selection of grits to fit almost every user's needs. These are the softest of the NSK series and probably easiest to learn sharpening and polishing.

Recommended for beginners and seasoned users, or those who simply prefer softer stones.

Brand: NSK Kogyo Ltd.
Grit Range: #400
Length: 200mm
Width: 75mm
Height: 26.5mm
Weight: 740g