# How can you identify the grit of a Japanese water stone?



## SirTonka (Jul 27, 2013)

Looking for knowledgeable advice on a few used Japanese water stones I picked up recently.
Purchased the set from a widow of a local 3M engineer, she told me her husband had traveled several times to Japan in the past. The light tan and dark stones look natural, the reddish brown stone possibly is synthetic. 
This is my first stone set, have been using diamond plates mainly. Planning to purchase a few more stones and would like to know what will be needed and where each stone's place is in the sharpening order.

How can I test to find out the grit?

What attribute should I look for that indicates the stone's maker?

Any advice or experience comes to mind that you can share?























































Let me know if any other images detailing the stones are needed.


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## Loren (May 30, 2008)

You may be dealing with some exotic stones. Pieces of
metal may be polished on the stones and the scratch
patterns assessed under a microscope or jeweler's loupe.

http://www.japanwoodworker.com/category/13119/natural-stones.aspx

The reddish synthetic stones tend to be in the 800-1200 
grit range from what I've seen.


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## SirTonka (Jul 27, 2013)

Loren, thank you for the grit range on the red stone. 
Working with the two naturals today. Searched through japanwoodworker, no match found.
Hope someone fluent in Japanese can translate the text and provide insight on the dark stone.


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## chrisstef (Mar 3, 2010)

From another web source:

I think the K-45 is just the stone model and not the grit number. I have a few King stones and noticed they seem to use a color scheme that goes like this:

Rough stone:
Black is usually less than #100
Green is the #220

Medium: Usually brown: 800, 1000 and 1200

Fine: beige 3000, 4000

Polishing: light yellow or cream 6000 and 8000.


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## Loren (May 30, 2008)

I recall some blue quaried stones being available in some catalog a
while back… maybe Garret Wade… so I googled and
came up with this:

http://www.epicedge.com/shopexd.asp?id=87267


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## Loren (May 30, 2008)

SO my guess is the red stone is the coarse stone, blue medium
and the cream stone the finishing stone. The little stone
may be a nagura.


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## planeBill (Oct 21, 2011)

You need to send them to me. ;-)

They all look like naturals to me. The cream one for sure, the blue looking one in the third pic looks to be an ayoto, the one in the forth pic has the saw marks so it has been quarried and cut, the small one is a nagura stone. As far as grits go, that's will be hard to pinpoint but using them and examining the scratch patters under a loup at least will give you an idea of the class of stone, finish, polish etc.
There are people out there far more knowledgable than I, Stuart Tierney and So Yama********************a come immediately to mind. Their websites are Tools from Japan and Japan tool respectively, They may be able to help you.
If you cant find out anything, you can always send them to me, I'll take them off your hands.


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## SirTonka (Jul 27, 2013)

chrisstef, nice color scheme list, a useful reminder.

Loren, Got back from working on the red stone. The surface took time to lap and when honing the grit felt like it was not letting go from the stone. Hard surface yet scratch looked rougher than my DMT coarse. That link looks mighty close to the dark stone, minus the saw cuts. Thanks again.

planeBill, Red is a natural? Would chips be from usage or evidence of being a natural? 
The 3rd and 4th pictures are of the same dark stone, positioned for a new angle. 
To my eye the nagura is similar stone to the dark natural. And thank you for the recommendations.


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## planeBill (Oct 21, 2011)

Maybe Im a little thickheaded. I see a cream colored stone that is a natural. I see a reddish-purpleish stone and a blueish stone with the saw marks. OK, well, maybe the reddish stone is a mystery but I know the cream colored stone is natural and as far as the blueish(my monitor) Ive never seen a synthetic stone with single tooth saw marks on it.
As far as the red stone goes, I only know of two synthetic stones that approximate that size, the red brick and the green brick. It aint green. Again, I am not a know it all. Just my meager opinion.


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## SirTonka (Jul 27, 2013)

planeBill, righto

Worked a bevel on a 12mm mortise chisel today. Even with that much metal to hone, both naturals had the metal skating across as if on a fresh file.


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## RonInOhio (Jul 23, 2010)

Interesting thread. Can't offer much except, find someone who is affluent in reading
Japanese. Would think that some of that Japanese writing describes the stones
charactristics.


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## planeBill (Oct 21, 2011)

J-nats are not listed or describes as to grit but to where they fall in the sharpening sequence. Any grit rating assigned to a natural stone will always be a guesstimate.
Did the stone build a slurry? Did it build a slurry quickly or slowly? How quickly did black metal swarf appear? Did it appear at all? What did the surface of the tool look like when you were done?


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## Loren (May 30, 2008)

Try using the nagura to make a slurry.

I've only used clay based (synthetic) stones.

*Marketing hyperbole vs. reality:*

I have a Norton 8000 stone and the claim is that
it just needs a spritz of water to work, but it needs
a good soaking in my opinion to work best… otherwise
you're just rubbing the metal around on what might
as well be a dry stone and the stone glazes.

With a lot of water on the stone, there can be a 
suction effect on tool backs and the tool is hard to
move around. I make a slurry with the nagura 
and this helps mitigate the suction.

I've never used the natural stones, but from my experience
with synthetics, if you're not getting started with soaking
them for 15 minutes your stones may be too dry.


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## SirTonka (Jul 27, 2013)

RonInOhio, I agree, still searching for a translator.

planeBill, have been documenting the process. Posting a full report when finished.

Loren, the nagura gets slurry started in short order. And agree that the stones benefit immediately from a good soaking.


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