Shigefusa 270mm kasumi yanagiba with custom, by me, desert ironwood handle

11 Mar 2011

Nakayama?? Karasu - A lot of power in a small package #8-15000

In view of some of the comments to my latest post regarding the Aka-pin stones, I am not sure if I dare to describe this stone as a Nakayama, even if it looks very similar to other stones on the Internet stated to be Nakayama karasu and as it was was sold to me as one. I will thus merely call it a Karasu stone, and that it definately is! I have previously reviewed another one of my karasu stones here:

This little beauty might very well have a different origin than Nakayama. However, the origin is of merely academic interest to me as the real purpose of my stones is to sharpen my knives, kanna and chisel to a useable level. Actually most of my knives are way sharper than just useable, due to me sharpening them a lot more than strictly required.

This particular little stone was one of my first Japanese natural stones, and even after trying a magnitude of different stones this little beauty has earned its place in my setup as one of my absolute favourites. It is fairly hard, maybe around Lv4, very efficient and exactly the perfect grit range for most of my kitchen knives, leaving a nice mist and haze on my kasumi blades and a very keen edge with just the right amount of bite to it. Karasu can also be fairly soft and Maxim at japanesenaturalstones have a very nice and soft one that I hope to experience one day.
A beautiful stone alltogether. I love it!

Small and thin but very clean and free of cracks

Beautiful karasu like a modernist painting. A true gemstone.

The board is light grey with spots of greenish to yellowish in it and with a dense karasu pattern showing a shine in the dark mica in the stone making the karasu so efficient as a sharpening stone. I looks like it has got a perfect camouflage. It also shows some nashiji pattern enbetween the black karasu. This stone has really got it all.

The white lines in the board looks almost like paint spill on the stone and is close to the same hardness as the rest of the stone and thus of absolutely no consequence to the sharpening.

When sharpening, the stone pulls black metal filings immediately proving that this is a very efficient and fairly hard stone. You can see the metal filings suspended in the clear water before a slurry has built. This is usually a good sign, but it is no guarantee for the stone being a good sharpener or finisher. It is just a proof that the stone removes metal, which is only one of several things a good stone will have to do.
Black metal filings suspended in clear water = extraordinary efficiency.
After about 50 strokes on the stone, a dense dark olive slurry builds, making the sharpening experience a lot smoother and creamier. Not that the stone is scratchy. It isn't, but the feel of the stone changes as a slurry builds up. The stone is not very thirsty and the slurry holds up for a long time befor I have to add water to it. This provides for a very consistent result as I can concentrate on the sharpening and not consistently add water to keep the slurry within my comfort range.
Dense dark slurry building up
When looking at the finish, you can still se a few very light scratches, mainly in the soft steel jigane. This might be a result of poor ground work or me being a little bit too impatient. The edges off this stone, however, is some of the keenest edges I am able to produce on my knives. Especially on regular kitchen knives like my gyuto, nakiri and santoku. Exceptionally sharp but still with a very nice bite to them making the knives a pleasure to use both on proteins and veggies. It is a highly versatile stone handling all the types of steel I have thrown at it equally well, from soft 440C to blue #1 honyaki. That is an unusual but highly desireable feature for a japanese natural stone.
Not a high polish finish, but a very keen edge
From my experience it seems to me that karasu stones are generally efficient sharpening stones. However, I have heard that karasu stones, like asagi, can be quite scratchy and produce poor results if used unwisely. If you can find a good one, it should be a part of any Japanese natural sharpening stone set-up, but as these beauties are becoming quite rare you will probably have to expect a high cost. I really love this stone. It looks beautiful and is an excellent performer. My only whish is that it was a little bit thicker, but a full size stone of this quality would be dramatically out of my reach pricewise if at all available.

However small, this little stone is an absolute pleasure to use and one of the very few true gems in my collection. As it is a fairly hard rock, hopefully it will last a long time.



  1. Another great review... i agree on the issue of the mines, etc. As long as the stone does what you want, who cares. Looks like a great find. I havent had as much luck with karasu. They cut very fast, but i've only been able to find super hard ones. Maybe 30-40% of the ones i've tried were scratchy, the rest were very nice a smooth... but fast. Maybe one of these days i have to track down some softer karasu like Maxim has. They could be fun.

  2. It have to be clear when you say scratchy what it means many think it have some impurities when people say scratchy but it is a big misunderstanding, scratchy can be 2 things, one is where it have some impurities and you have to dig them out, another is when stone is to hard for given steel and particles from stone scratch the soft steel , it is seen a lot on kasumi knifes with soft steel cladding but it will works very good for all steel knifes or honyakis but very slow because they are so fine but the best they are on razors where they really shine :) So my point is that they are not many bad stones, there are bad purpose for the stones.

    Harald you stone looks amazing and it looks very clean very good score you got there also very nice review:)
    For softer karasu look for more gray color with more whitish they tend to be softer where very black and dark color will be much harder hope it helps

  3. What you say make a lot of sense (as usual). In this particular stone I beleive the stone might be on the hard side for the soft jigane and that this makes it scratchy until a slurry has built. In addition there are very pronounced spots of mica in the stone which makes the stone very agressive but may give up scratchy particles which may scratch the softer jigane even when working on slurry. I will be more specific about this in the future. Thanks :o)

  4. Nice review Harald!

    A comment about thin stones.
    Many Jnats stone collectors with experience in Japan are looking for thin stones.
    Not because thinner stones are cheaper.
    The chance you find a gem stone is bigger.
    The logic is that smaller sediments will take longer time to grow. So the layer of very fine stones are thinner.