Mystery Japanese natural stone speed and finish test.

Hello there.

Some time ago I bought a Japanese natural stone from 330_mate on Ebay. I paid only 20£ so it was a bargain. Unfortunately there was one condition. I couldn't choose stone so I bought a pig in a poke. Some time later I had my stone. My first impression was bad. I tried to sharpen a knife on it but it was a dull knife so I really don't know what I was expecting. I asked some people from Kitchen Knife Forums to help me identify this stone but it is really hard to do that when you only look at the stone. I asked seller to tell me something about it. He told me that strata is central Tomae and it is Mid age mine Nakayama Akapin Nashiji red!

Hardness is class 4. Also he added that this is best stone for hard knives and that I am lucky.

It is very confussing because Tomae Strata and Akapin are two different stratas and this is very soft stone from what I have noticed.

Anyway I've put it away and forgot about it.

I remind myself about that stone last week when I was working on Masamoto yanagiba. I used it only for few minutes and I made fingerstone out of it. The results were very good so I decided to try it out.

I polished my Suisin Densyo white#1 yanagiba to white Binsui level. I didn't wanted to make it perfect but only to try it out. There is still a lot of JNS1000 scratches.

Yesterday I couldn't resist and I have used fingerstone on half of the blade. Results were great. This J-nat is leaving very nice contrast between jigane and hagane.

Here you can see scratches from JNS1000 and Binsui.

I have recorded short movie where you can see speed of that stone.

And finish after it:

So now it is a time to use fingerstone. As you can see on this video it started to create mud after few strokes. It became darker and darker very quickly.

Then I took some very small chips of mystery stone and Uchigomori and ground them in mortar.

Then i mixed it with water and using felt polished the blade.

I think that results are great. I bought that stone for 20£ on ebay and I didn't know what I am going to get. This stone is polishing very fast and it removes scratches very quickly. I can't say much about edge it leaves because I didn't have occassion to use sharpened knife but I will definitely try it out. The finish I have left on that knife is not perfect but as I said before I didn't try to make it nice. I think that next time I will try to achieve great results.