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

10 May 2011

Mystery stone - a nice pre finisher for kitchen knives #6-8000 Lv3 - 3,5

I frequently browse the Internet for japanese natural stones in my quest to learn new things about them and maybe find the occasional bargain. It is an exciting treasure hunt that has brought me more paperweights than actual usable stones, but every now and then I score a good stone at a bargain price.

This nice little rock I found on e-bay. I misspelled the search word and wrote "toisi" instead of "toishi". The search returned 1 hit, and this "toisi" was up for auction. There was one bid in, but I waited for 4 days until 15 seconds before the end of auction and bid $10 over the current bid and I won! A couple of weeks later it arrived in my eager hands and I couldn't wait to try it out. Hoping that the stone would be good but expecting just another paperweight.

Nice and clean stone. A corner missing but good size.
No cracks but a few firm and light inclusions not affecting sharpening negatively.
Observe the small black seeds like vanilla

Kiita with a greenish hue to it. Almost like green tea jelly with vanilla seeds

Clean and homogenous side with a few firm lines

The stone looked very old as it was previously lacquered to reinforce it due to its rater soft composition. The lacquer was yellowish and tarnished of age and the stone looked used. That was a good sign. I started out removing the tarnished lacquer and applied a couple of fresh layers to keep it stable.

The stone board is free of cracks but have some firm inclusions that does not effect sharpening in a negative way. The colour is kiita with a greenish hue with what looks like vanilla seeds in it. Very small black dots spread evenly throughout the stone. Might be renge or goma or something. It seems very uniform and has this velvety cool feeling to the touch.

The skin is very nice and dramatic looking with its very clear palette ranging from dark brown to a rusty orangey color. The stone itself on the bottom side is a light kiita color.
Dramatic and beautiful skin on the stone

Very nice back side with a clean kiita color under the skin

So for the sharpening experience. I pulled out my trusty Kasahara Aoko #2 kasumi usuba from Iida Tools. I use the same knife for all my tests as this gives me a firm reference for comparison and a large area to show the qualities of the stone.

The stone gives up slurry quite easily. The slurry to swarf ratio is fairly modest and the feel was very creamy and non-scratchy. What was immediately apparent, however, was the stones ability to make a high contrast between the jigane and hagane on the knife. It was clearly visible even through the ritch slurry. Even if it is a fairly soft stone it wears pretty slowly and will stay flat for a long time.
Very rich slurry. The light color indicates modest swarf to slurry ratio.
Looking at the result, we can se that the stone is not a final finisher. However, it produces a finish with very shallow scratches which makes it a very good pre-polisher for the final finishers. It also leaves a fairly dramatic contrast between ji and ha which I like a lot.

Nice contrast between jigane and hagane, but not the finest of finishers.

To sum up. The stone was a bargain for the price paid. However, most of the times you get what you pay for and this is not a very agressive nor a very fine grit stone. I believe the quality is fairly good.

The stone is a fairly good performer that sharpen most kitchen knives more than sufficiently for daily use. The edge off the sone compared a lot to the edge off my Oohira Asagi which is rated Lv 4,5 and #6-8000. As it is a fairly soft stone it is also very easy to use and very forgiving when sharpening. I believe it will be a very good stone for the beginner and intermediate sharpener.

If anyone have an idea what stone this might be, please leave a comment. I am excited to hear your opinions.


  1. The stone looks good.
    One remark though, cashew lacquer can be purchased in many color varieties, from transparent to black, so color of the lacquer coat does not indicate age.
    Hope this helps.

  2. Thanks for your input Mainaman. You may very well be right about that. I have seen cashew lacquer in a lot of different colours. My impression is that the cashew lacquer is fairly hard while the coating on this particular stone was rather soft and a bit flexible. More like the waterbased stuff sold by 330mate amongst others. This waterbased lacquer is milky white in the bottle but dries to a fairly thick transparent film with a bit of flexibility. I don't know for sure, but that would be my guess.