206 - 80 - 58mm
2.55 kg = 5.6 lbs.
Reads on the stone top from the upper right down in small kanji GOKUJO (extremely fine
And in larger kanji to the left HON-SUITA (the name of the strata)
The middle left edge reads BIWA after Biwa lake near Kyoto.
At the lower right corner SAIKOKYU (very best quality)
A giant 5+ pound awase toishi of superior quality and purity, stones of this quality and
character and size have not been mined for many years and come from the deepest
strata of the mines of Kyoto. These mines were known to be dangerous to the diggers
because of typical mine hazards and the stone processors and the miners because of the
extremely fine dust particles that caused lung disease. Most of the mines closed before
The back of the stone is very flat with some chisel marks and lots and lots of renge
showing there too. None of the lines you see in the stone are structural and do not affect
the sharpening qualities in any way as they are softer than the steel.
This is a very, very fine grit stone that produces a bright chrome like finish to the hagane
that you can see in the photos while leaving the jigane soft and reflective. I used a
diamond plate in the central lower area to test the stone and break through the oxidized
skin that has formed over the last 50-60 years. I found the stone to be very easy to use
after the diamond. Before using the plate I could sharpen and build a paste but it took
longer to do so
This Shiro (white) Hon-Suita stone came from a store in a small town in Japan that closed
in the 1970s containing stock dating back to the 1930s. This awasedo has not been used
other then to test the quality at one edge of the stone as you can see in the photos, and it
is considered to be NEW/OLD STOCK.
The stone as it sits looks a bit tinted buff because of the decades old microns thin skin
that is the result of exposure to the air. This will come off with the first sharpening or use
of a diamond plate giving the stone a much lighter tone and looking more like the white of
the back. The renge is thick and purple and runs all around the stone and you can see it
on the sides of the stone too. This awase toishi when top dressed using a diamond plate
produces a very white paste. Using this paste to sharpen a blade produces a thick black
slurry very quickly. I am recommending that all of these deep strata hard stones be top
dressed with a diamond plate and I feel that the use of a diamond flattening plate is the
key to using these hard stones. I use an medium grit Atoma myself. When I do develop a
paste I try to leave it on the stone after using and not wash it off to save it for the next
time I use the stone.
This stone has tremendous cutting speed/strength and produces black water within a few
Note: If you have never had an opportunity to use a true hon suita awase toishi before,
don't miss this stone. They are very rare and in the U.S. almost non existent on the open
market in Japan, especially in this large size.