Reads on the stone top from the upper right down in small kanji GOKUJO (extremely
fine quality).
And in larger kanji to the left HON-SUITA (the name of the strata).
And in the middle left edge reads BIWA after Biwa lake near Kyoto.
At the lower right corner SAIKOKYU (very best quality).

This Hon-Suita stone with NASHI-JI (skin of the pear dot pattern) came from a store in a
small town in Japan that closed in the 1970s containing stock dating back to the 1930s.
The awasedo has not been used other than 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.

A thick and wide and over 5 pounds, awasedo stones of this quality and character and
size have not been mined for many years and come from the deepest strata of the Mt.
Higashi mines of Kyoto. This stone 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 is a very fine grit stone that produces a mirror like finish to the hagane that you
can see in the photos while leaving the jigane soft but 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.

NOTE:The inclusion lines (mineral deposits other than the base material) in the stone
do not affect the sharpening qualities in a negative way and are usually softer than the
stone, but I did pick out some loose stone particles in the two central areas where the
lines converge (see close up photo) and meet. These loose particles will scratch the
blade if the particles of grit are greater then the general stone grit size. These particles
can be easily removed with a little sharp instrument as I did. Some stones have more
lines then others but you never really know where they will appear. The areas where I
picked may need to be picked again and in time these areas will be worn off by using
the sharpening stone.