There are two variations of jinoko:
Kyoto jinoko, red-brown in color (or yamashita).
Wajima jinoko, dark gray in color, made from cooking diatomaceous earth, an earth rich in residues of fossilized plankton and algae.
In Wajima, jinoko is classified into four grades according to its grain size: ippenji 1, nihenji 2, sanbenji 3, and the one I am offering you, yonhenji 4 (the finest). I use it to perfect the fillings, thus ensuring a smooth surface as a final coat before applying the lacquers.