Narutaki akapin kiita. This graphic form of black karasu is a manganese intrusion that occurs at the later stage of sedimentation. It does not affect the utility of the stone one way or the other. The hardness is 3- on the Mohs scale. There is one tight shallow inclusion on the back that hosts at an intersection a harder Al2o3 component. This can be managed so as to not affect the use of the stone.
The sides and ends of this stone were hand-sawn at the mine over a hundred years ago and are now sealed with spar varnish.
A true razor-grade stone with super fine grit, it will hone a host of steel types. A generous tested tomonagura slurry stone will be included.
190 x 67 x 25mm thick
$950