#85##85 Nakayama Karasu tomae
KARASU tennen toishi are rare in and of themselves, and are exceedingly scarce with the
solid bold pattering found on this example. The living edge sides flare out to create a
solid base that is 230mm long, 90mm wide at one end and tapers to 60mm wide at the
other, The top surface is a generous 230mm long by 75mm and tapers to 40mm wide.
This is a hard stone with the finest imaginable grit occurring from a naturally mined
stone. This karasu can be used with a tomo or Mikawa nagura, a diamond nagura*, or
with just clear water as a final honing stone for plane blades, chisels or as are popular in
Japan as a barber's razor hone at which it exels.
A fugitive type stone, Karasu is found in the Aisa strata which is a deeply compressed
layer in the mines around Mt. Atago. Karasu is believed to be a name ascribed by the
early miners to these black pattern stones as representing "flying crows" against a gray
sky. The minerals comprised in Karasu are, along with the dominate silica is a
concentration of mica which gives the black contrasts. True Karasu toishi have these
small pinpoint specks of mica which as groups create these bold, blotchy or wispy
deposits with graphic imagery.
* Diamond Nagura is the use of a diamond plate to raise a slurry composed of the host
stones own grit particles.