Tsushima Black Nagura

Tsushima Nagura

Tsushima Black Tomo Nagura

These black Nagura were quarried some time ago at a now closed underwater mine on Tsushima Island off the coast of Nagasaki. Traditional woodworkers in western countries referred to this stone as ‘Ocean Blue’, and they used these stones for finishing the polishing stage on chisels and other fine cutters. Allegedly, there is another type of Tsushima Black that was quarried inland at another source.  I am not certain whether or not that the other type, referred to as ‘Mountain Tsushima’ is the same type of stone. I have read and been told that it is not as fine or consistent as the ‘Ocean’ type.  

These particular Nagura are in fact of the ‘Ocean’ variety. They’re quite hard and the slurry they produce starts off being fine, but it seems to break down considerably. Finishing a straight razor on Tsushima Black slurry can be compared to finishing on Mejiro or Koma and possibly some Tomo Nagura also.

The sides of each of these Nagura are sealed with cashew lacquer, which is a traditional protective treatment. I am unable to tell if there is a layer of rice paper under the lacquer but I suspect that might be the case.  

I’ve used these with great success mixed into a full Mikawa Nagura progression, or as an option for touching up a slightly dull edge. They are also ideal for raising a slurry on a full-size Tsushima Black bench-stone Tennen Toishi. 

Like most Nagura, they can be used on natural stones, as well as synthetics. 

Thre’s a not-so-short clip showing Tsushima Black Nagura being used with a Naniwa ‘Snow White’ here

Approx. Dimensions

Large: 1.8 x 1.8 x 1.8” / 45 x 45 x 45 mm

Small:  1.4 x 1.4 x 1.4” / 35 x 35 x 35 mm 


Large: 10.1 oz / 285 g

Small: 4.3 oz / 122 g

© Keith V Johnson 2014 - 2018