This very interesting stone was taken from Tomae strata in the area where the famous Aoto were quarried. These rare stones are harder and finer than Aoto; they are hard enough to hone a straight razor but perhaps not hard enough to get a superlative finish.
I put these at the top end of the mid-range, alongside Tsushima Black Nagura. They differ from TSB in feel, speed and they are, perhaps, a bit finer too.
