Ohira Kiita with black nashiji is my guess !
Usually unknown stones is from Ohira mine, many of them did not have any stamp and that mine is still active. Skin looks like from that mine too very brownish.
You got your self very good stone I love these soft stones for knifes some call them "Uchigomori" like the strata in Tenjyou these stones do not sharpen much but get contrast out of the steel.
Thanks Max. Your input is highly appreciated. What you describe sounds a lot like the stone in question. Perhaps it will also do a good job with bringing out contrast in damascus.....
Originally Posted by maxim
Other opinions or guesses are welcome I know there is a lot of knowledge out there. Bring it on!