Here is a new blacksmith we are speaking to
There are, still now, more blacksmiths in countryside in Japan making black finished knives called Kuro-uchi in Japanese by forging.
The name is Ueda Cutlery Manufacturer ( Ueda Hamono Seisakusho in Japanese ), located in Kuma-Gun ( near Hitoyoshi-City ), Kumamoto, Kyushu. I am not sure how far but about 1 hour drive to south east from Moritaka in Yatsushiro, Kumamoto.
They have more than 120 year history and are working 3rd, 4th and 5th generations together according to their introduction.