Ryujin – Natural Whetstone from a Historic Tunnel Quarry
In the mountains of Ehime, several old tunnel mines—known as shiki (鋪)—still remain from centuries past. The stones extracted from these tunnels differ subtly from those mined through open-pit methods.
Among them is a rare and enigmatic type known as Ryujin, named for its mysterious, almost indescribable appearance.
Most of these tunnels have collapsed over time and are now sealed off, their entrances lost to erosion and decay. Yet from these perilous places—once described as “minoke mo yodateru” (“enough to make your hair stand on end”)—one can sense the passion of those who risked their lives for whetstone craftsmanship, and the 1,300-year legacy of Iyo-to.
As a whetstone, Ryujin is extremely hard and features a very fine grain structure. It functions best as a mid-finishing stone and works well when used with a diamond plate or Nagura for slurry generation.
The tactile feel and final finish change significantly depending on whether you begin with mud release or not.
