The Hoard Story
The Nakayama, Okudo, Narutaki, Shinden, and other Honyama mined stones of the Hoard came from a neglected and nearly forgotten Air Raid Shelter that was tucked under the floorboards of an old fashion hardware store. Over a period of a few years the owner has released a limited number of stones at a time to me from his store nestled in a small rural town in Japan.
With my first opportunity to buy any of these stones, I had to be selective because the owner had placed "collectible" prices on them which was much higher than I would had been paying from the commerical stone sellers. Everytime I went back to the Hoard it seemed that the prices crept a bit higher. It turned out that each and every stone was hand hewn, the sides were hand sawn and hand scraped and many of the stones had rich kawa (rough mineral skin) on 3 or 4 sides or the back. This was unique enough to justify the prices. He indicated that they were dated as early as the late Edo Period and certainly many if not all were mined before or during the Meiji period. A fact that he had picked up on from a friend.
Some of the smaller stones I could tell were harvested from narrow nooks and cavities within the mine complex. The larger rectangular stones prepared for sharpening knives and tools were large to extra large with the giant of them all, an asagi being 245 x 104 x 58mm thick that weighed 3627grams, equal to about pounds. Many of the stones are over 50mm thick and a few are 60mm. These are professional size or multi-generational size stones that will last years and years in a busy shop.
The seller, who was 71 years old when I first met him, told me that his grandfather bought the stones at least 90 years ago and that because the family never had been a stone or tool store, they never sold enough to bother with displaying them them over the last 60 years.
The use of hand saws (kibiki) to cut and shape tennen toishi sharpening stones from the Kyoto mines dates back to the 1100-AD and ceased in the late 1800, so by the 1920's most if not all of the mines began to use circular power saws. Historic wood block prints from the Kamakura period illustrate crews shaping the stones with hatchet work on the bottom side, while 2 man teams are sawing the sides with kibiki.
As a group, but really from stone to stone, this collection is made up of the fastest cutting stones I have ever owned or tested. The fastest of them will remove and replace King 1k or Shapton 2k scratches within 15 strokes or fewer if a slurry is made from the base using a #1200 diamond plate. Without slurry and just clear water these stone will finish up a Henckels razor to the keenest states with a bright finish with little effort.
I have found that each stone is so similar in hardness (slightly softer than modern minend stones), and cutting speed and fineness, as a group they clearly do represent an era.
The first four photos below show the interior of the shelter which is about 5 x 6 x and 5ft high. The last photo shows a selection of stones in my shop ready for lapping and polishing. I made it my goal to buy all of the stones, but towards the end they becamer too expensive.