To begin with since the World War 2 a lot of the strictly defined relationships between maker/wholesaler/retailer have become fuzzy.
It used to be before 1950 or so, that each had his own niche and that was where you remained just as your father did in the trades.
The miners were at the low end, the retailers at the upper and the wholesalers made their profit in volume. Each party graded the stones as they went along, the miners in piles, the wholesalers in stacks and the retailer on clean work tables. The miners knew their stone from their own mine but did not really know anything about sharpening with them (these are very crude generalizations) and the retailers knew what the general craft community needed in order to perform their amazing tasks. There were no Home Depot stores then and the average household did not have or have a need for razor hones or finishing stones, so over 90% of the stones from the mines went to craftspeople.
In the mine the miners could tell which strata they were digging in, not with shovels but with crowbars, each stone was trimmed with a geologists hammer and any waste was tapped off. Waste was not carried down the mountain for processing but instead just dumped down the hillside. The Ohira Mines owner Ishihara-san told me in his grandfathers day the family had about 20 workers, 3 or 4 at the top of the hill, same at the bottom, so the remaining 15 or so mostly local village women and children hand carried in backpacks all of the stone down to a wagon at the bottom, I can attest that at least an hour hike back up. None of the mines had roads because the mountains were too steep. Some mines developed sleds on skids and now cables.
The miners graded stone on site looking for razor/kamisori stone/toishi because that was the most valuable, and separated uchigumori, tomae-asagi, suita of various strata. Lots of hand work including hand chipping the backs, cutting by hand in the old days or sawing in the shop. Hard, dirty, dangerous and degrading work. No miner every became rich, most lived nearby the trail up to the mine and were rice farmers on the side. This was a traditional craft, lots of pride in doing a good job but no real glory. I was told by Yamamoto-san, a retired mine owner that “out of an honest ton of raw stone found in the thick & rich veins of the mines at their peak, only 10% was useable for sharpening; with 99.9% of that ten percent dedicated for tools like chisels and hand planes; and only 1% of that ten percent suitable for razors.
The wholesalers would come up into these valleys (oh, I forgot the poisonous shakes, snow and bears) and buy stone in bulk whether it was slabbed up or raw by weight or eyeballed. All of the stone was just pennies on the dollar. It was trucked to Kameoka, Kyoto or Osaka for finishing and stamping and distribution. The wholesalers had sales staff that had routes and job sites that they serviced, some guys had a route that included a whole region, some just a major city and they serviced their clients as accounts and revisited their clients twice a year or more. All the wholesale profits as I said were made in volume and I am sure up to this point everyone had back troubles. Most stone was moved around the country by train. Horses were used for some local drayage until the 1950s.
Small and large mom & pop hardware stores were everywhere pre-1950s and they sold mostly dry goods and stones for kitchen knives, the tool shops were also plentiful because Japan was a nation of arts & crafts to the extreme and in towns and cities men were constructing the largest wooden buildings in the world and every single house using hand cut and sawn jointery and no nails. The carpentry trades were the largest users of sharpening stones and the demand was high because a carpenter could wear out a stone in a season or two. There were barbers on every corner and every 10 years or they needed a new set of stones. The retailer usually allowed the wholesale sales person to price the stones for the shop even using the wholesales stickers. Shop keepers knew what type of stones he could sell but again new very little about using them or the difficulty of mining them.
Almost all of the major mines closed before the 1st World War, and those that didn’t were depleted from the over burden of WW2’s demand for abrasives. In the 1950s everything began to change: hardly any miners or mines, the use of power tools and stick framing hit the wholesale business and eventually the urbanization of Japan hit the small stores more and more as the decades advanced.
Because I buy wholesale in Japan I need to follow some of the same guidelines that they do in Japan in grading stones. I do mark them up to allow for some profit but I am working off a set purchase price myself. Because of my inexperience I do make mistakes and have to take a loss sometimes.
With all things being equal I work in as logical way as I can. I feel that cutting speed is King, fineness is Queen, and stone size is the Prince. So in a process of elimination I use these factors, pretty much the same ideas posted by the members here already:
Large top deck trumps small top surface
No cracks trumps some cracks
All whole & square corners trumps chipped corners
Fineness trumps coarse
Cutting speed trumps slow cutting speed
Thickness trumps thin
Nakayama trumps all other mines
Color stones trump bland stones
Those are the basics.
Eastern mines almost always trump Western mines
Older stock or even used stones can trump the obvious newly made up stones
Highly figured granular patterns generally trump plain monolithic patterns and colors
Kiita trumps most everything
Renge trumps plain
Nashiji trumps plain
Most anything trumps light gray
Old stamps for me trump new fresh ink stamps
That’s the gist of it.
There are aesthetics involved, everyone chooses an appealing entity, and I would rather not follow trends. I am not an actual collector so a really pretty stone also has to have good sharpening abilities. I know that this was sort of long, if you feel fatigued, I suggest you stay away from my blog.