My information all comes from professionals in the field, and most particularly from the book "The Charm of Kyoto's Natural Hones", published by the Kyoto Natural Hone association. This group, founded nearly 30 years ago, is an association of miners, wholesalers and researchers dedicated to the promotion and preservation of these natural hones as pieces of Japanese culture and history. These are the men who grade the stones, stamp them with the particular names and qualifications we will see below, and have the years of experience and education that I myself lack.
A
Aisa (also called Gousa)-合さ-Direct translation "Meet"(???). A seam in the Honkuchi Naori, in the very middle of the strata. Produces very hard stones. Karasu stones are a very thin seam in the Aisa.
Aishi Naori-合石成り-Direct Translation "Meeting Stone Strata". A line of hone stone strata that extends from Yuuge, in the North of Kyoto prefecture, southwest to Tomita. Produces stones that are softer than the Honkuchi Naori, and somewhat coarser, but relatively big and clean. The Hideriyama stones are especially famous.
Asagi-浅黄-Very confusingly, the direct translation is "Light Yellow". Color Variant. According to "The Charm of Kyoto's Natural Hones", Asagi hones are light blue or dark grey, and are usually very pure and hard.
B
C
Coppa/Koppa-小端-Direct translation "Small part". An irregularly shaped stone, usually smaller in size than the regular benchstones. Often cheaply priced due to their unusual shape.
E
Enshou-煙硝-Direct translation, "Gunpowder". A stone with a heavy sulfur content, causing a blueish or blackish color, and on use it can produce some discoloration in steel, and releases a gunpowder smell.
H
Higashimono-東物-Direct translation, "Eastern Thing". The mines located to the East of Atago Mountain in Kyoto produce stones from the Honkuchi Naori that are known as "Eastern Things." They are known as the hardest, finest and best of all the hones produced in Japan. Mines include Nakayama, Narutaki Mukaida, Ozaki, Oozuku, Shoubudani and more.
Honkuchi Naori-本口成り-Direct Translation, "Main Opening Strata". The Honkuchi noari is a line of rock strata that runs for about 20km, from the Narutaki district of Kyoto northwest to Oouchi. The Honkuchi Naori is the source of the hardest, finest hones in Japan. Seams include Tomae (most numerous, synonymous with "Awasedo"), Aisa/Gousa, Suita, and many more (80 seams in total).
K
Karasu-カラス・烏-direct translation, "Crow/Raven". Color variant. Light colored stones with black, feathery spots (the black spots are the "raven" part--no spots, no karasu). They come from the Aisa (sometimes called gousa) seam, and tend to be very hard, smooth stones. Stones from this seam are often recommended for fine honing, as for razors.
M
Maruoyama-丸尾山- Direct translation "Circle Ridge Mountain" or "Circle Tail Moutain". A "Western Thing" mine northwest of Kyoto, located in the Oouchi district at the intersection of the Honkuchi Naori and the Aishi Naori. Produces stones from three locations-Ashitani, which is in the Aishi Naori, and Ipponmatsu and Gobyo, which both are in the Honkuchi Naori.
Mejiro Nagura-目白名倉-Direct Translation "White-eye". A middle-range nagura, between Botan and Koma.
Momiji-もみじ・紅葉-Direct Translation, "Maple, Maple Leaf". Figuration/color variant. The book "The Charm of Kyoto's Natural Hones" lists Momiji as a color/ marking pattern particular to the Suita, making it especially desirable. According to Youzo Tsuchihashi san, 4th generation owner of the Maruoyama hone distributors (Totoriya) and miner, Momiji is the same color variant as Renge (reddish spots) but the spots are considerably bigger than the very fine renge. According to Yasuyuki Bo-oku san, a 3rd generation Kyoto hone wholesaler and distributor, and member of the Kyoto Natural Hone Association, these patterns are prized for their aesthetic qualities, rather than any effect on honing. N
Nagura-名倉-Direct translation, "Famous Warehouse" (not related to anything specific). The best nagura are sourced from a mountain near Mikawa town, in northern Aichi prefecture, Japan. These stones are small, soft chalky stones used to create a succession of slurry "pastes" (In Japan called "Tojiro", hone juice, or "Todoro", hone mud.). Come in a total of 12 varieties, but only 4 concern razor honing. See also "Koma," "Botan," "Tenjou" and "Mejiro."
Nishimono -西物-Direct Translation "Western Things". The mines arrayed to the west of Atago Mountain, northwest of Kyoto, produce stones called "Western Things." They are not quite as hard, on average, as the Higashimono, but still very fine and of excellent quality. Mines include Oohira, Maruoyama, and many more.
R
Renge-蓮華-direct translation, "Lotus Blossom." Figuration/color variant. The book "The Charm of Kyoto's Natural Hones" lists Renge as a color/ marking pattern particular to the Suita, making it especially desirable. Renge are Shiro-suita (white suita) with a fine, distinct reddish/pink, sometimes brown or black, pattern. According to Yasuyuki Bo-oku san, a 3rd generation Kyoto hone wholesaler and distributor, and member of the Kyoto Natural Hone Association, these patterns are prized for their aesthetic qualities, rather than any effect on honing.S
Shoubudani-菖蒲谷-Direct translation, "Iris Valley". The name of the area between Mt. Atago and Kyoto City proper, which also lends its name to one of the "Higashimono" mines, producing top quality finishing hones.
Su-巣-Direct Translation, "Net, (spider's) web". Su are small holes, ranging from about 1mm to sizes invisible to the naked eye. They are the remnants of gas bubbles trapped in the stone at its formation. They are especially common in the Suita seam (hence the name). They can hold slurry and rough particles in honing, and so caution should be used when honing very fine edge tools.
Suita-巣板-Direct Translation, "Webbed plate". One seam of the Hon-Kuchi Naori, the layers of rock that produce Kyoto's natural hones. Very popular, and known to be fast, fine hones. Often have su.
Sunashi-巣なし-Direct Translation, "No Web". A suita stone with none of the eponymous su.
T
Tenjou Nagura-天上名倉- Direct translation "Heaven, Sky". Finer than the Mejiro, but still a midrange nagura.
Tomae-戸前-Direct Translation, "In front of the door". The most common of the Honkuchi Naori layers (48 of the total 80 are Tomae), and produces a large number of stones. In "The Charm of Kyoto's Natural Hones", there is a section of "Q&A" (it isn't exactly clear who is doing the asking and answering, but anyway...). In the Q&A, it goes "Q: Why are "Tomae" such good "Awasedo"? A: 1) They represent the essence/heart of natural hones. 2) "Tomae" comes from "In front of the storehouse door". 3) Rice was kept in the storehouse. 4) So if a miner reached these stones, he could keep producing them [because the seam is so large] and so he would be able to eat."
Tomonagura-共名倉-Direct translation "Paired Nagura". Also known as a "Shougata Honzan" 小型本山, meaning "small-form true source mountain". This is a slurry stone, but is NOT one of the white mikawa nagura stones. These are small pieces of a fine finishing stone, a Honyama/Honzan stone, used to raise a fine, pure slurry for finishing purposes. Vital for the traditional Japanese honing method described by Kousuke Iwasaki, and taught to me by my barber.
Y
Yake-焼け-Literal Translation "Burn, brown". Color variation. Dark golden brown streaks, like the stone has been roasted.
