Natural Japanese Whetstones Explained

 
     

Whetstone comparison

 
  Hello curious visitor. I have recently became curious about Japanese whetstones, both natural and synthetic. Buying a natural whetstone is always a gamble, and worse off all the naming and classifications are very confusing. Using this page I will try to create a reference guide to naming conventions while learning it myself. Here is a matrix classifying the stones:
 
Naming Convention: Mine Design Strata-group. Example:
Renge means a lotus flower. (Kuro renge - Black Lotus)
Suji means cracks
      Kane-suji.....Toxic. It contains metal or iron particles. Effects sharpening
      Ke-suji........ Safe. We can see it, butr there is no influence. Suita has many of these.
Hari means needles, small cracks...
      Harike.....Toxic
      Atarazunohari....Safe
Kan means rust colored design, mostly non-toxic.
Aiishi no abrasion power
Honishi good abrasion power
 

Hon-kuchi naori (Huge layer of rock suitable for use as sharpening stones)

Not all strata in all mines produce good sharpening stones. Aisa, Tomae, Namito are good in Nakayama, but good Suita layers in Nakayama are all depleted.

East side of Mt. Atago:  Higashi-mono West side of Mt. Atago: Nishi-mono Norh-East of Kyoto:

Queries: Nakayama, Okudo, Oozuku, Narutaki, Shoubu, Kizuyama

Queries: Oohira, Sinden. Queries: Sougandani, Takashima
Groups of strata with similar characteristics from top/shallowest to bottom/deepest (deeper stratum produces harder stones):

Aka-pin
Tenjyou suita x4 (uchigumori, nagagumori, sotogumori, shiro) 
Hachimai x8
Senmai x2
Tomae x48
Aisa x4 (Karasu is sometimes found in this strata)
Namito x8
Hon suita x6
Shiro suita x2

Groups of strata with similar characteristics from top/shallowest to bottom/deepest (deeper stratum produces harder stones):

Aka-pin
Tenjyou suita x4 (uchigumori, nagagumori, sotogumori, shiro)
Hachimai x8
Senmai x2
Tomae x48
Aisa x4 (Karasu is sometimes found in this strata)
Namito x8
Hon suita x6
Shiro suita x2

Groups of strata with similar characteristics from top/shallowest to bottom/deepest (deeper stratum produces harder stones):

Aka-pin
Tenjyou suita x4 (uchigumori, nagagumori, sotogumori, shiro) 
Hachimai x8
Senmai x2
Tomae x48
Aisa x4 (Karasu is sometimes found in this strata)
Namito x8
Hon suita x6
Shiro suita x2