Mikawa Shiro Nagura 1lb 4.5oz. (580g) Japanese Natural Sharpening Ston
Mikawa Shiro Nagura 1lb 4.5oz. (580g) Japanese Natural Sharpening Ston
Mikawa Shiro Nagura 1lb 4.5oz. (580g) Japanese Natural Sharpening Ston
Mikawa Shiro Nagura 1lb 4.5oz. (580g) Japanese Natural Sharpening Ston

Mikawa Shiro Nagura 1lb 4.5oz. (580g) Japanese Natural Sharpening Ston

Regular price $220.00 Sale price $205.00 Save $15.00
/

Mikawa Shiro Nagura 1lb 4.5oz. (580g) Japanese Natural Sharpening Stone

Approximately 117mmx75-80mmx27-33mm

I am not sure which layer of Mikawa shiro nagura is, but it looks fine grit.

Hardness-------------8.8

It raises good amount of black color slurry quickly.

(Scale; 1 to 10, 1-3 is very soft muddy rough grit whetstone 3-6 is soft medium grit whetstone, 6-8 is hard medium grit whetstone; 8-10 is fine grit whetstone)

Particle Size----------8.8

It makes my blue II steel kasumi blade knife Hagane became semi-mirror finish to mirror finish. Jigae became little frosted silver color finish.

(Scale; 1 to 10, 1-3 give deep scratch marks to the steel, 3-5 is delete the 1-3 scratches, 5-8 makes the steel cloudy, 8-10 makes the steel semi-mirror finish or mirror finish)

According to Dr. Kuniichi Tawara who is a Metallurgy doctor, and very famous Japanese sword researcher, Koma molecule is 10 to 20 micron. It might be like Botan or Atsu (Chu-nagura) class grit. It should be good for one or two stones before starting the fine grit sharpening.

For razor sharpening, it is used one or two before the process sharpening by fine grit whetstone like Nakayama, Ozuku, Wakasa, etc.