I was curious about this, too. So, I shot Naniwa an email. Their response is what follows.ex1580 wrote: ↑Wed Aug 24, 2022 8:49 am Does anyone know how many microns the Naniwa Super Stone 12,000 and Arashiyama 6K are? I didn't see them on the chart. I have looked all over the internet and I am guessing about 1.2 and 2. I am trying to keep track of various things I have sharpened to learn more but the various grit standards are confusing so I am trying to convert them to microns as best I can to see if that helps. Thanks!
https://www.chefknivestogo.com/na12grsu.html
https://www.chefknivestogo.com/takenoko8000.html
Thank you for the inquiry.
The size in micron of the S2-491 is 1~2μm.
Best Regards,
Naniwa Abrasive Mfg. Co., Ltd.
After spending about 20 minutes looking for a manufacturers website for the Arashiyama, I threw in the towel on that one.... for now... most likely until laundry day at least.