By Nathan Lee - KIRU sharpening 16.12.2021
The Aizu is one of my personal favourite Japanese natural stone. The mine is located in Northern Japan, not your Kyoto Jnats. I've owned 3 whetstones from this mine and they are all good quality stones.
Aizu stones have a very uniformed grit, comes in a big size, is good for sharpening kitchen knives, and give kitchen knives a toothy aggressive edge. Polishing wise, it gives a natural kasumi finish that you would expect from a mid-coarse grit Jnat. Personally I think it's at the sweet spot for my double bevel knives - just at a sweet spot to see the contrast between Jigane and Hagane.
The three I've tried all fall into the "mid coarse" grit category and interestingly with some Nagura surface maintenance, they can produce noticeably finer finishes.
The one I purchased recently, is the biggest one I've tried. When it first arrived, it was 2,957g (almost 3kg!!). I didn't like the shape as one corner was too beefy, so I shaved it down a bit. Now it's a consistent ~80mm in width and down to 2,657g.
Maybe due to the size of the stone, it absorbs a lot of water. I found it easier to use after I placed it under running water for 2-3 minutes - I'm not very comfortable with soaking it yet!
Stone pics
Close up details and slurry pics
Finish pics
Sharpening video
Feedback
I enjoy this particular stone a lot! Sharpening feedback without any slurry on the Aogami super is gummy, a bit chalky, and tells you if you are following the old scratch patterns or creating new ones.
With nagura slurry the feedback is very smooth, still chalky enough so that you know you're removing material.
With diamond slurry, it gives the chalkiest feedback out of all 3 surfaces. I could tell it's removing the most material under similar time frame.
For edge, it gives enough bite and refinement on the edge of my knife. It feels similar to the Morihei 4000, maybe slightly toothier.
Characteristic of this stone (on a scale of 5)
Hardness - 4
Fineness - 3 with atoma slurry, 3.5 with nagura
Speed - 3.5 (5 refreshed)
Tags: Aizu, Japanese natural stones, knife sharpening, knife sharpener