Highest grade (Maruhatsu). Mined ~1940's by Michiaki Tanaka.
Brand: Tanaka Toishi 田中砥石工業所Producing Area: Kyoto - Japan
Mine: Unknown. Kouzaki?
Appearance: Blue, like its name.
Size: 240 x 67 x 77mm
Grit Range: 3000-6000
1-5 Scale: 1 = Less, 5 = More
Hardness Level: 4
Scratch Depth: 3
Self Slurry: 2
Ease of Use: 3
Recommended Uses: Polishing...
Notes: This is the real deal. Mined all the way back in the 1940s by the then president of the famous Tanaka Toishi company. This will be harder and finer than the Aoto that are more common today, which are usually from the Tamba region. Since it's harder and finer, the scratches are less deep, and it will provide a glossier Kasumi than today's Aoto. Since it is harder, it is a little more difficult to use and slightly slower. You could use this on some razors and tools.
Disclaimer: Given the natural aspect of these stones, all subjective qualities are our estimates and may vary slightly from your exact expectations and assessment. The images shown and characteristics described are an example. If purchased, yours may differ slightly in appearance and qualities. Dimensions, weight, and stamps may be different from listed if it has been tested.