Thread: Tsushima "Ocean Blue" 12K

I recently purchased a Tsushima "ocean blue" Japanese 12K natural sharpening stone. There is also a Tsushima "ocean black" stone, but I think it is lower grit stone more suitable for mid-range honing after setting the bevel. The "ocean blue" is a finisher.

Do any of the other SRP members tried using this stone for razors? If so, please relate your experience with this stone.

Supposedly it comes from a recently closed underwater mine in South Tsushima Island. Because the stone was mined until recently and is more available than some of the JNATs that came from mines closed decades ago, the price was reasonable, but is not a cheap stone.

The stones are available in a variety of sizes; I purchased a 8.0" x 2.7" x 1.0" stone that is an ideal size for razor honing. It comes with a matching Nagura in a leatherete case.

https://www.amazon.com/Natural-Sharp.../dp/B01CMY2HA2

I was only able to find a couple of reviews of Tsushima stones on YouTube, both by Robert Ortiz. I think one is on the ocean blue and one is on the lower grit ocean black.

The stone seems to be exceptionally uniform in structure, no inclusions, cracks, layering, etc. It was lapped on all sides. Although it is impossible to assign a true grit rating to a natural stone: by feel, under a 30x magnifier and by honing scratch pattern, I have no doubt that the stone I received is 12K or higher. I have both a C12K and Naniwa 12K SS for comparison. Some of the reviewers of the stone loved it and others thought it was a lower grit stone, but the one I received seemed to be 12K.

I used the new stone to refresh a couple of razors that weren't quite giving as good a shave as I wanted and found that it did improve the edge, both under the microscope and on my face. I created a slurry using the Nagura, started with circles and finished with water and X-strokes. As the edge gets polished. the stone get quite sticky.

I will have to do a lot more experimenting before I can tell you whether the Naniwa 12K, C12K, or Tsushima "Ocean Blue" 12K give the best edge on the majority of my razors, but for now, I am pleased with this addition to my tool kit.