Thread: Tsushima "Ocean Blue" 12K

Originally Posted by Aerdvaark

Is it a cnat? I say that because the cnats are advertised as 12k.

I have a CNAT. Although the density of the "ocean blue" stone is similar to the CNAT, the color is quite different. Thus, I do not think the "ocean blue" is a Guangxi stone. However, good ones can both be finishers.

The two Tsushima stones with which people are most familiar are the Tsushima ocean black and the Tsushima mountain stone. Everything I have read about these two stones says that they are mid-range stones, not finishers. The "ocean blue" may have come from a different strata in the same mine from which the "ocean black" came. Thus, it has different characteristics.

I do not have a known JNAT with which to compare the "ocean blue" stone. Even if I had one, I would not expect the "ocean blue" to have similar characteristics.

It is my understanding that many of the traditional JNAT stones come from the Nakayama region. That is in a region of Japan that is about 100 miles from the ocean. Tsushima is an island about 1500 miles southeast of Nakayama. The stones are supposedly quarried from an underwater mine. Why would anyone expect a Tsushuma stone to have the same characteristics as a Nakayama stone quarried 1500 miles away. Each stone has to stand on its own merits.

The Coticules of Belgium and the Eschers of Thuringian, Germany come from mines that are only 500-600 miles apart, yet the stones are very different. Just because they are different does not mean that both do not have usefulness as razor hones.

Originally Posted by Aerdvaark

Is it a cnat? I say that because the cnats are advertised as 12k.

Doesn't look it from the photos of this stone I've seen. At least if we're talking Guangxi hones. This Ocean Blue seems to be a deeper blue color, as opposed to the Guangxi's light grey. And I haven't seen the same black banding, or copper colored inclusions that are common on Guangxi stones.

Thread needs more pictures from Ocean Blue owners!

Did a quick hone tonight, test shave will have to wait until tomorrow. Here are a couple quick scope shots, first is a Jnat Asagi, second is the Ocean Blue. I took the Ocean Blue to 8k synth first, then to a light tomo slurry and after 40 laps or so, lightly diluted that until it was quite watery but slurry was still visible and did another 10 laps. HHT is good, HHT4 I'd say. I will be doing quite a bit more playing with progression on this stone.





As you can see it leaves a completely different scratch signature compared to a regular JNat. Every JNat (finishing grade - not something like an Aoto or Amakusa) I've ever tested leaves a pattern similar to the one shown in the first pic here. I'm not yet certain whether it actually did much to the 8k edge - before the TOB hone the razor looked very similar to after except without the anomalous deeper scratches.

BTW, don't concentrate on the cutting edge/apex appearance too much in these pics - the lighting here is optimized to show scratch depth, so shadows falling on or near the apex can partially obscure portions of the apex in these photos. I use a totally different method for looking at the apex (dark field with only the thin line of the apex lit/reflecting).

Here's a picture of my Ocean Blue and Cnat.

Here are a few clear shots of my TOB. All indications are that it is a natural stone - notice the inclusion at one end that wraps around the side - and layering is also visible.

It seems odd to me that there would be a strong enough market for 'sharpening stones' to do underwater mining on an island. I suppose that it's true, just sounds odd.

Originally Posted by kelbro

It seems odd to me that there would be a strong enough market for 'sharpening stones' to do underwater mining on an island. I suppose that it's true, just sounds odd.

I suspect war demand for abrasives did play a role. Some of the Kyoto mines were mined until they were underwater with draining machines, I saw a photo from that, I think it was Alex who uploaded it but I might be wrong. Anyway, these damned wars are a reason we pay several hundreds of $$ for a real Jnat and are now talking about some strange Tsushima stone. If it wasn't for them, a lot of the good Kyoto mines would still operate.
As for this specific stone, there is a slight chance, aside from the chance that the deeper layers were compressed until hard enough to be fine enough, for a vein of the stone to continue at some other place that wasn't known as well for the below reason, and is now resurfaced. There is also the chance that the seller found a place with the stones that were considered "second grade", maybe from the original quarries, maybe from some other location (if you have access to real Kyoto stone, any other stone with potential as a finisher would be considered not worthy to even mention its existence) and are now sold as "the fine ones", since when you are buying or were buying in older times, Tsushima stone, you are looking for the mid range stone with some speed, not some fine BUT slow one. It's entirely possible for these extra hard, as well as too soft ones to exist but were not held in high regard, with the classic Tsushima mid stone being the one extracted in the biggest quantity, and having the highest demand for these specific characteristics.

Good point Vasilis. Kind of like the BBW stone that surrounds Coticule. 'Junk' stone that was only used as backing for a coticule for the longest time. Maybe they've just now found a market for it, and are unloading it on the cheap. Which could be to our benefit as straight razor users.

It may not impart the same edge as an Asagi, but if it's on par with a good Cnat - with more uniform results and less a roll of the dice - then we have a good reasonably priced entry level stone for new guys to get hold of.

Originally Posted by eKretz

Here are a few clear shots of my TOB. All indications are that it is a natural stone - notice the inclusion at one end that wraps around the side - and layering is also visible.

This looks exactly like my cnat...

Seeing the link for a second time, I don't recognize any of the kanji, and, searching for radicals for some time now, I can't find them in Japanese or Chinese.
Are there any Japanese speakers around here to translate that golden stamp of authenticity? One more but tiny detail; is it just me, or the stamps in most cases are read from up to down and not sideways?
Is it some Tsusimese language? In any case, it doesn't say Tsushima, blue, ocean or hone.
I know, a good stone is a good stone anyway, still, anyone has any idea of what's going on? Is the address of the seller at least in Japan?