Thread: I declare this: Ozuku madness!

After enjoying the Shoubi-Doobi thread which in the end lead to me buying a Shoubudani Asagi from Maksim,
I wanted to start a similar discussion about the Ozuku.

Now we all know there has been a time where a stone from the Nakayama quarry has been considered the japanese Natural for finishing a straight razor. Nakayama produced great stones and the very best of them (most if not all with either Maruka or Maruichi, or both and sometimes with the Nihon Kamisori stamp) have been hard to beat and on par with anything else the world had to offer.

At that time I bought me a Nakayama Kiita with Nashiji, Nihon Kamisori and Maruka and Maruichi stamp.
It has been my favourite natural stone until I got the Shoubudani.

Let me share with you my experience with three of the five most sought after quarries.

• Nakayama,
• Shoubudani and
• Ozuku

Of course this will only apply to my stones with their individual charakter, but maybe we can find common denominators if you share your experience as well!

I had been happy a long time with my Nakayama Kiita. It gives outstanding edges but needs a very good prepolish. It works a tad slow, but usually in 50 strokes I am where I want to be.
The shaves are outstanding!

After reading the Shoobie-Doobie thread I was interested in one of these Shoubudani from Maksim.
I thought these would make a good addition to my collection as a pre-polisher for my Nakayama.
As soon as I got the stone I knew this thing was harder than my Nakayama Kiita!
And boy, does this thing work.

I was so excited about the Shoubudani and the different charakter compared to my Nakayama,
which for me felt like an improvement, I wanted to see what I could get from one of Maksims super hard Ozukus. And I was not disappointed



I want to encourage to compare the Ozukus you gathered information with.
If you can, compare it to the J-Nats you have in your progressions.
Otherwise leave your comments about your Ozuku. What makes it special?

My ultra j-nat collection





My Shoubudani dark asagi (3) has the following properties:

Colour: dark Asagi, very uniform. Takes on a nice mirrored surface.
Smell: earthy with a hint of cigar smoke
Bought from: JNS, Maksim


Picture




Water only

• works well after an 8k or 10k finish and usually takes less than 40 strokes
• does not diminish a perfect polish under 160x
• has the ability to enhance a polish if the mirror is decent enough (very rare property)
• smoothes out the edge instead of cutting new teeth
• very smooth and oily feedback, very nice
• hairtest back and forth (I am skilled with that test) all day long
• is not very pressure sensitve i.e. you hardly can mess up an edge on it
• shaves right from the stone are outstanding. Easy to use!

With slurry (Tomonagura)

• slurry is hard to raise with a hard tomonagura
• slurry does not get dark quickly
• the slurry feels heavenly smooth and creamy
• the finish is hazy with a touch of mirror. Not bad at all

My old trustworthy Nakayama Kiita with Nashiji (1) has the following properties

Colour: Egshell with a hint of blue (asagi?) and dark spots (nashiji).
Has a line going down the surface that can be typical for Kiita. It does not influence the performance.
The surface is mirrored but not as dense as the Shoubudani or Ozuku.
Has little su (holes) on the surface.
Smell: pure tobacco, moldy and woody. Totally different.
Bought from: hard to tell, I have to check again


Picture




Note: the colour was impossible to catch. Look at the lineup in th efirst picture for colour comparison

Water only

• needs a good prepolish, usually I go there after the Shapton 16k or 12k
• can leave a single scratch every now and then. If used carefully with only a couple of strokes it can be made to leave the finish as is
• Feels very creamy. Different than the Shoubudani and Ozuku for sure
• hairtest back and forth (I am skilled with that test) all day long
• takes a little more skill. Takes a bit longer and the strokes
  need to be consistent.
• shaves right from the stone are outstanding. This is truly a final finishing stone!

With slurry (Tomonagura)

• slurry is quite easy to raise with a hard tomonagura
• slurry gets not dark quickly
• the finish is hazy and slightly scratchy. Still very acceptable

My new Ozuku light Asagi (2) has the following properties

Colour: light Asagi, very greenish, very uniform and beautifully cloudy.
Exciting looks, definitely the most beautiful J-Nat I have.
Takes on a superb mirrored surface.
Smell: earthy with a hint of cigar smoke and tobacco
Bought from: JNS, Maksim


Pictures:


Above the stamp, a wet spot. You can see when wet it turns slightly olive



Water only

• needs a good prepolish, Naniwa 10k usually does the trick
  1 micron lapping film works very good
• hardly diminishes a perfect polish under 160x,
  to the naked eye and loupe no scratches are produced
• smoothes out the edge instead of cutting new teeth
• Feels very hard, yet kind of creamy. Different than the Shoubudani for sure
• hairtest back and forth (I am skilled with that test) all day long
• takes a little more skill to get perfect results. Takes a bit longer and the strokes
  need to be more consistent. But you get rewarded with a perfect (!) edge.
• shaves right from the stone are outstanding. This is truly a final finishing stone!

With slurry (Tomonagura)

• slurry is hard to raise with a hard tomonagura
• slurry gets surprisingly dark quickly
• the slurry feels creamy after a while
• the finish is only slightly hazy with a good mirror. In fact to the naked eye
  the mirror is perfect! Only under magnification is there a scratch pattern visible.
  This is by far the best result I got with slurry, ever. Even the edge coming from the slurry
  is outstanding. I will need to shave of that, very soon

I am extremely excited about my Ozuku. It is probably the hardest stone in my collection,
the second most dense one (after the Shoubudani) and suitable for the final ultra finish.
I believe the Ozuku (at least the ultra hard ones) are for the more experienced sharpener,
whereas the Shoubudani is slightly easier to use, but still gives the best results possible.
Both mines, so it seems, are very underrated!

Heres a little microscope observation. The magnification is about 60x.
Light source is sunlight and remember I did not try to focus on the edge itself,
but on the bevel. Thus the edge can look misleadingly jagged! Trust me, it is not.
I took the pictures through the lense of my microscope.
The pitting spot is always the same throughout the pictures.

First picture: Bevel is set and a good polish is achieved on the Shapton 5k spritzed with 1 µm diamond (my secret for a good polish):



After that the 1 micron lapping film (Al2O3, green) followed:



The edge looked very good, only veeery little teeth present and the HT was positive.
A good shave would be possible.

Here is what the bevel looks like after 100 strokes on the Ozuku
(unnecessary amount, I wanted to see if random particles would be released to mess up the polish)



As you can see the overall polish did not get degraded by an extensive amount of strokes on my Ozuku.
Only very, very shallow single scratches can be made out. But if you look closely, these might have been very well present before the Ozuku.
The sun had slightly shifted by then and this might result in different light angles.



Heres a picture of the finished razor and heavy sunlight


The shave was extremely smooth and close. As good as it gets. No stropping needed