Beginners (soft) Vs experienced (Hard) Jnat

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erezj

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So, in my search after that beautiful (but affordable) Ohira akarenge Suita I had contacted Shinichi to buy #10
http://watanabeblade.com/english/special/wetstone1.htm

I was positively surprised when he kind of refused to sell it to me, yet I did not fully understand his answer, appreciate some clarification:

See Shinichi's answer:
Aoto is several variety grits. But I think it is normaly impossible to use Akarenge after using Aoto.
After using Aoto, you need Kitayama #8000 before Akarenge.
You may choice softer Akarenge. It is easier to use


question #1 - I thought that the Akarenge was around #8000 grit (obviously its a Jnat, so there is a variety) but from the answer above it sounds to me as if its much finer (at least the harder ones), is it really, or did I miss something?
Question #2 - OK, so I know Soft = beginners, Hard = experienced and razors, but why? is it the ability to create mud? you can always use some Nagura, Is it due to pressure control? not to put too much pressure on the thin edge?

I have a few harder Nakayama Koppa's, and I rather like the feedback from hard stones, especially on my Kanna blade

Appreciate your insights
 
Been out of the game a few years but I still use my Jnats for my razors. Soft stones are more forgiving on a slip in technique where a hard stone will remove a portion of edge requiring a start over at times.

This also translates over to synthetic stones as well. I'm sure I'll be corrected if I am not recalling this accurately. I'm also sure there is more to the questions as well.
 
Jnats work through the mud created.
The harder the stone the harder it is to create mud. That is why a nagura is used on some stones to create mud (´get the stone started).
It is not recommended to use nagura on suita stones as larger or less fine particles from the nagura might be caught in the little holes (su). When the stone is then used, the particles may be released and f**k up the polishing/sharpening job.
This makes hard(er) suitas more challenging to use: as you have to work up mud using a consistent angle and so forth.
I have a suita that is so hard I some times struggle a little bit to get it going because I put too much water on it and thus thin the aspiring mud too much. Until sufficient mud is build, the stone doesn´t do much - but it can still dull your edge - which by the time you have reached a hard suita - has taken some effort allready. My hardest suita is supposed be abel to create an almost perfect kasumi finish but I can´t make that happen... (1400 USD stone - so I suppose it is up to me).
The pressure is definitely also an aspect. Harder stones seems in general to be less forgiving.
- Kim
 
+1 to the above. I have a few harder stones and have yet to get a decent slurry. From a pure service perspectice Shinichi is doing you a favor with his suggestions. OTOH how can you learn if you don't try?
 
Jnats work through the mud created.
The harder the stone the harder it is to create mud. That is why a nagura is used on some stones to create mud (´get the stone started).
It is not recommended to use nagura on suita stones as larger or less fine particles from the nagura might be caught in the little holes (su). When the stone is then used, the particles may be released and f**k up the polishing/sharpening job.
This makes hard(er) suitas more challenging to use: as you have to work up mud using a consistent angle and so forth.
I have a suita that is so hard I some times struggle a little bit to get it going because I put too much water on it and thus thin the aspiring mud too much. Until sufficient mud is build, the stone doesn´t do much - but it can still dull your edge - which by the time you have reached a hard suita - has taken some effort allready. My hardest suita is supposed be abel to create an almost perfect kasumi finish but I can´t make that happen... (1400 USD stone - so I suppose it is up to me).
The pressure is definitely also an aspect. Harder stones seems in general to be less forgiving.
- Kim

Would love to see a picture of your super duper uber stone
 
I'm not sure I quite comprehend Shinichi's answer either, at least in reference to the aoto bit. The man knows what he's talking about, though I've found on rare occasions, things get lost in communication. What exactly did you ask him?

As far as my own experience has lead me, I have used multiple ohira suitas ranging from moderate to hard levels of hardness after numerous types of mid-level stones, ie aizu, ikarashi, aoto. Not sure what he means by the statement that its not possible to use after aoto or that you would need a synthetic 8000 in between. Anybody else have any thoughts? FYI, ohira suita can be vary, but usually 5000-7000, sometimes stretching up to 8k. I have one that feels harder like an okudo and might be even finer than 8k, but I can't quite decide.
 
This is just a bit too confusing for me...I look at Maxims pictures of the amazing Sunashi, I see pure black swarf with no mud (you see that a lot with Suitas pictures by pros),
so if I go back to why are hard stones for advanced users? then the ability to create mud easily -> to enhance the 'Shaping power' should not be that crucial, it seems that the pros get the swarf without any mud...

And yet Kim, which is no beginner, finds it hard to use...so why?

Hope my repeating question is not too much, but these stones are expensive! really dont want to pay $500 and have a pretty stone in the drawer....
(eventually I'll just ask someone I trust to chose the stone for me, but still, would love to understand better)
 
@tgfencer My guess would be relative depth of scratch pattern and the suita having to take a long time to fully take out aoto scratches. Makes me want to go and play around with my Aoto slurry on Binsui -> Ohira Suita progression again to check if I actually got to a finish fully reflective of the suita on both the cladding and core steel.
Miles of Aranyik has suggested going from a 1k synthetic stone then to the Thai Orange Binsui (which is roughly in the 'same' grit range) then the White Binsui. Despite similar grit range, they're doing more refinement than fast metal removal.
Maksim's given a similar suggestion when I bought a lvl 4 Aiiwatani from him. Given, it feels a fair bit finer than Ohira suita, but he did advise to jump off to the finisher Jnat from a 6-8k synthetic. Naturals are supposed to create shallower scratches than the synthetic stones, so the fine synths will help bridge the gap somewhat closely to not spend forever on the Jnat finisher to fully take out other scratch patterns.

@erezj when you are sharpening the wide bevel of a knife as Maksim does in his photos and videos you have much more surface area to help kick up swarf and mud. Not so when just hitting a ~1mm primary bevel. And at least to me as still a relative novice to natural stones, it feels weird to refine the edge on a very small bevel without any slurry for aiding cutting and feedback. I still don't sharpen the edge as well on glass-hard stones compared to softer feeling ones - a skill/technique gap.
Would probably not recommend spending $500 on first Jnat...
 
Yeah, that makes sense! I just dislike going to a synthetic in the middle of a natural progression, ruins the vibe. :) Tend to prefer starting on them though, for the courser grit ranges.

I also tend work through a good amount of mud refinement on my middle stones though, so the edges end up pretty close to my suita range. For instance, going from an aoto to my ikarashi ends up at close to 4K after refinement, which makes the jump to my softer ohira not too big. But if I were being perfectionist about it, I would want to stick something in between.
 
@tgfencer particularly for folks just wanting a finisher Jnat or just getting into naturals and starting with fine stones, that advice is good for understanding how the natural fits in.
I'm doing something similar to you when starting from coarse stones in a progression.
Based on your aoto and your Ohira suita, would you make the jump if you didn't have the Ikarashi?
 
I feel with hard jnats you need to have a much better control and light pressure. I understood Watanabe san is saying that you will need another stone between an aoto and the stone you are trying to buy from him. Besides, he's suggesting you get a softer stone too. I agree that the only way to learn is to try, but if you are starting with jnats, it might be frustrating to use a hard stone.
 
Based on your aoto and your Ohira suita, would you make the jump if you didn't have the Ikarashi?

Mmm, tough one. Probably not, particularly with wide bevels. This aoto is a bit harder than most I think, but I'm not sure I'd want to work that much on the ohira. If I was just looking for a quick finished edge on a microbevel and wasn't worried about removing all scratches from previous grits, then possibly.
 
@erezj you can try your Nakayama koppas on a kitchen knife's small primary bevel, see the swarf/ mud development, let the stone dry, and then do the same with your kanna blade, see if there's a difference in what happens
 
I have almost the exact stone (as 10) from Shinichi except thinner (15mm). Let me see if it's really that hard
 
By the way, erezj, do you already have an aoto? I feel i good aoto is awesome to kitchen knives, leaving a lot of teeth.

Thanks Marcelo for the answers, as for your question, well I have two Aoto's, one cheap from MM, nice but since I bought a much refined one from Maxim, thats my go to stone.
I have a set of three Shun's which I use the Aoto as the final stone (nice tooth, love the edge), but with my carbons, Heiji and Shig, I usually continue to one of the Nakayamas + Nagura combination (I got the set of three from Maxim).

Still looking for the best combination for for that ever eluding perfect edge (I enjoy the chase)
 
Having these stones I understand Shinichi. You can do things like Ai1000, 8000 and then Aka renge, you will get a clean "aka renge " finish quick.
But Aka has too little shaping power to polish middle or coarse grit.
In a way 8000 synth helps to make the sharpening more effective removing rough surface.
I see this stone as a quick "pass" for fine jnats (from hardness 5/10)
 
@erezj you can try your Nakayama koppas on a kitchen knife's small primary bevel, see the swarf/ mud development, let the stone dry, and then do the same with your kanna blade, see if there's a difference in what happens

There is obviously a huge difference ! when I sharpen my Heiji (wide bevel) I get much more swarf, same as with the Kanna, I assume its 99% softsteel, but the mud it creates helps with that 1% which is the cutting edge.

when I run the Shig, I will usually create some mud with nagura first.
 
I just tried my stone that is very similar to the stone your are after... almost identical except mine is thinner.

Its soft enough to create mud on it's own.. not that fatest to generate mud but shouldn't be an issue and not nagura required

leaves a good edge on the knife
 
I believe what he is saying is that the stone you were considering is far too hard (and hence slow cutting) to jump from an aoto to working on it to get a good finish in a reasonable time. The use of a synthetic stone before, even at the same grit, will do all but the polishing.

The point of saying you need more experience before using hard naturals is simply that they cut VERY slowly, and unless you can maintain very good or excellent angle control for long periods of time (ten minutes or more!) without a single too high wobble, you are going to undo a lot of work on lower grit stones by rolling the edge over or making an un-intended micro bevel.

Never going to be a problem for me, as I won't ever be spending that much money on a stone, but if you are, take the advise of the seller, he knows what he's talking about.

Peter
 
I generally always use my jns 6k before my natural finishers. Even if just for touch ups, a few passes on a 4-6k synthetic, before moving onto your suita or awasedo will benefit.
 
During touchups- The crumbling/rolling a thin edge by accidentally hitting at a higher angle than the bevel is at is something that's been kicking my butt a bit recently moving onto more naturals (slower cutting) and in general harder finishers without good slurry buffer/faster cutting action
 
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