# Wide Bevel and Shinogi



## 4wa1l (Dec 13, 2020)

I have a wide bevel Togashi gyuto that I would like to thin and sharpen as you would a single bevel with a hamaguri convex and microbevel, maintaining the thinness behind the edge each time I sharpen. I started to thin it down and straight away could tell that it isn't as even as the shinogi would make it seem (I know I need to work on my skills and there are some scuffs above the line definitely due to my inconsistent angles).

I have added photos of the most inconsistent side to see what is the recommended course of action before I go further. I marked what looks and feels like a high spot with the red arrow. I assume this is fairly simple and I would continue to focus on this area until it aligns with either side.

The green arrow points to the area that concerns me most. It appears like a low spot as there are still factory scratches here but the shinogi is also closest to the spine. Does that mean I have to focus on the rest of the bevel and bring everywhere else up in line with this before I can rectify it?

I understand that I could probably just go for it and ignore the line but it looks so nice when it's straight. I've knocked down the large secondary bevel it came with and it cuts well as is but I guess I want to maintain the aesthetics of the knife.

This was mainly done with a Morihei 500 which seems to hide a lot of the low spots until I move up to the chosera 800. Is it worth investing in a lower grit stone to speed things up or is it a bit risky? I also find that the stone dishes relatively quickly and know that I might have the same issues with a coarser stone.

Any advice would be greatly appreciated!


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## zizirex (Dec 13, 2020)

wide bevel will benefit by using a very flat stone. it's also nice to check if the Hira is flat, but I wouldn't bother with that if you don't want to mess up the looks and finish. A little low spot is fine, if the shinogi is too high your bevel is much thinner and a little more fragile.


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## 4wa1l (Dec 14, 2020)

Thanks for the response! I try to keep my stones flattened but the 500 seems to dish pretty quickly. My chosera stays flat but it's a higher grit. I guess that's why I asked about a different stone. Maybe something else coarse that stays relatively flat if that exists? Would sandpaper also work on a flat surface?

I had not thought about the hira being flat. I guess I could tape it off and sand it if I messed it up but the current finish is pretty nice. Ideally I'd leave that alone for the time being. 

If I try and be even and consistent along the whole blade when I sharpen, is the wavy shinogi likely to even out eventually? Or do you really have to focus on uneven spots? The knife cuts fine and as soon as patina sets in you can hardly see the shinogi. It would just be nice to have a flatter and more even kireha mainly for polishing purposes.

I realise I've asked another bunch of questions but I am very keen to learn : )


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## nakiriknaifuwaifu (Dec 14, 2020)

4wa1l said:


> Thanks for the response! I try to keep my stones flattened but the 500 seems to dish pretty quickly. My chosera stays flat but it's a higher grit. I guess that's why I asked about a different stone. 1. Maybe something else coarse that stays relatively flat if that exists? 2. Would sandpaper also work on a flat surface?
> 
> I had not thought about the hira being flat. I guess I could tape it off and sand it if I messed it up but the current finish is pretty nice. Ideally I'd leave that alone for the time being.
> 
> ...



My 0.02USD/0.027AUD answering your questions:

1: coarse stone that stays flat = diamond plates or vitrified diamond. Also, if you're just doing maintenance thinning as you go, you shouldn't even need your 500.
2: Wet/dry sandpaper works, and it's what I use (cuz it's relatively inexpensive)
3: If the blade has curves or warps - and most japanese blades do - it will not even out. If the blade was hand finished on stones then you'd know what would be possible. Not sure about this knife, maybe someone can chime in.
4: If the blade is fine, then yes you would have to focus on trouble spots and doing things evenly. One tip from JKI for working on things evenly is to use marker on the whole bladeroad, thin just enough rub it off, paint the bladeroad with marker again, repeat, etc. That'll keep you accountable.


It's really tough to do a proper and even hamaguri bevel. Good luck and enjoy the journey.


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## 4wa1l (Dec 14, 2020)

nakiriknaifuwaifu said:


> My 0.02USD/0.027AUD answering your questions:
> 
> 1: coarse stone that stays flat = diamond plates or vitrified diamond. Also, if you're just doing maintenance thinning as you go, you shouldn't even need your 500.
> 2: Wet/dry sandpaper works, and it's what I use (cuz it's relatively inexpensive)
> ...



Hopefully I would get it to the point where the 800 is as low as ever need to go. It seems to give a nice starting contrast too. I might try some 400 sandpaper and a marker to see how things look.

I'm pretty sure this wasn't hand finished on stones. It has/had deep scratches on the bladeroad that run pretty much parallel to the edge.

Maybe even after the bladeroad is relatively flat or has a bit of convex lI'll have to use tape if I really want to have a crispy shinogi. I reckon that's probably what was done at the factory. 

I know I'm aiming high but it seems like the hamaguri bevel would suit this knife well. Thanks for the advice!


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## 4wa1l (Dec 14, 2020)

It would be cool to see some used and sharpened wide bevels to see how they look. I'm thinking Kagekiyo's and older style Konosuke wide bevels.


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## zizirex (Dec 14, 2020)

yeah Morihei 500 dish pretty quick if you're doing rough work, that's why I don't stay in 1 spot. I have a DMT 220 that's has been abused, so it's much finer now and it stays flat. also, try to even out your pressure on the bevel and on the core because the soft steel and hard steel cut at a different rate.


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## Nemo (Dec 14, 2020)

That doesn't really look too bad.

Unless aesthetics are much more important to you than performance, I really wouldn't try to fix the shinogi or low spots in one sitting- its a huge waste of steel. Just thin it when it needs thinning and gradually fix the shinogi/ low spots.

I wouldn't be using a 500 stone on it at this stage unless you are determined to try to fix the geometry in one go.

If you really hate the aesthetic, you could touch up the top (knife flat) side of the shinogi with a rust eraser or a little wet (and dry) sandpaper, used wet. Looking at your blade finish, I'm guessing the flat is finished at maybe p600. I'd start a little finer, maybe p800, attending only to the mm or so that the wide bevel encroaches above where the shinogi should be.

Personally I would just use the knife.


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## 4wa1l (Dec 14, 2020)

Nemo said:


> That doesn't really look too bad.
> 
> Unless aesthetics are much more important to you than performance, I really wouldn't try to fix the shinogi or low spots in one sitting- its a huge waste of steel. Just thin it when it needs thinning and gradually fix the shinogi/ low spots.
> 
> ...



I did want to get it thinner behind the edge because it came with a solid secondary bevel which seemed out of place. I hoped this style of sharpening would achieve that and also let me muck around with different finishes while maintaining the thinness. Given how clean it looked ootb I was surprised to see the shinogi change so quickly and also reveal the uneven spots. I did manage to substantially reduce the shoulders of the secondary bevel without removing much steel from the edge which was great. It's cutting much nicer than it did too which I'm very happy about.

This is it now so it's certainly being used (got a sweet new handle for it too if anyone remembers the old pics). It is a bit futile I guess but I enjoy the process even if the finish is so temporary.






I was game to try and keep it pretty but it does seem a bit stupid wasting metal when it works well as is and should eventually even out more. Probably best to spread it over a few sessions like you say. I think I'll have to reduce my expectations too.


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## jwthaparc (Dec 14, 2020)

Where you put pressure, and variations in the amount of pressure you put with your fingers can cause the shinogi to be wavy. 

I have a tojiro shirogami santoku that came sandblasted, so it looked like there was an actual shinogi line. The grind was actually flat the whole way down though. The reason I bring that up, is because it doesn't have a real shinogi it makes a giant difference when I get off on my finger placement and pressure.


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## naader (Dec 27, 2020)

If your hira is not dead flat, your shinogi line will likely have a wobble. There are a few ways of grinding hamaguri on a wide bevel and almost all of them, at one point or another, require some sort of longitudinal stroke to keep the shinogi straight.
It is absolutely not necessary to have very flat or hard stones to do this, you just have to be conscious of your position, pressure and the current state of the kireha and hira. I do most of my work on slightly convexed stones.

One thing I like to do is flatten the top half of the kireha towards the shinogi and convex the bottom half towards the edge. I put this sort of grind on most of my single bevels, with more convexity at the heel and gradually less as I reach the tip. This I feel is easier because the flattest contact on the kireha will be touching the shinogi. This way you can put parallel scratches just below the shinogi really easily.

All of this aside, I think your knife most likely doesnt have a flat hira, which is partly why the shinogi looks like that.


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## Robert Lavacca (Dec 27, 2020)

T


naader said:


> If your hira is not dead flat, your shinogi line will likely have a wobble. There are a few ways of grinding hamaguri on a wide bevel and almost all of them, at one point or another, require some sort of longitudinal stroke to keep the shinogi straight.
> It is absolutely not necessary to have very flat or hard stones to do this, you just have to be conscious of your position, pressure and the current state of the kireha and hira. I do most of my work on slightly convexed stones.
> 
> One thing I like to do is flatten the top half of the kireha towards the shinogi and convex the bottom half towards the edge. I put this sort of grind on most of my single bevels, with more convexity at the heel and gradually less as I reach the tip. This I feel is easier because the flattest contact on the kireha will be touching the shinogi. This way you can put parallel scratches just below the shinogi really easily.
> ...


Thanks for this info. This saves me from messaging you on Ig with a million questions .


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## naader (Dec 27, 2020)

Robert Lavacca said:


> T
> 
> Thanks for this info. This saves me from messaging you on Ig with a million questions .


I'm always more than happy to answer questions haha


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## ian (Dec 27, 2020)

naader said:


> It is absolutely not necessary to have very flat or hard stones to do this, you just have to be conscious of your position, pressure and the current state of the kireha and hira. I do most of my work on slightly convexed stones.



Convexed is better than concave, though, which is the OP's problem. A concave stone can scratch above the shinogi more easily and make it more difficult to control where the knife is contacting.


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## naader (Dec 27, 2020)

ian said:


> Convexed is better than concave, though, which is the OP's problem. A concave stone can scratch above the shinogi more easily and make it more difficult to control where the knife is contacting.


Could be, but the degree to which the shinogi has been driven up in specific spots still makes me lean towards minor bends or an uneven hira


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## ian (Dec 27, 2020)

naader said:


> Could be, but the degree to which the shinogi has been driven up in specific spots still makes me lean towards minor bends or an uneven hira



Oh, sure, I’d guess that too. Just saying I prefer nonconcaved stones for wide bevel work.


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## 4wa1l (Dec 28, 2020)

naader said:


> If your hira is not dead flat, your shinogi line will likely have a wobble. There are a few ways of grinding hamaguri on a wide bevel and almost all of them, at one point or another, require some sort of longitudinal stroke to keep the shinogi straight.
> It is absolutely not necessary to have very flat or hard stones to do this, you just have to be conscious of your position, pressure and the current state of the kireha and hira. I do most of my work on slightly convexed stones.
> 
> One thing I like to do is flatten the top half of the kireha towards the shinogi and convex the bottom half towards the edge. I put this sort of grind on most of my single bevels, with more convexity at the heel and gradually less as I reach the tip. This I feel is easier because the flattest contact on the kireha will be touching the shinogi. This way you can put parallel scratches just below the shinogi really easily.
> ...


Thanks for your input! That is very interesting reading about the subtleties of your hamaguri grind. I will come back to this post next time I sharpen it. Maybe one day I will try and flatten out the hira but it seems like more work than I am prepared to do at this stage.


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## nutmeg (Dec 28, 2020)

You need a stone that is convex at its extremities, About 2cm should be ok. No need for a steep convexity.
And the flat part of the stone has to be kept flat very, very, very often during the reshaping of the blade.

Work slowly, watch the blade often and don't be afraid to use much pressure. Even 5-10kg is ok.
Try to go with higher grits and parallel to the length of the edge as soon as possible for a really straight shinogi line. Diagonal can't give you perfection for this.


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## TB_London (Dec 28, 2020)

It’s really easy with uneven pressure to introduce that sort of wobble. Especially when flattening on stones for the first time as you have the grind unevenness to contend with. 
Flatten your stone and then work consciously with finger pressure over the shinogi, regularly stopping and checking till you have it even. This will give some convexity to the bevel which is fine. You shouldn’t be rocking the knife on the stone, just putting pressure where you need it.


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## jwthaparc (Dec 28, 2020)

I'm thinking about adding a hamaguri shape on my double bevel gyuto. Do you guys think I should do it asymmetrically on the right side leaving the left side flat or add convexity to both sides? What would the benefits be for one over the other?


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## Nemo (Dec 28, 2020)

jwthaparc said:


> I'm thinking about adding a hamaguri shape on my double bevel gyuto. Do you guys think I should do it asymmetrically on the right side leaving the left side flat or add convexity to both sides? What would the benefits be for one over the other?


Which gyuto? What grind does it have?

I admire your sense of ambition.

If it's not already convexed, it's gonna be a lot of work. And will take some skill to get right. And you will necessarily lose a bit of blade height.

I'd consider just buying a convex wide bevel instead. Then you can hamaguri to your heart's content.

Some examples to look at include Wakui Tsuchime, Yoshikane Tsuchime (not the nashiji) and Mizuno Akitada Hontanren wide bevel. I'm pretty sure Gihei HAp40s have a bit of convexity as well, likewise Kurosaki Syousin Chiku Migaki (unsure about the KU version), although I haven't thinned mine yet, so not 100% sure.


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## jwthaparc (Dec 28, 2020)

Nemo said:


> Which gyuto? What grind does it have?
> 
> I admire your sense of ambition.
> 
> ...


It's a tojiro shirogami 2 kurouchi gyuto. It's got a flat wide bevel. I don't mind doing some extra work on it now, and since I've been messing with fingerstones lately I actually have to ability to get a decent finish on it without driving myself insane trying to get it perfect directly off of my stones.


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## nutmeg (Dec 28, 2020)

jwthaparc said:


> I don't mind doing some extra work on it now, and since I've been messing with fingerstones lately I actually have to ability to get a decent finish on it without driving myself insane trying to get it perfect directly off of my stones.



Finger stones always damage the geometry.
I bet once your shinogi will be straight, crisp and maintained this way, a time will come when you won't use them anymore.


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## jwthaparc (Dec 28, 2020)

nutmeg said:


> Finger stones always damage the geometry.
> I bet once your shinogi will be straight, crisp and maintained this way, a time will come when you won't use them anymore.


Idk if I can get it straight in this knife. It's a kurouchi knife, and the hira is pretty far from being flat. Which I'm fine with in this case because it sort of goes with the look of the knife. 

Do fingerstones tend to just round the shinogi, or can the geometry be effected in a more substantial way by them?


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## M1k3 (Dec 28, 2020)

Finger stones tend to follow unevenness.


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## Luftmensch (Dec 28, 2020)

jwthaparc said:


> Do fingerstones tend to just round the shinogi, or can the geometry be effected in a more substantial way by them?



Finger stones are very gentle but they can change the geometry slowly. This is particularly true for fine features. They are primarily used for aesthetics.

If you have a very sharp, well defined shinogi, finger-stones can round it over. But there are finger-stones and there are _finger-stones_. For polishing, very thin finger-stone are adhered to a soft backing. You then crack the thin stones so they can flex at the crack - this allows the '_flexible_' stone to follow the shape of the steel. Alternatively you can use a small piece of thicker, _rigid_ stone. Use this for detail work (instead of a bench stone) when you are working on flat steel. A thick slurry will fill dips and help camouflage them.

To prevent the shinogi rounding over, use a _rigid_ finger-stone at the shinogi. Make sure the stone follows the angle of the blade road just before the shinogi. Take extra care that you dont abrade the shinogi line with the stone (i.e. dont lower the angle of the stone so that it approaches the face of the blade), this will round over the line.


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## nutmeg (Dec 29, 2020)

Fingerstones are only for final make up. Say 1% of the job.
After benchstones the surface should be already 99% of what you‘re looking for.
If you do it this way the damage appeared on the geometry shouldn‘t be visible.
And you should always use only very thin finger stones. Otherwise you‘ll get a scratchy surface. Trying to avoid the shinogi with them is very challenging anyway. And once again, if your blade is already top you don‘t need much work or pressure with the finger stones.
And generally on a scratch pattern that is diagonal to the length of the blade finger stones don‘t give very good results.


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## jwthaparc (Dec 29, 2020)

Back to my original question should I do hamaguri asymmetrical, or symmetrical? Asymmetric convexing seems like it could add the best of both worlds, I could be wrong though. I actually went ahead and convexed one side yesterday, I'm waiting to see if I should do the other side today.


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## naader (Dec 29, 2020)

jwthaparc said:


> Back to my original question should I do hamaguri asymmetrical, or symmetrical? Asymmetric convexing seems like it could add the best of both worlds, I could be wrong though. I actually went ahead and convexed one side yesterday, I'm waiting to see if I should do the other side today.


It really comes down to your personal preference. There is no "should", there's just what you like and don't like. My 2 best cutters are a shig gyuto which is pretty damn symmetrical and a wide bevel konofuji that's definitely not. Both have different places they shine. Tailor the knife to the way you want to use it, not to the opinions of randoms online.


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## ian (Dec 29, 2020)

jwthaparc said:


> Back to my original question should I do hamaguri asymmetrical, or symmetrical? Asymmetric convexing seems like it could add the best of both worlds, I could be wrong though. I actually went ahead and convexed one side yesterday, I'm waiting to see if I should do the other side today.



Probably won’t matter a ton. A bit of convexity on the left side can also be useful for food separation, though. Just make sure the core steel is more or less centered, whatever you do.


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## jwthaparc (Dec 30, 2020)

naader said:


> It really comes down to your personal preference. There is no "should", there's just what you like and don't like. My 2 best cutters are a shig gyuto which is pretty damn symmetrical and a wide bevel konofuji that's definitely not. Both have different places they shine. Tailor the knife to the way you want to use it, not to the opinions of randoms online.





ian said:


> Probably won’t matter a ton. A bit of convexity on the left side can also be useful for food separation, though. Just make sure the core steel is more or less centered, whatever you do.


Alright, I'm going to leave it with the convexity I added to the right side, and see how I like it. I've had good experiences with it on both sides already, and would love to see how it performs.


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