# Thinning Masakage Koishi gyuto bevel



## mav.s (Aug 29, 2020)

Gathering some member opinions for my 210mm Masakage Koishi Gyuto, Aogami Super core steel with stainless cladding. It has a great edge OOTB, and crazy sharp after a quick touch up on Rika 5000 and strop. But I have noticed it wedges on certain vegetables, especially compared to my Yuki nakiri. Wondering if others have had the same feedback on Koishi knives? You'll see from the choil shot there's a noticeable secondary bevel line more than halfway down the blade. Read a few other member posts on the same knife and their shinogi lines I recall were smoother form top of bevel to edge. Opening this poll to help me decide whether to slim this baby down! Thanks all!


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## mav.s (Aug 29, 2020)

Oh, I should add
the weight is 150g.


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## kayman67 (Aug 30, 2020)

I'm not fully awake, but looks like some kind of S grind.


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## Bear (Aug 30, 2020)

I did thin my 180 but be ready, its allot of work, the grind on mine was convexed so the shinogi line had to come way up. If your looking for a good project go for it. For me it was worth it, I really like the AS on these, easy to sharpen and they hold an edge forever.


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## mav.s (Aug 30, 2020)

That’s kind of what I was afraid of / expecting. What did you use to remove your convex? I have a shapton pro 120, sigma 400, king neo 800 or cerax 1000 and Rika 5000. Did you have a nice contrast after thinning? Would love to see a pic too if you can share.


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## applepieforbreakfast (Aug 30, 2020)

I thought these were concave on the wide bevel?


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## mav.s (Aug 30, 2020)

I do see a bit of concave on mine. Food release isn’t much of a problem, but I think it’s the profile grind from top to secondary bevel that is creating the wedge feel.


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## Carl Kotte (Aug 30, 2020)

Judging from the pictures this knife looks thin to me. Have you measured it with a caliper? 
Here’s an idea. The wedging effect you’re experiencing could be something else I’ve noticed on some wide bevel knives. While they are quite thin, it feels like they wedge because they get ’stuck’ in produce while cutting. The contact areas between produce and the wide bevels can be quite big after all. Might that be what you’re experiencing too?


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## M1k3 (Aug 30, 2020)

Carl Kotte said:


> Judging from the pictures this knife looks thin to me. Have you measured it with a caliper?
> Here’s an idea. The wedging effect you’re experiencing could be something else I’ve noticed on some wide bevel knives. While they are quite thin, it feels like they wedge because they get ’stuck’ in produce while cutting. The contact areas between produce and the wide bevels can be quite big after all. Might that be what you’re experiencing too?


+1
Flat surface versus stiffer produce creates a suction effect.


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## esoo (Aug 30, 2020)

Every grind is a balance so thinning the Koishi will improve its performance in some veg, but it's performance will go down in others. 

Use the knives and you'll figure out that you'll prefer a certain on for certain veg. Never a problem to switch in prep


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## Bear (Aug 30, 2020)

M1k3 said:


> Flat surface versus stiffer produce creates a suction effect.



Mine is just a 180, for what it's used for it's not a problem, that being said, the grind is allot closer to flat plus, with a mirror finish things can get sticky.


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## M1k3 (Aug 30, 2020)

For flat bevels/faces, I like to use a variation of Jon's hamaguri sharpening.


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## JDC (Aug 30, 2020)

A concave wide-bevel would be painful to flatten. The wedging will be relieved if you just thin the area behind the edge. The large, high-angle secondary bevel is what caused the wedging. Food release will still be a problem for some produces say zucchini.


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## ian (Aug 30, 2020)

JDC said:


> A concave wide-bevel would be painful to flatten. The wedging will be relieved if you just thin the area behind the edge. The large, high-angle secondary bevel is what caused the wedging. Food release will still be a problem for some produces say zucchini.



I'm inclined to agree with this. The knife looks like it is a little fat in the 1mm next to the edge, but the concave wide bevel looks fine. I wouldn't mess with that unless you really just want a project for some reason.


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## ModRQC (Aug 30, 2020)

I would have questions about this myself, but don't want to hi-jack OP. Let's say I'm reading avidly into this post.

I do have a question related to what's been posted so far: I know it might depend on the geometry, but @Carl Kotte idea to measure with a caliper, how high should I generally want to go over the edge and look that I have consistent thinness, and what would generally be an ideal thickness behind the edge?


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## ian (Aug 30, 2020)

@Benuser likes to say .2mm at the top of the primary bevel, .5mm at 5mm from edge, 1mm at 10mm from the edge. I've found these to be useful and instructive ballpark measurements to shoot for, although I think these are more lasery than some knives. I often find that .7mm at 5mm from the edge and 1.1 or so at 10mm works just fine, too.


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## Carl Kotte (Aug 30, 2020)

Yes, those are the relevant Numbers. Unless my calipers are wrong (or I read them incorrectly) only one knife I own came with those dimensions: my Y Tanaka. All others have been thicker. Some much much thicker, some pretty close to those measurements. I agree with Ian that 0,6 at 5 and 1,1 (up to 1,3) can work very well too.


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## ModRQC (Aug 30, 2020)

And this is always consistent, or do you guys allow for "natural tapering", e.g. have stiffer measurements as closing down to the tip?


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## JDC (Aug 30, 2020)

ModRQC said:


> And this is always consistent, or do you guys allow for "natural tapering", e.g. have stiffer measurements as closing down to the tip?



Depends on what do you cut, for common vegetables (not too tall), I find it’s more important to be thin towards the tip, workhorse knifes does this can perform as well as lasers (or better because of the weight) on many produces.


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## ian (Aug 30, 2020)

ModRQC said:


> And this is always consistent, or do you guys allow for "natural tapering", e.g. have stiffer measurements as closing down to the tip?



Not sure what you mean by stiffer measurements. But it depends what you want from the knife. If the measurements are more or less distally constant, then the knife will have a consistent feel in cutting all the way down the edge. Sometimes it’s advantageous to have a thicker heel (eg in some butchery knives where you may want to go through bones with the heel, and use the tip for precision work), in which case the measurements may become smaller as you go toward the tip. Up to preference.


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## Ryndunk (Aug 30, 2020)

Definitely a concave grind. I have a kioshi 300 sujihiki. Had to flatten and thin the bevels after I chipped it pretty good on a bone that happened to be in a "boneless pork loin". Takes quite a bit of work. Thinning stainless sucks. Shouldn't be to bad for a 210 though. Think I broke it up into 2 sessions. Just use sandpaper to finish the bevels if you don't get all the low spots on your first attempt.


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## ModRQC (Aug 30, 2020)

Thanks for the lights guys.

A last question would be : once the 10mm above the edge are corresponding to rule of thumb, how important it is that the rest of the bevel above that so to speak is consistent, and what are the best tricks to detect and correct an « uneven » job?


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## ian (Aug 30, 2020)

Oh, also, I think for most wide bevels the numbers are pretty constant distally, since if there’s a lot of distal taper and variation in the grind, then it can be hard to make the shinogi line look good.


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## ModRQC (Aug 30, 2020)

Sandpaper for correcting I can do that for sure, looking to know about alternatives.


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## ModRQC (Aug 30, 2020)

ian said:


> Oh, also, I think for most wide bevels the numbers are pretty constant distally, since if there’s a lot of distal taper and variation in the grind, then it can be hard to make the wide bevel look good.



Makes perfect sense.


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## JDC (Aug 30, 2020)

JDC said:


> Depends on what do you cut, for common vegetables (not too tall), I find it’s more important to be thin towards the tip, workhorse knifes does this can perform as well as lasers (or better because of the weight) on many produces.


 Sorry I meant towards the edge, not the tip... For differential grind along the length, it depends on the type of the knife, usually multi-functional knives such as Gyutos will benefit from thinner tip and thicker heel.



ModRQC said:


> Thanks for the lights guys.
> 
> A last question would be : once the 10mm above the edge are corresponding to rule of thumb, how important it is that the rest of the bevel above that so to speak is consistent, and what are the best tricks to detect and correct an « uneven » job?



Thin at 10mm still can wedge if behind the edge is not thin enough. At 10mm it’s more related to how food release will work, usually I start a pronounced convexing at 10mm to aid that.


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## mav.s (Aug 30, 2020)

For those suggesting flattening down the transition between the top and secondary bevel, how much would you recommend sanding down? I agree with not messing with the wide bevel because of the concave.


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## M1k3 (Aug 30, 2020)

M1k3 said:


> For flat bevels/faces, I like to use a variation of Jon's hamaguri sharpening.



3 and 4 are hitting the top of the shinogi. Fingers placed near the top.

5 and 6 are hitting near the edge. Fingers placed as close to the edge without creating a skin burr/red lubricant.



















Sorry for the crappy pictures. Hopefully I convey the idea.


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## M1k3 (Aug 30, 2020)

mav.s said:


> For those suggesting flattening down the transition between the top and secondary bevel, how much would you recommend sanding down? I agree with not messing with the wide bevel because of the concave.


Enough to smooth it out, break up the flatness.


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## Benuser (Aug 30, 2020)

ian said:


> @Benuser likes to say .2mm at the top of the primary bevel, .5mm at 5mm from edge, 1mm at 10mm from the edge. I've found these to be useful and instructive ballpark measurements to shoot for, although I think these are more lasery than some knives. I often find that .7mm at 5mm from the edge and 1.1 or so at 10mm works just fine, too.


Agreed. I tend to suggest them as values to aim for, as a rule of thumb, and easily to be remembered.


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## ModRQC (Aug 30, 2020)

What is your approach of grits vs work to do. In four months of practice, I can sharpen, but as to assess metal removal rate as I go seems to be beyond me for now. Say I have a knife where I need to remove .2 to .5 mm to get within thumb rule, what grit would you start? I’m thinking about using NP800 for that last part of the job, not going too agressive because it doesn’t seem like much steel to me, but perhaps it’s too high and will take too much time?


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## McMan (Aug 30, 2020)

I think I'm in the minority here... I'm not seeing a ton to thin.
There's not too much meat behind the edge here:





Rather, I think this knife falls into the "doesn't mesh well with you" category. Wide bevels can wedge at times through tall hard stuff. It's the nature of the beast and a trade off for what they do well. You could knock the shoulders off (round them and blend that) but then you're more into changing the grind territory as opposed to just thinning. Plus, you're in trade-off territory--blending the shoulders on this particular knife would likely make food release worse (since you'd be lessening the division between the two concavities) but would improve against wedging.

From the choil shot, it looks like the knife has a neat grind that's somewhat uncommon--a sort of double-concave S-grind. Thinning or no, I have a feeling this knife will not perform in the way you want, and that this is mostly about the grind. So, either figure out what it excels at for you and use it there or sell it and grab something more akin to what you're looking for. Or, thin it and see what's up.

Edit: I guess I'm not in the minority... I just checked the poll


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## Benuser (Aug 30, 2020)

ModRQC said:


> What is your approach of grits vs work to do. In four months of practice, I can sharpen, but as to assess metal removal rate as I go seems to be beyond me for now. Say I have a knife where I need to remove .2 to .5 mm to get within thumb rule, what grit would you start? I’m thinking about using NP800 for that last part of the job, not going too agressive because it doesn’t seem like much steel to me, but perhaps it’s too high and will take too much time?


I'd say, that's a lot of steel to get removed. Don't be afraid of coarse stones. They allow you to remove steel without a lot of pressure. Better than a less coarse stone needing huge pressure. But make sure to stay away from the very edge.
Another option were automotive sandpaper. Works very fast. Again, stay away from the very edge. If it has been touched with a coarse grit a lot of work is to be done and inevitably some of the edge gets lost. You may end with a narrower blade with the same thickness behind the edge, and all work be done in vain.
P.S. If the steel you want to remove is at the level of the shoulder, where bevel and face meet, it can be wise to avoid coarse stones, as you want the edge to stay untouched. I remember removing shoulders of a Misono Swedish Carbon with a Chosera 2k. Your 800 can be very helpful and all you need. My remarks on coarser grits were about thinning further upward to the spine.


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## mav.s (Aug 30, 2020)

Thanks for all the great feedback! Seems like consensus is to leave it as is. I may do just that and give it some time. Also hoping to hear from other Koishi owners If they have a similar grind or something different.


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## ian (Aug 30, 2020)

McMan said:


> I think I'm in the minority here... I'm not seeing a ton to thin.
> There's not too much meat behind the edge here:
> View attachment 92563
> 
> ...



Hmm, yea in that pic even the near-edge looks pretty thin.


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## mav.s (Aug 30, 2020)

That shot is with the knife pointed slightly down. This ones more representative.


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## ModRQC (Aug 30, 2020)

mav.s said:


> That shot is with the knife pointed slightly down. This ones more representative. View attachment 92565



I had a Kurosaki for a short while that was needle-like resembling this but even farther up the edge. Very laser in some cuts, seemingly wedging in taller or denser produce. I think @M1k3 explained it best when he said it can create suction. Just saying.


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## JDC (Aug 30, 2020)

McMan said:


> I think I'm in the minority here... I'm not seeing a ton to thin.
> There's not too much meat behind the edge here:
> View attachment 92563
> 
> ...



Well, if the op doesn’t want to wedge carrots, the edge is not thin enough, otherwise should be ok


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## Kawa (Aug 30, 2020)

Just a brainfart,

If the knife is a fair bit smaller towards the tip, which seems to be the case in the last picture from the opening post, you might be able to simulate how thinning the knife will handle carrots. Cut a carrot that normally wedges with the part of the blade near the tip, even hold the knife halfway between heel and tip to make the cutting motion a bit more 'natural'. 
You might feel difference in a positive way, or no difference at all.

In the last case that might also be because my brainfart doesnt make sence at all..


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## McMan (Aug 30, 2020)

JDC said:


> Well, if the op doesn’t want to wedge carrots, the edge is not thin enough, otherwise should be ok


If the OP doesn't want to wedge carrots, then a laser would be a good place to start 
To my eye, the issue is not with this knife being thick behind the edge. The reason OP is having wedging seems to me to be an issue of grind/geometry. Wedging is a known side effect.

I'm not seeing much room to thin this knife.




Knocking the shoulders off then blending is a different ballgame than just thinning.


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## JDC (Aug 30, 2020)

McMan said:


> If the OP doesn't want to wedge carrots, then a laser would be a good place to start
> To my eye, the issue is not with this knife being thick behind the edge. The reason OP is having wedging seems to me to be an issue of grind/geometry. Wedging is a known side effect.
> 
> I'm not seeing much room to thin this knife.
> ...



Well, a laser can still wedge a carrot if not taking care of the thickness behind the edge. Such a concave grind makes the OP's knife thinner than most convex knives out there for at least 10mm starting from the edge. It will perform like a laser if the secondary bevel (edge bevel) is thinned.


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## mav.s (Aug 30, 2020)

JDC said:


> Well, a laser can still wedge a carrot if not taking care of the thickness behind the edge. Such a concave grind makes the OP's knife thinner than most convex knives out there for at least 10mm starting from the edge. It will perform like a laser if the secondary bevel (edge bevel) is thinned.



Great point JDC. This is kinda what I'm thinking as well. Might be a good project to smooth out this secondary bevel line. Thanks for all the great feedback! If I decide to move forward, will make sure to document the process.


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## 4wa1l (Sep 30, 2020)

I figured I'd add a post onto here rather than start a new thread, as I have a similar question.

I have two Masakage Koishi's, a 180mm gyuto and 165mm nakiri. I began to thin the gyuto and figured I would make it a routine part of my sharpening, similar to the Murray Carter style where you thin a little each time you sharpen. Unfortunately I noticed almost immediately that the wedging became awful. Cuts seemed fine until it hit the shoulder and it would become extremely hard to continue the cut. I ended up continuing the thinning process and tried to remove the hollow grind, mainly focusing on bringing the shinogi up toward the spine/rounding the shoulders (the line isn't that clear due to the hammered finish). I'm at the point where I have nearly flattened the hollow grind, but still have some wedging/sticking issues. Feeling the knife shows that there are some thicker spots remaining along the shoulder that I can probably keep working on. I have been doing most of this with a Morihei Hishiboshi 500 stone.

I also began to thin the nakiri. After one thinning/sharpening session I could feel the extra pressure that I had with my gyuto (not to the same extent, but the exact same feeling and sticking point). Will this become an issue with the nakiri too until I completely flatten the bevel and round the shoulders? Also it looks like by raising the shinogi or rounding the shoulders I am trying to change the grind of the knife? Have I completely messed up here or will I get to a point where I achieve the smooth cuts as good as, or hopefully better than I had with the ootb knives?


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## M1k3 (Sep 30, 2020)

Sounds like you're making the bevels flat. Add some convexity to them.


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## 4wa1l (Sep 30, 2020)

In the case of the nakiri is this still true? The hollow still remains and I have barely touched it compared to the gyuto. Is there something about the roughness of the sandblasted ootb finish (I think) that would reduce sticking at the shoulder, or is it simply a function of geometry?


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## M1k3 (Sep 30, 2020)

The sandblasted finish can drag. Geometry plays a big role in cutting feel though. But a rough finish that doesn't allow food to slide is just about as bad. I'd try smoothing it out with some sandpaper, about 2k grit. You don't need to go crazy with the sanding. Just enough to smooth everything out. Autosol or similar polishing compound would probably work also.


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## McMan (Sep 30, 2020)

4wa1l said:


> I figured I'd add a post onto here rather than start a new thread, as I have a similar question.
> 
> I have two Masakage Koishi's, a 180mm gyuto and 165mm nakiri. I began to thin the gyuto and figured I would make it a routine part of my sharpening, similar to the Murray Carter style where you thin a little each time you sharpen. Unfortunately I noticed almost immediately that the wedging became awful. Cuts seemed fine until it hit the shoulder and it would become extremely hard to continue the cut. I ended up continuing the thinning process and tried to remove the hollow grind, mainly focusing on bringing the shinogi up toward the spine/rounding the shoulders (the line isn't that clear due to the hammered finish). I'm at the point where I have nearly flattened the hollow grind, but still have some wedging/sticking issues. Feeling the knife shows that there are some thicker spots remaining along the shoulder that I can probably keep working on. I have been doing most of this with a Morihei Hishiboshi 500 stone.
> 
> I also began to thin the nakiri. After one thinning/sharpening session I could feel the extra pressure that I had with my gyuto (not to the same extent, but the exact same feeling and sticking point). Will this become an issue with the nakiri too until I completely flatten the bevel and round the shoulders? Also it looks like by raising the shinogi or rounding the shoulders I am trying to change the grind of the knife? Have I completely messed up here or will I get to a point where I achieve the smooth cuts as good as, or hopefully better than I had with the ootb knives?


Few pics might help.


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## ModRQC (Oct 1, 2020)

Is the wedging occuring in all use of the length and with all produces? I would figure it rather present itself with taller and denser stuff, more towards the heel, in pure push cutting and/or with motion forward - meaning that the produce goes backward from say mid-blade to heel?


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## 4wa1l (Oct 1, 2020)

I'll get some photos tonight. Maybe someone can point out something obvious. 

Halving an onion was terrible. On a push cut down and with some forward motion, the edge cut cleanly but would get stuck once the shinogi entered the onion. Probably starting with the front third of the blade and sticking a little back from that. Not at the heel.

I guess I was trying to save myself from a big thinning session by doing it regularly, but it seems that I still have a heap of work to do. I would like to avoid the same issue with the Nakiri if possible.


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## Matus (Oct 1, 2020)

Whatever you do, do NOT remove the convex from the wide bevel if there is some. I used to have a Koishi nakiri, the grind was pretty much flat (plus some low spots, as expected). After working on it and adding some very gentle convex towards the edge, the knife became a much better cutter with less sticking-induced-friction. if your knife is just a little too thin behind the edge (I can't really imagine anything else), then just gently thin it there - no need to push up the shinogi - the knife is fairly thing already.


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## ModRQC (Oct 1, 2020)

4wa1l said:


> I'll get some photos tonight. Maybe someone can point out something obvious.
> 
> Halving an onion was terrible. On a push cut down and with some forward motion, the edge cut cleanly but would get stuck once the shinogi entered the onion. Probably starting with the front third of the blade and sticking a little back from that. Not at the heel.
> 
> I guess I was trying to save myself from a big thinning session by doing it regularly, but it seems that I still have a heap of work to do. I would like to avoid the same issue with the Nakiri if possible.



Try a pull push cut instead - have the knife work from mid blade to tip. Might take some adujstments to get it right but if your thinning is remotely sound it will be much better.

Your problem was best described by @M1k3 as suction instead of straight wedging. As you’ve flatten the secondary bevel in thinning you’ve made more of a V grind - hence suction and the shinogi will feel terrible in such cuts. Change your motion.

And seconding @Matus although he doesn’t need it, don’t do anything further before folks here sort you out.


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## ModRQC (Oct 1, 2020)

Edit: as per @M1k3 you can still try to smooth the scratch pattern with blending or finishing automotive sandpaper. Could help, will not deteriorate things further.


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## ma_sha1 (Oct 1, 2020)

McMan said:


> If the OP doesn't want to wedge carrots, then a laser would be a good place to start
> To my eye, the issue is not with this knife being thick behind the edge. The reason OP is having wedging seems to me to be an issue of grind/geometry. Wedging is a known side effect.
> 
> I'm not seeing much room to thin this knife.
> ...



Lots of contradicting opinions but I think the minority opinion from McMan is actually the correct one.

The edge & bevel portion is already very thin, wedging feel will only come if the carrot is taller than the shinogi. That’s because the shoulder, where bevel ends (shinogi) provide a sudden increase of thickness & resistance, it’ll basically split your carrot open by wedging/forcing it through using the shoulder from that point on.

No need to thin bevel or behind the edge, the area needs thinning is above the bevel, need to push up shinogi line by reduce the shoulder thickness. Measure the thickness of the shoulder at the shinogi line & compare to your Nakiri, I bet you’ll see that the shoulder is much thicker than the Nakiri’s.


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## 4wa1l (Oct 1, 2020)

Thanks for all the input so far!

It's hard to see in the photos but the right side hollow is almost fully removed so that the bevel is closer to flat. There is possibly an overgrind (I think that's what it's called) near the heel where the original finish is untouched.

The left side still has some hollow untouched sections remaining across more of the knife. I was thinking that I could work on this side more. I think it shows slightly in the choil shot too.

What surprised me was that the cutting seemed to be affected after the first time I tried to thin it. That was using only a Chosera 800, so I feel like there can't have been a huge amount of metal removed. There was definitely still significant hollow sections remaining in the middle of the bevel on both sides at that point.

Edit: I think I used the chosera 800 after the 500 stone last thinning to see if it made any difference.


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## ModRQC (Oct 3, 2020)

There’s nothing wrong with this. I like that choil shot. Your bevels are indeed into a pretty straight V grind though and you perhaps lost some of the effects from the original grinding. You took good care of your work however and I hope someone here will help you get it as you want.

Suction will happen when halving an onion with such bevels especially since the knife is much fatter at the shinogi. My Mabs wedged OOTB when doing so push cutting. It « sucks » now that I’ve thinned it. I could feel it was much more keen to go through it - but the onion slowed it to a crawl anyway. Pull cutting to halve ended the problem - working with the tapering of the blade lenghtwise instead of hoping from a V geometry to a rather thick shinogi to have any kind of alleviating effects for suction just because it was much thinner. It just went further before wedging is all. Mind you, bulk of my push cutting was amazingly elevated by the thinning too. Just not a geometry to push cut shinogi high dense and moist produces that adhere like crazy to the flat bevels. Talk about pull cutting these though...

Wouldn't do wrong to smooth out the scratch pattern as @M1k3 suggested initially, from what the pics show it's coarse enough to drag a lot.


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## M1k3 (Oct 3, 2020)

Here's some things to watch while you smooth the bevels.


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## JDC (Oct 18, 2020)

I feel that my recent observations on concave blades are worth reporting. 

I was doing some caliper measurements on my knives' geometries:
My best performing gyuto has a thin convex grind and a nail flexing edge, all numbers fall inside what @ian suggested before. 
All other knives measured a bit thicker than that, except one: my old, not in use Yu Kurosaki gyuto, which has a tall concave grind. 
I haven't used it for a long time since the performance was below average (still a decent knife, just not as good as other knives that I reground). 
It measured way thinner than any of my covex knives from say 3mm-10mm above the edge. 
So I gave it a quick thinning behind the edge, and boom, a super performer is born, which cuts even better than my best performing convex knife in terms of falling through produces. 
I only tested on carrots and celeries though. Food release was better than great, close to those S-grind knives. But I suspect it's gonna suck for produces that are a little softer, for example zucchinis and cucumbers. Will test and report back. 

Anyway, a geometry with ~3mm thin convex and concave grind above that is definitely something worth a try. Give it a shot, Takefu knife users


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## ModRQC (Oct 18, 2020)

In my experience the Kurosaki grind is hard to fault in technical use... but still wasn’t to my liking in terms of feel. It did suck a bit more with say potatoes, but really not something of a problem. Sold it because I found it very apt but rather boring in use. Also too light the one I had.


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## JDC (Oct 18, 2020)

ModRQC said:


> In my experience the Kurosaki grind is hard to fault in technical use... but still wasn’t to my liking in terms of feel. It did suck a bit more with say potatoes, but really not something of a problem. Sold it because I found it very apt but rather boring in use. Also too light the one I had.


Did you thin it? I found the original geometry boring too, quite normal and more suction on the bevels. It gets really fun after thinning.


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## ModRQC (Oct 18, 2020)

Nope sold it before it even could have a scratch. Didn’t lose a penny on that one.

And while I’ll never know regarding that one, in my experience so far thinning doesn’t change a knife’s feeling as much as enhancing what’s already there as a potential, and of course making it easier to initiate the cut/fall through. Then again at around 130-140g iirc the Kurosaki would never be one to fall through.


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## ModRQC (Oct 18, 2020)

Original choil - I kept all my pictures even of sold units.







It may not have been as thin as I brought my Mabs, and a couple of knives since, but not thick at all, and not to my senses calling for thinning of the bat. In fact, as far as 10mm behind the edge is concerned this one is an equal of my Ittetsu, and the latter sure doesn't need thinning yet, and sure is a tremendously fun knife to use.


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## JDC (Oct 18, 2020)

Can't see the thickness clearly right behind the edge, but sometimes that's where the magic happens. Very subtle changes may result in big difference in performance.


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## ModRQC (Oct 18, 2020)

Well I can see clearly enough for myself with that pic. At that level of zoom in, it's nowhere near thick, while not as thin as my Mabs now is, or my Yoshikane is OOTB. Fact is, what's different between the Kuro, the Ittetsu, the Mabs, or the Yoshi has nothing whatsoever to do with thickness behind the edge at those levels of thin. It's always to do with whole geometry, the feeling of cutting. Whatever ingredient shallow enough (small garlic clove for example) to be mostly concerned with thickness behind the edge but not geometry, just about feels the same for about any of my knife that's been thinned to some extent to match expected performance: like there's nothing there. YMMV.

I realize the importance of thinning, but am not of a school of thought that it has anything to do with anything else than cut initiation and ability to fall through when there's weight enough balanced forward enough. Another example is my Zwilling Diplôme/Deep Impact/Takayuki Kengata: they've been thinned, but are thicker behind the edge than aforementioned knives, about equal among themselves; yet their geometry as a whole is much thinner than the aformentionned. And these knives are righteous little performers that do especially good with hard dense ingredients and could halve an onion without wedging even when totally dull. I should know, since the Takayuki didn't even cut paper OOTB, and my Diplôme was used extensively for 4 months before being sharpened for the first time. I only thinned them recently - they never really needed it for my expectations of how they would work with stuff, but I had nothing better to work on, and of course they would need thinning in a near future anyhow so better set a thinner main bevel already.

Obviously, unless you thin to such extent as to transform geometry (way) above the edge. I'm not sure I would do that to a Kurosaki. Good chances there's not much people even around here that can NOT mess up with concave grind on the stones trying to thin higher than 10mm above the edge.


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## JDC (Oct 18, 2020)

No offense, but that’s a lot of words to reason against a simple observation: before thinning behind the edge, my Kurosaki Shizuku AS 240 was mediocre; after thinning it cuts better than a konosuke ys-m (which is at least on par with your Yoshikane) for dense vegetables.


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## ModRQC (Oct 19, 2020)

No offense taken, and I wasn't reasoning against, just stating what I've found for myself. As said YMMV and I'm just glad you could turn it into what you want. If a regular thinning behind the edge, I doubt it transforms how the knife feels as a whole is what I meant.

You seem offended though. I didn't judge of your Kurosaki, stated mine experience. How would you even know, on the other hand, that your Konosuke YS-M is "at least on par" with my Yoshi? Could be better, could be the same, but what it is is of no importance. I'd say that what you experience as a better feeling with your Kurosaki is your appreciation for the concave grind more than Yoshi/Kono YS-M grind (from choil shots they are very similar indeed), now that you've made it thin and sharp. Making my Kurosaki exacto-thin behind the edge wouldn't have changed a thing to how I felt about it, which is not to say neither that you shouldn't like it. YMMV.


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## JDC (Oct 19, 2020)

ModRQC said:


> No offense taken, and I wasn't reasoning against, just stating what I've found for myself. As said YMMV and I'm just glad you could turn it into what you want. If a regular thinning behind the edge, I doubt it transforms how the knife feels as a whole is what I meant.
> 
> You seem offended though. I didn't judge of your Kurosaki, stated mine experience. How would you even know, on the other hand, that your Konosuke YS-M is "at least on par" with my Yoshi? Could be better, could be the same, but what it is is of no importance. I'd say that what you experience as a better feeling with your Kurosaki is your appreciation for the concave grind more than Yoshi/Kono YS-M grind (from choil shots they are very similar indeed), now that you've made it thin and sharp. Making my Kurosaki exacto-thin behind the edge wouldn't have changed a thing to how I felt about it, which is not to say neither that you shouldn't like it. YMMV.



Yeah, YMMV, and your regular thinning may differ from mine too. Just want to encourage people to try this option if they are somewhat disappointed by the Takefu hollow grind. To me this is a significant improvement for not much effort.


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## ModRQC (Oct 19, 2020)

JDC said:


> Yeah, YMMV, and your regular thinning may differ from mine too. Just want to encourage people to try this option if they are somewhat disappointed by the Takefu hollow grind. To me this is a significant improvement for not much effort.



Yeah well anybody can say they thinned a knife and improved it. Once again, I was not judging the quality of your work (as you're implicitly judging mine), just stating my opinion. For someone who says he didn't use the knife for a good while after being disappointed, I could judge and say you didn't take the time to know the tool better, and after working on it, are you going to say you're disappointed? 

I may write longer posts, but I'm not just stating "I did good" and think people are going to believe me, and that I helped them progress. What I can do is give the detail as to how I approach the question and how I work. My regular thinning as you say isn't something preprogrammed. It's something I do according to each knife, as I feel for myself that they're calling for to maximize what is already there, after using them extensively enough.

In any case, I'm glad you are now content with the knife, the Kurosaki are well-made and appreciated by many, so it befits you to not abandon all hope and make it better. It's personally what I love the most about knives - how we get to learn from them being different, and how we can also improve them to suit our preferences.


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## JDC (Oct 19, 2020)

Sometimes more is less


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## 4wa1l (Oct 23, 2020)

Just an update with where I'm at right now. All the input has been very helpful so thank you! Looking back, I probably should've just kept sharpening the edge until it really started to thicken up, which sounds like it would be a while for a hollow ground knife. However, I figured that I had gone this far already so I might as well keep going. I'm well aware I've changed the geometry quite a bit now but I'm confident it will make the performance better in the end. Also I should've got an even coarser stone. Wasted too much time on this knife. Live and learn...

I continued with my morihei 500 until the bevels were both basically flat and attempted a sort of hamaguri convex. It's very minor and I left a small bit of the edge bevel untouched. The "shinogi" was also rounded a bit. I cleaned it up using the chosera 800 and then 3000. I also used a bit of the mud from the 3000 on a rag to try and clean up the soft stainless at the end. The finish definitely looks and feels a lot smoother. I think both the rough finish and flat areas played a role in the sticking so hopefully it should be much better now.

I haven't cut anything yet but am considering whether to just sharpen the small edge bevel or keep going with the thinning and aim for a zero grind style edge with microbevel (maintaining the hamaguri convexity). Any thoughts?

It's quite difficult to get a clear pic with the lighting, but I tried to get a representative section on each side. Finally managed a decent choil shot though.


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## JDC (Oct 23, 2020)

Looks a really neat job, congrats!

Depends your usage, you can either leave it like this or continue thinning. 

I'd say leave it if you cut meat frequently. If you chase the ultimate falling-through experience, do a zero-grind then put on a micro-bevel. The core steel will likely to wear faster than the cladding, so you'll have a natural convex anyway. My experience is you'll need extra care to flatten out the curvature near the edge for the best falling-through feel, it'll be less likely to crack carrots if you do so. However, you may choose to leave the curvature for better food release. Hope these helps!


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## 4wa1l (Oct 23, 2020)

I think I'll leave it and see how it performs with a sharpened edge (I'm a bit over thinning it for now). If it's still wedging I'll think about my options.

I found an old picture of the original finish. I actually much prefer the look now even though there is less contrast, more scratches and a few rough spots. The original finish looks too clinical in my eyes. Fingers crossed the performance is back to where it should be. I'll find out tonight.






Edit: I quickly cut up an onion, sweet potato and zucchini. The edge itself isn't that sharp, but it felt so much better through the onion. Of course there was pressure, but it didn't come to a hard stop like before and I could continue through the cut smoothly. A touch of cracking halving the sweet potato, but the cut was still clean. The smaller pieces were totally fine. Even food release is good, way better than my makoto gyuto. So overall stoked! Thanks everyone : )


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