Rambling thoughts on gyuto profiles

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Kippington

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I've been in a few conversations with people about gyuto profiles, and I've come to the conclusion that I envisage this topic slightly differently from most others. Perhaps my way of thinking is more efficient, or maybe not. I'd like to find out so please feel free to chime in with your thoughts.

In any conversation about profiles, the major measurements we start with are the length of the cutting edge and the height of the knife at the heel. With the tip of the gyuto being a point, we can use these measurements to draw a triangle.


Easy enough, but where do we go from here? The next point people like to bring up is the height of the tip relative to the heel, kind of like this:


But in the case of this triangle, how can we tell what angle to hold the knife in order to make this reading? You might think the answer is straight forward - to hold the cutting edge down before taking this measurement (like the one below, on the left), but even then there's a problem with the spine height, which I'll get to later.


So instead, I believe the next most important aspect after length is the combination of flat-spot and belly curve. These are the defining aspects on how the knife performs in either a rock or a chop - you don't even need to see the rest of the knife to get an idea of how it moves on the board.


I could give a more in-depth explanation on the flat-spot and belly curve, but that would go too far off this topic, and I think that most people here understand it well enough. If not, let me know.

Now that we have the cutting edge set, if we lay the flat spot down against the board the next important measurement should be the angle of the spine (as well as the handle, if the two are parallel) in relation to the board. The distance of your cutting surface to your elbow height is a major determining factor for this angle. Also, we actually need less heel height to get the same amount of knuckle clearance if the handle angle is steeper.


I'd like to point out that even though the two above have exactly the same flat-spot and belly curve (meaning they would behave quite similarly), they appear totally different if described by tip height alone.
You can hopefully see how I think it's wrong to describe one of these as "low tip" compared to the other: it isn't technically true. It's also a good time to bring up what I mentioned earlier - holding the flat-spot down doesn't change the illusion that one tip appears lower than the other.

Next I think of the choil shape - an important factor for comfort and safety. This probably should be higher up on the list in importance but it's easier to slot it in here.


Then the least important aspect and final thing to be modified would be how the spine curves into the tip. The Masashi gyuto cops a lot of flack for how they do this, but I honestly think it hardly matters.


So in a nutshell, it can be really confusing to talk about the profile of a gyuto in terms of tip height, as its relative position can be a bit of an illusion and relies on a couple of other more-important factors.
There are a few other points, but before I go into them - What do you guys think? Does this make sense, or have I lost the plot... o_O
 
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Mute-on

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Makes perfect sense. Having the spine more parallel to the edge always seemed more natural to me as it keeps the back of the handle a little lower, and closer to the board.

However, some upwards sweep of the handle (and therefore a lower appearing tip) is also necessary to help with glide. Naturally this will feel different to each user depending on their height, the work surface height, and personal preferences.

As far as choil shape, I vastly prefer a wider neck (emoto?) and a larger choil radius like on a Kato. However, unless the neck is very narrow, I probably wouldn’t notice after a few minutes.

Of course this might all just be a load of self indulgent BS and I’m deluding myself. Oh well ...

Cheers

J :)
 

RDalman

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yea good writeup! Slim tip a la KS can have some suji-like features and help it with release also. And there's the possibility of using a little recurve to the spine to mess with the profile and handling angle even more.
 

ecchef

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I love this type of thread. These topics really bring about the best discussions.
Good point about spine recurve, Robin. I’ve been using a Sakai Takayuki Grand Chef lately and, although I don’t know the mechanics behind it, the slight spine recurve does seem ro make a difference.
 

Barmoley

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Great thread and write up. Matus should chime in, him and I were discussing this subject a few years back. It seems when people discuss blade height at the heel and knuckle clearance, what we really deal with is the angle of the handle vs the edge and also the height of the elbow over the cutting surface. So you could have a knife that is relatively low at the heel, but still gives a lot of clearance and is still comfortable plus the benefits of less drag, etc.

It also seems that some blade shapes are more visually appealing to most people. For example symmetrical, pointy shapes such as KS and Shig just look good even though the shape of the spine doesn't really affect performance as much as the other attributes of the profile.
 

HRC_64

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Great post ...

On tip height, the "angle of attack" of the handle needs to be considered as you mention to me the concept of tip height is straigt forward...

1) the top of the blade (spine/handle) is paralell to the cutting surface, and
2) choil is at 90* ortogonal spine/handle and to cutting surface



normally its pretty easy to sort it out and possible to evaluate most comparisons
ie,...if you use photoshop, no problems...but sometimes maybe its a personal view,

(and sometimes maybe the maker puts the convex/grind indepently of either)
 
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Interapid101

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I love this type of thread. These topics really bring about the best discussions.
Good point about spine recurve, Robin. I’ve been using a Sakai Takayuki Grand Chef lately and, although I don’t know the mechanics behind it, the slight spine recurve does seem ro make a difference.
Curious, how does it feel different?
 

HRC_64

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Perhaps its worthwhile to think of the gind like an air-foil (cross section)
and then think of the chord which has the greatest width to the air-foil centerlind,
where that is vs the edge or spine is in part a function of where it is absolutely,
but aslo proportionally ...ie, "in the middle" or "1/3 from the top" etc, so
if the shape of the spine, and/or if the spine is not flat, the chord-
moves relatively to the spine along the cutting edge....i think.
Or maybe I'm crazy. :)
 

valgard

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For me the angle of the cutting edge (longer section to the back) with respect to the handle/spine is a MAJOR factor, as well the angle between the handle and the board to be able to put the tip down. Those two determine a lot of what's comfortable for me.
 

JaVa

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Curious, how does it feel different?
IME It changes the balance of the blade significantly by adding more weight to the knife, making it more blade heavy as the added steel is right at the tip. The added surface area at the tip will make food release a bit worse and any task that requires puncturing will suffer too (like removing silver skin from meat) because the stubbier tip will have more resistance and the added drag doesn't help either.

Though with good taper and a thin tip some of those problems can be avoided to a degree.




Personally I like a semi pointy tip, long flat spot (like half the edge length) that progresses to a naturally rolling tip that's marginally lowered. I like the handle, spine and flat spot to be all in the same angle and paralell to the cutting surface.

Perfect height is for me is about 50mm. As I'm not that tall a taller blade and/or a handle that's curved up a bit will force my wrist in a slightly awkward position.

Edit.
Also a thinner neck feels better as it's more nimble for me. Though a tall neck feels more secure and powerful, but at the same time too cumbersome and slow.
 
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McMan

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As always, cool points and super helpful images, Kip!
I think the different amount of meat above the tip also raises questions about weight and balance-point. Tip shape is (or at least could be) a factor here, no?…

Your tale of two tips is interesting, since both examples are pretty well known gyuto shapes…
(L) Left example = more weight above the tip (due to tip shape) but also behind the tip (since the spine is higher for longer and closer to parallel to the edge for longer)
(R) Right example = less weight above and behind the tip (due to a pointier tip and a more/sooner inclined spine).

Of course, balance-point and weight are affected by several other factors (distal taper overall, how quick/severe the distal taper is, thickness at the neck, grind, etc.). But tip shape--and how it relates to spine slope--would seem to be one among multiple other factors. How impactful it is compared to other factors would be interesting to chase down…

Assuming the two knives above also have the same grind, distal taper, and all that jazz, what we'd be left with is Left is heavier and more balance-forward, right is lighter and balance closer to the handle. Right?
 

merlijny2k

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There is imo another factor where tip shape matters. Since you can only go so thin at the spine before the tip becomes too fragile, the left knife can have the primary grind bevel at a steeper angle in the tip area, therefore the tip may even outperform the tip of the right shape for some tasks like carrot cutting for example. I see this between my Kanso (left shape) and my sabatier (right shape).
 

merlijny2k

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I really enjoyed your writeup. Been mulling at the subject myself for a long time.

There are many productive thoughts in it but there is one thing about your system that I find less elegant. You start with a triangle but you eventually ditch... basically everything except the heel and the neck point. Makes me think you have a good system but could do with a more elegant start. I will try to do some drawings (and get them in here....) tomorrow. This discussion is too good not to join.
 

LucasFur

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Chiming in ...

(L) Left example = Takeda -- Large Santoku hybrid
(R) Right example = Masamoto KS -- short Sujihiki hybrid.


One thing I will say, is that I like when the handle is angled up ... towards me ... Like the left Photo. *But* Cutting board height makes a massive difference in what is preferable. (For me)
 

HRC_64

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Angle of attack for handle impacts also

hand clearance
push vs pull cut

etc
 

HRC_64

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Here is a push-cutter example
note the high tip, flat profile blade.

Guillotine à Saucisson


Whereas a standard suji has also has a flat profile,
but combined with a low tip heigh, low heel height,
and relatively flat angle of attack.
 

Kippington

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Some really good points here.

LucasFur, JaVa and merlijny2k rightly mention the influence the size of the tip has on balancing point, food release and thinness of the grind... I'd like to add flexibility/rigidity to that list.
I had the shape of the tip positioned near the end of my list of importance because of how dependent it is on other factors (spine and belly). But maybe I should reconsider my priorities.

Dalman and ecchef mentioned the recurve (sori) blade, so here's an image of one... and why not throw a K-tip in there for good measure! All of these have exactly the same belly and flat-spot.


There are many productive thoughts in it but there is one thing about your system that I find less elegant. You start with a triangle but you eventually ditch... basically everything except the heel and the neck point. Makes me think you have a good system but could do with a more elegant start. I will try to do some drawings (and get them in here....) tomorrow. This discussion is too good not to join.
Please do! Tell me more, I'd love to hear what you have to say - and anyone else for that matter. I put this up as a discussion for debate!

I'm glad some of you are talking about your preferences on the spine/handle angle of attack. The topic doesn't come up often in these kinds of conversations and I figured it was something people didn't really think about. Very happy to be wrong.
Personally I like a semi pointy tip, long flat spot (like half the edge length) that progresses to a naturally rolling tip that's marginally lowered. I like the handle, spine and flat spot to be all in the same angle and paralell to the cutting surface.
Perfect height is for me is about 50mm. As I'm not that tall a taller blade and/or a handle that's curved up a bit will force my wrist in a slightly awkward position.
Also a thinner neck feels better as it's more nimble for me. Though a tall neck feels more secure and powerful, but at the same time too cumbersome and slow.
Everything you say here makes me think you have a really high cutting surface, like you could knock your elbow on it walking past. Would that be right?
Either way, the closest knife I've used to fitting your description is a Shig 240mm, and ohmygosh it was fun to use on a high cutting board! :D
 
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refcast

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To add more about tips:

A high tip angle allows me to cut with a higher angle. It's like the difference between the force when I poke myself with a straight finger (where the tip would be 90 degrees) versus with my fingerpad (a nakiri or kakugata usuba with no tip curve). I feel it gives more cutting force per user force input. This is obvious to me when peeling in hand.

I prefer a pointy tip versus a super thin flat tip if I had to pick, but I enjoy and can use both.

Lastly, the amount of downward curve from the top of the knife makes the knife more agile but less workhorsey. We can start angling down from the handle, which is good for heavier or taller knives to feel more nimble, or we can start near the tip to keep the workhorse feeling for thinner knives. Of course there is a trade-off in weight, and there are so many configurations that can be appropriate.

I like to think of the basic knife shape as going from nakiri to kamagata usuba to various tips and angles and spines.

Spine recurves make me want to hatchet-kind of chop. I like to imagine that the curve has a lowestmost point and I kind of swing from heel to that lowest point.

Lastly, sometimes the steel can be a bit undamped, which can be problematic when the tips are thin. I find some steel can feel "denser" but really they just are bit more damped when springing back from the super small left-right displacements that happen in cutting. I still like thin tips.
 

Kippington

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Lastly, sometimes the steel can be a bit undamped, which can be problematic when the tips are thin. I find some steel can feel "denser" but really they just are bit more damped when springing back from the super small left-right displacements that happen in cutting. I still like thin tips.
There's definitely a sweet spot for springiness. I often hear complaints about blades being too flexible, but I think the reverse (a clunky thick tip) tends to be put up with more often.
__________________

Okay, here is something that hasn't been mentioned yet - I like to call it "the KS effect".
It turns out that the choil (or better yet, the emoto) - with all other things being equal - has a significant effect on how the overall knife behaves and can actually nullify a precise measurement of the heel height.
Take a look at this example:

These two profiles are identical in terms of the properties we've talked about so far. Blade shape, flat spot, the handle/spine angle relative to the board... all of these essentially duplicated. If we were to take each one and measure the height of the knife at the heel, the numbers would come out exactly the same. However it wouldn't give a good indication of how tall each knife feels on the board, as the shape of the emoto has caused the one on the left to be a "shorter" knife, while the one on the right is "taller". It's a difference of only a few millimeters, but it's enough to feel during use.

I first noticed this while looking closely at the Masamoto KS to work out why the blade looks so thin and slender, and I soon came to realize that their style of emoto raises the handle off the spine and gives them more space to work with. Other styles of emoto can cause handles to rest closer to the board, despite what an equivalent heel measurement might indicate.
Compare the following image to the one at the top of the thread - Could it be considered a KS clone? :p
 
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JaVa

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Everything you say here makes me think you have a really high cutting surface, like you could knock your elbow on it walking past. Would that be right?
Either way, the closest knife I've used to fitting your description is a Shig 240mm, and ohmygosh it was fun to use on a high cutting board! :D
Well, a Shig does have just about the perfect profile for me, that's very true. Wakui Kasumi (EE version!!!) is another one, as the profile is VERY close to Shigs profile, but the Wakui is thinner behind the edge and it has even slightly better cutting performance, but less food release.

Great point about work space height, but my cutting surface at work and at home is the normal height, but as I'm 170cm tall, the effect would be about the same. I just went to measure and there's about 7,5cm clearance between my elbow and the cutting surface.

Another reason I don't like too much belly and a high tip is because I'll knick my middle fingers knuckle easier with a knife like that. When I raise the blade and rest it on my finger, due to my height the tip will point just a tad bit too high and if I'm not paying attention, when I slice the blade backwards it can sometimes knick my knuckle ever so slightly. A taller blade will make the matter even more difficult as I need to lift it higher and as a consequence the tip will be angled higher still. So again it's the same effect as if the counter top would be too high.

Not a big deal at home, but at work when you need to plough through 20 to 30 kg of veg as fast as you can, it makes a world of difference for me. Also that's when a long flat spot shines for efficiency and more precise cutting.
 

JaVa

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There's definitely a sweet spot for springiness. I often hear complaints about blades being too flexible, but I think the reverse - a clunky thick tip - is put up with more often.
__________________

Okay, here is something we haven't mentioned yet - I like to call it "the KS effect".
It turns out that - all other things being equal - the choil (or better yet, the emoto) has a large effect on how the overall knife behaves, and can actually nullify a precise millimeter measurement of the height at the heel.
Take a look at this picture:

All of the properties we've talked about so far - blade shape, flat spot, handle/spine angle - they are all identical for these two blades. If we were to measure the heel height of each one, the numbers would come out exactly the same, yet it wouldn't be a good indication of how tall each knife feels on the board. The shape of the emoto has caused the one on the left to be a shorter knife, while the one on the right is "taller".

I noticed this when looking closely at the Masamoto KS to work out why the blade looks so thin and slender. I've come to the conclusion that their style of emoto gives them more room to work with, and that some other emoto-styled knives sit closer to the board than a heel measurement might indicate.
Those would be some of the reasons I like a thinner neck much more and why it feels so much more nimble.
 

refcast

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Thanks for pointing out blade height differences caused by neck thickness.

I didn't mention this earlier because we were focusing on the profile only -- but the way I use a knife changes when we consider neck thickness and the handle thickness in knuckle clearance.

I could describe it as how far the edge is away from the central axis of the handle, which tells me how nimble a blade is. I can idealize the most nimble shape of a knife as a stick. If I add weight further away from the stick, it requires a bit more effort for me to rotate the knife for motions like cutting horizontally, as well as move around. So a shorter knife emphasizes nimbleness in movement. But I gain a big advantage in being able to apply less user input force for a similar cutting output. This helps a ton. So I feel I gain nimbleness in cutting action.

We would add weight in the KS picture with the overlay if we added machi. This would add weight and make the knife heavier. It would change the weight distribution though, and may make it feel more nimble or predictable in some ways.

I also am not considering angle of handle attachment, and left-right displacement of the handle from center, which can do stuff, too, to feelings of nimbleness/instability versus feeling more locked in.
 

panda

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just combine edge profile of a KS with spine profile of Mizuno = perfect blade shape
 

HRC_64

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Compare the following image to the one at the top of the thread - Could it be considered a KS clone? :p


That second outline is a "sakai 270" ;)

Only half-joking, as the 250 KS is an exact 270mm measured at the machi/insertion point. KS has not only a very narrow emoto, but its also longer than normal.

From another/design point of view, this puts the handle a bit further
back than normal and plays into the overall balance of the knife,
the handle acts like its a bit lever this way, and seems more nimble

I know the KS gets slagged on alot her at KKF but the overall design has alot going on
and all of these factors are what makes is 'work' a bit better
 
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Keith Sinclair

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Good thread
Head Gardemanger years liked the thinner tip of the Masamoto for decorative food work and slicing duties. For knocking out lots of banquet prep. like good flat & taller tip for forward push & chopping. One can not live with one style of gyuto alone;).
 

Kozuka

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Chiming in ...
*But* Cutting board height makes a massive difference in what is preferable. (For me)
Interesting point, never thought of the actual work height in relation to the knife format / geometry.

Great thread alltogether, thanks for sharing and discussing guys!
 
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