# Shun Dual Core Knives, does the description even make sense?



## gic (Dec 29, 2014)

"The Shun Dual Core series features a Damascus blade made from two premium-quality, high-carbon stainless steels. 71 alternating micro-layers of high carbon, high chromium VG10 and VG2 stainless steels are roll-forged to produce a finer grain in the steel and to give it both strength and beauty. The laminated steel is then hot forged to create the herringbone pattern that allows the layers to alternate along the cutting edge. During normal use, the two steels will wear at different rates creating micro serrations along the edge so that the Dual Core's extremely sharp edge feels sharp longer. Etched laminations in the blade reduce drag, helping food release from the blade and gliding through each cut quickly and easily."

Can someone who knows more about knife making then I weigh in and tell me whether this even makes logical sense - could two steels layered actually give you super fine microserations and make the knife really toothy?

TIA


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## WildBoar (Dec 29, 2014)

Haha, I just read that at the Cutlery and More web site. Too funny.


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## TimoNieminen (Dec 29, 2014)

It's commonly said about folded steel edges. At one level it makes logical sense. But when I think about what will happen to an edge in use - rolling or micro-chipping - I don't know if it would help in practice.


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## cheflivengood (Dec 30, 2014)

gic said:


> "The Shun Dual Core series features a Damascus blade made from two premium-quality, high-carbon stainless steels. 71 alternating micro-layers of high carbon, high chromium VG10 and VG2 stainless steels are roll-forged to produce a finer grain in the steel and to give it both strength and beauty. The laminated steel is then hot forged to create the herringbone pattern that allows the layers to alternate along the cutting edge. During normal use, the two steels will wear at different rates creating micro serrations along the edge so that the Dual Core's extremely sharp edge feels sharp longer. Etched laminations in the blade reduce drag, helping food release from the blade and gliding through each cut quickly and easily."
> 
> Can someone who knows more about knife making then I weigh in and tell me whether this even makes logical sense - could two steels layered actually give you super fine microserations and make the knife really toothy?
> 
> TIA



the damascus is only ever cosmetic, it sandwiches the carbon or stainless steel that makes up the edge. at least that is 99% of good damascus. shun loves to BS


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## James (Dec 30, 2014)

cheflivengood said:


> the damascus is only ever cosmetic, it sandwiches the carbon or stainless steel that makes up the edge. at least that is 99% of damascus. shun loves to BS



These actually seem similar to the Echizen 1310 series, which is folded coreless damascus


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## Pensacola Tiger (Dec 30, 2014)

cheflivengood said:


> the damascus is only ever cosmetic, it sandwiches the carbon or stainless steel that makes up the edge. at least that is 99% of good damascus. shun loves to BS



Sorry, but you're wrong. 

Although the majority of damascus is cosmetic, as you say, some knives are forged from layers without a core, as is the case with the Shun dual core and the Echizen 1310 series, as James has said. This type of construction has been used by Devin Thomas and Del Ealy, to name two makers whose core less knives I have owned. I believe that Murray Carter sold some knives with this construction on his website, but they were not forged by him. 

Although the evidence is strictly anecdotal, the knives I have used do seem to hold a usable, toothy edge longer than you would expect. So Shun's claims are not "BS", at least in my experience. I'm tempted to buy one and see how it compares to my DT in that regard.

Knives of this construction are rare, so your misconception can be excused.

Rick


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## WildBoar (Dec 30, 2014)

The 'micro serrations' are what makes me laugh, since the write-up implies they are due to the different hardness of the two damascus layers -- the thicknesses of those striations are anything but micro. If anything, the difference in harness/ wear along the layers would turn the thing into a Cutco :biggrin:


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## cheflivengood (Dec 30, 2014)

Pensacola Tiger said:


> Knives of this construction are rare, so your misconception can be excused.
> 
> Rick



so like %1? irate1:


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## Pensacola Tiger (Dec 30, 2014)

cheflivengood said:


> so like %1? irate1:



I know of three that Devin has made, and Del has made about a half dozen, I think. Pierre Rodrigue has made a couple, and I think that Randy Haas has made several. But compared to the thousands of san mai damascus clad knives that have been produced, it is probably less than 1% - way less.


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## The Edge (Dec 30, 2014)

I have a knife with damascus to the edge that I got to make with Devin earlier this year, made from O1 and 15N20. While I prefer a freshly sharpened edge, on any knife, I would say there still is a slight benefit to the wear rates of the steels being different. Saying that, a dull knife is a dull knife, and even though I can go a slight bit more with the knife between sharpening, it is more due to the heat treatment than the micro serrations. I would still preach getting a knife with proper heat treatment first and foremost, rather than buying hype.


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## Pensacola Tiger (Dec 31, 2014)

The Edge said:


> I have a knife with damascus to the edge that I got to make with Devin earlier this year, made from O1 and 15N20. While I prefer a freshly sharpened edge, on any knife, I would say there still is a slight benefit to the wear rates of the steels being different. Saying that, a dull knife is a dull knife, and even though I can go a slight bit more with the knife between sharpening, it is more due to the heat treatment than the micro serrations. I would still preach getting a knife with proper heat treatment first and foremost, rather than buying hype.



With such a small sample (your knife and the one's I've handled), it's hard to say if it is the heat treatment or the micro serrations. Until someone has made a hands on report of a Shun Dual Core, determination of whether it is hype or not is impossible to determine. I think that the disdain that a large number of forum members have for Shun knives, whether deserved or undeserved, has colored the perceptions of anything Shun produces. 

Now, if I can convince my better half that I need a $300 knife for experimentation ....


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## The Edge (Dec 31, 2014)

Pensacola Tiger said:


> With such a small sample (your knife and the one's I've handled), it's hard to say if it is the heat treatment or the micro serrations. Until someone has made a hands on report of a Shun Dual Core, determination of whether it is hype or not is impossible to determine. I think that the disdain that a large number of forum members have for Shun knives, whether deserved or undeserved, has colored the perceptions of anything Shun produces.
> 
> Now, if I can convince my better half that I need a $300 knife for experimentation ....



I agree, though it bugs me that everything they sell tends to be the latest and greatest thing. Granted, that's marketing, and my experience is limited, but it's like the boy who cried wolf, if everything you sell is the greatest thing ever, then why switch it up constantly. Either way, my experience leads me to say that the micro serrations won't be at the level of sharpness most of us here strive for, and is aimed more towards those that don't want to sharpen their knives at all, or at least sparingly. Shun does make decent knives though, I just tend to look for things a bit more unique.


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## daveb (Dec 31, 2014)

Pensacola Tiger said:


> Now, if I can convince my better half that I need another $300 knife for experimentation ....



Fixed that for you Rick...:thumbsup:


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## panda (Dec 31, 2014)

shun = bose


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## Zwiefel (Dec 31, 2014)

panda said:


> shun = bose



This seems apt. (some will consider it an insult, some a compliment...and they will all be right.)


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## gic (Dec 31, 2014)

I wish we could get somebody like Devin or Pierre's opinion on what happened when they did this :- )


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## Lizzardborn (Dec 31, 2014)

Here are some layman opinions - the different rate of wear of steels wont help much - because edge degradation is mostly due to other types of stresses (you will have to cut a lot of potatoes, if suspended in the air with mechanical arm using the knife, before the edge is dull). Of course have two different materials with slightly different properties could help stabilize the edge.

Now - drag. Do you notice that in piping for dams - where the water flows there are barriers in the tubes - this is done so the water whirls in them and you have water/water friction instead of water metal for the bulk body of water. On micro level the edge should look like a staircase. Probably you can have similar effect.


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## cheflivengood (Dec 31, 2014)

Lizzardborn said:


> Now - drag. Do you notice that in piping for dams - where the water flows there are barriers in the tubes - this is done so the water whirls in them and you have water/water friction instead of water metal for the bulk body of water. On micro level the edge should look like a staircase. Probably you can have similar effect.



I never knew this Dam information


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## TB_London (Jan 1, 2015)

Look at some of Will C's threads on feather damascus. With this pattern the layers are turned perpendicular to the edge (whereas a lot of patterns have them parallel) so if there is a toothy effect it would be accentuated.

Damasteel is another industrially produced damascene steel used in knife making


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## Lefty (Jan 2, 2015)

Ok, I'm suddenly thinking I misunderstood this thread from the get go. Then again, I am up well before 5am, and my brain hurts. Anyways - if we're talking a 100% Damascus blade, on which the Damascus goes to the edge, then I'm with Rick; You can feel a difference in cutting, as well as the overall too thinness of the edge, depending on how you sharpen it. My only example of this now is a knife I have by Mike Davis. It's a scalpel of a 120mm petty, and let me tell you, you can feel the toothiness after a few sessions of food prep. It's not huge, but to weirdos, like us, who over-analyze everything about their knives, it is noticeable. If you go on the shaving forums, there are many who believe that you should absolutely not use a damascus straight razor, because they have a way of dragging more so tha their monosteel counterparts. 

The only other way I can attempt to describe it is: Has anyone here worked with Birdseye maple? If you sand it with a hard block, at coarse grit, you can feel the different levels, yet when you sand with a hard block, at a fine grit, the feel of the wood is virtually the same across the piece. However, if you then take a soft sanding sponge (even superfine), and sand the surface, you will now feel peaks and valleys due to the different hardness/wear resistance of the wood, because of the figuring. Now, think of the sanding sponge as the food being cut by a Damascus knife, and it sort of illustrates what Shun is describing. I hope.


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## rick alen (Jan 2, 2015)

This maker does a real Damascus with s90v and s35vn.
http://cosmoknives.com/its-all-about-the-steel/


Rick


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## gic (Jan 2, 2015)

Anyone know anything about this guys knives??


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## Matus (Jan 2, 2015)

Dual core is old news - today one expects at least quad core


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## CoqaVin (Jan 2, 2015)

are we talking about PC's here Matus? :justkidding:


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## Zwiefel (Jan 2, 2015)

Matus said:


> Dual core is old news - today one expects at least quad core



And lots and lots of RAM!


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## CoqaVin (Jan 2, 2015)

Forget quad I WANT OCTA!


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## Matus (Jan 3, 2015)

CoqaVin said:


> Forget quad I WANT OCTA!



And forged by droid-san


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## psfred (Jan 3, 2015)

My personal feeling is that if you want microserrations you can always buy Cutco and let them sharpen them once in a while.

I don't see much advantage of having half the edge of the knife dull mch of the time. Toothy edges are easy enough to produce on a set of stones if you want one, without the expense of "damascus" steel, and there won't be the differential sharpening and dulling (since the steels with sharpen differently too!).

My opinion of Shun is that they use gimicky advertising and gaudy designs to sell run of the mill knives to people who don't know better and tend to confuse price with quality. Other than being excessively chippy in some cases, they aren't bad knives, but you can get better and more usable profiles with better steel cheaper, and knives are, for me, about food prep, not impressing rubes.

I'm certainly not going to spend a pile of money on one to try it out!

Peter


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## CoqaVin (Jan 3, 2015)

yea but fred don't you know Shun is the best?:wink:


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## salmonkiller (Jan 3, 2015)

Would the new Shun knives be similar to Saji Core-Less Custom Damascus Series?





The advanced Clad technology by Takefu Special Steel Company made it possible to forge welding two different Hagane steels of the VG-10 and VG-2.


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## salmonkiller (Jan 3, 2015)

Takefu Special Steel Co.,Ltd. Interesting read and information.


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## Pensacola Tiger (Jan 3, 2015)

psfred said:


> My personal feeling is that if you want microserrations you can always buy Cutco and let them sharpen them once in a while.



That's pretty funny, Peter. Comparing a Devin Thomas or Del Ealy blade to Cutco.

Rick


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## Lefty (Jan 3, 2015)

I think Shun tested this product heavily, noticed that it retains a toothy edge for a long time, and their spies (hey, spies. What's up?) saw that we occasionally discuss the advantages of a toothy blade, and they ran with it, in terms of marketing. They make good knives, but aren't on cool knives list, so people bash them. Ae they expensive for what they are? Maybe, but I don't believe excessively so, when you compare to a few makers who really couldn't make a piece to rival Shun, and charge even more.


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## panda (Jan 3, 2015)

Irregular edge dulling/sharpening would be mightily annoying!


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## salmonkiller (Jan 3, 2015)

Has anyone actually used/sharpened this knife first hand and can comment on how it feels, performs and why they like of dislike it?Shun is not the only maker to produce dual core construction knives.Does anyone have experience using dual core knives?
Best,
salmonkiller


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## rami_m (Jan 3, 2015)

I think Rick has. The information is higher up this thread. Or maybe the other one


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## Lefty (Jan 3, 2015)

It would still sharpen the same. We're talking MICRO.


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## Pensacola Tiger (Jan 3, 2015)

salmonkiller said:


> Has anyone actually used/sharpened this knife first hand and can comment on how it feels, performs and why they like of dislike it?Shun is not the only maker to produce dual core construction knives.Does anyone have experience using dual core knives?
> Best,
> salmonkiller





rami_m said:


> I think Rick has. The information is higher up this thread. Or maybe the other one



My experience is with knives of the same construction, three by Devin Thomas and one by Del Ealy. I'm considering picking up the 8" Shun Dual Core K-tipped gyuto. If I do, I'll be glad to review it.

Rick


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## salmonkiller (Jan 3, 2015)

Some information from Carter Cutlery RE: dual core knives I believe he had previously imported knives that were dual core.This type of construction seems to be pretty rare to date.I ponder why everyone tends to dog pile Shun for bringing to market a line using a steel construction that most of us have never tried, used, and experienced.I would like to give it a try in my kitchen even though neither VG10 or VG2 would be near the top of my list of preferred steels.Time will tell for those willing to cough up the dough.....


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## salmonkiller (Jan 3, 2015)

Thank you Rick..I look forward to your review if you pick one up..
Best,
salmonkiller


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## psfred (Jan 3, 2015)

Well, Cutco does drone on and on about the advantages of microserrations, after all. 

Someone besides me will eventually buy one and test it to see if there is anything to it. Probably the "miracle knife" de jour though -- I've heard the same things on other fora with an equal dearth of hands-on experience.

Peter


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## salmonkiller (Jan 3, 2015)

I wouldn't believe anything Vector Marketing says. Micro serrations are easy just sharpen to a course edge.Seems like it would be a stretch in my mind to compare some college kid pyramid scheme marketing knife in 440A to a coreless damacus steel that has been used by some very reputable knife makers.For some people Cutco products work perfectly fine and the same goes for Shun.Not everyone is a knifenut.That is why I bear the question if anyone has experience with the coreless steel.I am trying to put and hype and marketing aside and asked for an objective opinion about Shuns dual core line.
best,
salmonkiller


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## leiatlarge (Jan 3, 2015)

All joking aside, this sort of steel is pretty interesting, would love to hear an unbiased review once it's out. My first "good" knife was a Shun and even though I'm more selective with my knife these days, that dual-core Kiritsuke 8" looks great. Any guesses on the HRC of these knives?


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## rick alen (Jan 4, 2015)

30 years ago I recall folded steel was all the rage. The custom makers at the time claimed it got sharper and held an edge better than their mono-steel stuff. Their reasoning was that the high-carbon got glass hard, while the low carbon "backing" layers provided toughness.

At the same time I had read articles saying that antique wootz (the only crucible-grade steel prior to the 1700's) blades were superior to their folded-steel Japanese counterparts. So there is conflicting info here right from the early stages of folded steel in the US. And I'd have to say that the article on wootz has to be less biased as compared to the custom makers hype.

If regular high-carbon/low-carbon steel is superior to monosteel, why is it that virtually no high-end Japanese smiths use it anymore in their knives?

There could be some advantage to using 2 CPM alloys in a folded arrangement, but certainly it does not look that way for ordinary steels.

I'd have to say that Cosmos Design's use of s90v and s35vn is more interesting in respect to what Kai/Shun is doing.


Rick


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## mano (Jan 4, 2015)

The Edge said:


> It bugs me that everything they sell tends to be the latest and greatest thing... if everything you sell is the greatest thing ever, then why switch it up constantly... I just tend to look for things a bit more unique.



This struck me as funny, considering the vast majority of cooks use only one primary knife, while most of us here "switch it up constantly" with lots of expensive 240 gyuto's that -for practical purposes- are not all that unique. Shun is selling items that last years, usually a lifetime. So, yeah, they have to come up with new and better to attract new customers.


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## LKH9 (Jan 5, 2015)

salmonkiller said:


> I wouldn't believe anything Vector Marketing says. Micro serrations are easy just sharpen to a course edge.Seems like it would be a stretch in my mind to compare some college kid pyramid scheme marketing knife in 440A to a coreless damacus steel that has been used by some very reputable knife makers.For some people Cutco products work perfectly fine and the same goes for Shun.Not everyone is a knifenut.That is why I bear the question if anyone has experience with the coreless steel.I am trying to put and hype and marketing aside and asked for an objective opinion about Shuns dual core line.
> best,
> salmonkiller



If I've not mistaken, it because the dual-steel sharpens itself when it's used, due to the softer steel wearing out faster. Like the birdeye maple wood someone mentionef here. Theoritically it's different from a coarse edge from a coarse stone, that will dull just as fast.


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## TimoNieminen (Jan 5, 2015)

rick alen said:


> At the same time I had read articles saying that antique wootz (the only crucible-grade steel prior to the 1700's) blades were superior to their folded-steel Japanese counterparts. So there is conflicting info here right from the early stages of folded steel in the US. And I'd have to say that the article on wootz has to be less biased as compared to the custom makers hype.



Wootz is ultra-high carbon (1-2% carbon), typically well over 1% (before forging; might drop close to 1% during forging).

The Japanese sword is (usually) a laminated construction, but the edge and the cladding are individually monosteels - no "dual core". The individual parts are folded, but that's the usual treatment for bloomery steel which is smelted in the solid state and full of slag and inhomogeneous. Fold it to drive out slag and homogenise. Typical carbon content for the edge steel is about 0.7%.


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## rick alen (Jan 5, 2015)

The folded Japanese swords did not necessarily have cladding, though that would have made construction much easier. As I understand the folded billets were constructed so that when the sword blank was pounded out the layers would be .001-2" thick. Making them any thinner would cause carbon migration from the high-carbon layers, any thicker and the sword wouldn't take a good edge. Once the blank is formed there is much metal removal to get it to shape.

You make a good point Tim, given the carbon content of one to the other we are not really comparing apples to apples in terms of what we can possibly be done with modern steels.


Rick


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## Zwiefel (Jan 5, 2015)

Thanks for the posts Rick/TimoNieminen! It got me to looking around for info on Katana construction, and I found this on Wikipedia:










I didn't realize either the breadth of construction methods or the complexity of some of them. 




rick alen said:


> The folded Japanese swords did not necessarily have cladding, though that would have made construction much easier. As I understand the folded billets were constructed so that when the sword blank was pounded out the layers would be .001-2" thick. Making them any thinner would cause carbon migration from the high-carbon layers, any thicker and the sword wouldn't take a good edge. Once the blank is formed there is much metal removal to get it to shape.
> 
> You make a good point Tim, given the carbon content of one to the other we are not really comparing apples to apples in terms of what we can possibly be done with modern steels.
> 
> ...


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## LKH9 (Jan 5, 2015)

They are using this exact same method to make kitchen knives and scissors after the outlaw of samurai class.


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## TimoNieminen (Jan 6, 2015)

rick alen said:


> The folded Japanese swords did not necessarily have cladding, though that would have made construction much easier. As I understand the folded billets were constructed so that when the sword blank was pounded out the layers would be .001-2" thick. Making them any thinner would cause carbon migration from the high-carbon layers, any thicker and the sword wouldn't take a good edge. Once the blank is formed there is much metal removal to get it to shape.



AFAIK, the folded layers are always of the same steel in traditional Medieval and later Japanese swords. The folding is only to get rid of slag in the bloomery steel, and to homogenize the carbon content. Too few folds, and not clean enough or homogeneous enough. Too many, and you lose too much carbon in the forging. The point is that they didn't want high-carbon and low-carbon layers in the folded parts - that's what the laminated construction is for. This is a difference between Japanese sword making and early Medieval European pattern-welded sword making, which did use high- and low-carbon layers.

The unlaminated blades (generally only mid-16th century and later) are often unfolded - these are usually made from imported steel, which was often Indian crucible steel and much cleaner and more homogeneous to start with. Common enough to see unlaminated differentially hardened Chinese knives (good swords were usually sanmei) with no evidence of folding - that's with traditional steel usually mmade by decarburising cast iron, so starts clean.

Not that much metal removal for a katana, not enough to call it stock removal. Forged to shape, with metal removed in the polish/sharpening. "To shape" in this case means to a straight blade; the curve comes from the quenching. If you haven't seen it, you might like video of this: [video=youtube;HOTKVLZlM8Q]https://www.youtube.com/watch?v=HOTKVLZlM8Q[/video]


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## rick alen (Jan 6, 2015)

Sorry, wouldn't be the first time I was thoroughly misinformed. But I look at it this way, if I didn't show my ignorance in places like this I would never know different. Thanks for the correction.


Rick


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## Lizzardborn (Jan 6, 2015)

LKH9 said:


> They are using this exact same method to make kitchen knives and scissors after the outlaw of samurai class.



The only difference between katana and yanagiba is that in the first case the protein is tougher and not on a cutting board.


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## Zwiefel (Jan 6, 2015)

Lizzardborn said:


> The only difference between katana and yanagiba is that in the first case the protein is tougher and not on a cutting board.



Well, in Japanese cutlery construction in general, the core steel is the Hagane, and the cladding is the jigane....whereas the swords are the opposite. However, the Hagane is used for the cutting edge in both.


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## LKH9 (Jan 6, 2015)

> The only difference between katana and yanagiba is that in the first case the protein is tougher and not on a cutting board.


The grind is different, a katana's grind is very thick, like an oversized axe so that it won't chip when hacking at bones. Yanagiba lazers thru food but will chip easily due to the thin edge.



> the curve comes from the quenching


This is the thing that makes yanagibas bend after being quenched.

A good read for those who like swords. http://chineseswords.freewebspace.com/contact.html


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