Why Kamakura = best swords ever??

[Alex A]

How many times have we seen it in this thread with regards quotes about differences in carbon content=hada visible (From expert smiths that make swords)

 

Jacques shows quotes from the craft of the Japanese sword plus videos

 

Videos from expert smiths saying differences in carbon content = contrast.

 

Wikipedia

 

Starts off from 2 different materials , just because its hammered and folded into1 dont mean it was made from 1

 

Il stick with available info, cheers

 

Will look in, hopefully move on as this has gone sideways again lol

 

EXPLAIN WHY KAMAKURA IS BEST, YEH RIGHT, GOOD LUCK WITH THAT 

[Jussi Ekholm]

Here is also quite interesting article by Usagiya. I believe Keiun Naohiro made two kobuse constructed blades from same steel block (using this as the outer jacket). Aiming for Norishige like appearance.

 

http://www.ksky.ne.jp/~sumie99/Norishigeappearance.html

 

You can see the pictures in the link above, I will just quote his thoughts on subject.

 

Quote

Consideration
The steel layers must be the same on both blades, because they are sisters those are made from the one steel block. But the appearance of the steel are quite different, as no one may not find that they are the same steel. The tachi has a large layer pattern with visible jinie (steel particles), even in the hamon area. On the other hand, we can't recognize such a large layer pattern on the wakizashi. The steel layer is not visible, it looks full of tight jinie. The difference of the appearance is a difference of steel grain. It is not a difference of layer pattern. The grain of steel particles is effected by tempering work.

 

Lots of very interesting articles at Usagiya.

[mas4t0]

This video might help people to visualise grain size and some other aspects of heat treat (it's very beginner friendly):

 

 

[Toryu2020]

Jean - enjoying your comments and I like the points you have made.

 

I would posit that your example of the use of namban tetsu is not a good analogy. We were taught that the amount of namban tetsu used in the famous Yasutsugu swords (for example) was miniscule - just enough to say that he used some as it was a novelty and it added nothing to the overall product. His jigane I think most would see as quite clean and consistent so not a deliberate "damascene" hada.

 

I think Yakumo-gitae or the Shin Ju-go-mai of Omura Kaboku would be better examples of later smiths using mixed metals for effect.

 

Alex - the short answer to the question is "You need a full education in nihonto to appreciate why Kamakura is the best." ( I was told the same thing when I started btw) The long answer is below;

 

Sugata - the shapes produced in this time period are considered best. Later smiths are only trying to recreate them. They may have succeeded in copying the shape but then fail at other features.

Jigane - Consistancy is a big deal. Strong clean jigane expressed over the full length of the sword is most appreciated. This is true even when the jigane is larger, wilder patterend but is expressed fully throughout. Later smiths may have been successful at reproducing good jigane but then fail at other features.

Hataraki - go to the glossary of any good sword book and there is a long list of features one wants to see in a sword. Read the description of celebrated Kamakura pieces and you can expect to find most of these features mentioned. Later pieces may have lots of hataraki in the ji or in the ha but are lacking in other areas.

Hamon - "temperlines" are expressed in more naturalistic ways showing an artlessness that may not always be found in later works.

Nakago - a well finished and perfectly aged nakago is a thing of beauty, the simple handwriting of the signature shows the artists origins as a simple craftsmen. Later signatures can be wonderful, but they reflect the education and erudition of the smith, become more like trademarks and are appreciated for different reasons.

 

Few later smiths combine all the best features in a single work, most of the celebrated Kamakura artists consistently hit high marks in all areas in the majority of their works.

 

This in the end is just my poor understanding of how we are to look at these works...

 

-t

[Rivkin]

1 hour ago, Jussi Ekholm said:

Here is also quite interesting article by Usagiya. I believe Keiun Naohiro made two kobuse constructed blades from same steel block (using this as the outer jacket). Aiming for Norishige like appearance.

 

h

 

You can see the pictures in the link above, I will just quote his thoughts on subject.

 

 

Lots of very interesting articles at Usagiya.

 

The author asserts that the steels cannot be mistaken for one another since one of the blades is processed in Norishige style.

I would disagree.

The Norishige style is of Ikkansai Yoshihiro's school type - mostly nioi, as if painted by ink, somewhat artificial looking as if wielded from plastic stripes, typical shinshinto and later appearance. In the other piece the hada is simply much denser, so it was folded a few more times, but it still has shinshinto appearance.

They "escaped" the tight itame for the sake of something "Norishige like" by manner of forging and heat treatment, but still the steel places hard limit on how far they can go. You can force it into any pattern, but the result will lack both depth and variety.

[Rivkin]

I pesonally like Nambokucho sugata the best, both tanto and daito.

The very end of Kamakura and Nambokucho are probably also the most imitated examples.

Classic Kamakura... aside from early Muromachi I fail to come up with a list of imitators.

[Jussi Ekholm]

On the Usagiya example as they both used the same prepared steel block, I believe they both were expected to have "Norishige like treats". I would have assumed that they would have appeared quite similar.

 

Here is another example from the smith where he used same steel block divided by two to make 2 swords from it. http://www.ksky.ne.jp/~sumie99/difference of tempering.html

 

Unfortunately I am not a science guy so I cannot really comment on these things nor a craftsman who would make items.

[Rivkin]

Another one I think shows Bizen style forging.

[Jacques D.]

4 hours ago, ROKUJURO said:

Mark is correct and has understood the process.

The idea that HADA will only show if made of two (or more) components may have derived from the modern Damascus principle: Two (or more) steel components of different composition are fire-welded together, and the final process after forging, heat-treament and grinding/polishing is an acid treatment. The metal layers will be attacked differently by the acid (or iron chloride solution) and show different colour - one steel may become black (manganese steel), another one does not react so much with the acid and remains silver (nickel-alloyed steel). This results in strongly contrasting pattern in the surface of the blade.

Long Japanese blades are not made this way. Here, the principle is a composite inner structure (KITAE) of two or more components (I don't mention the TANTO which are made of mono-steel), and each of these is made of thoroughly refined (= homogenized) steel.

The principle behind that is that you can exoect predictable properties only from perfectly homogenized material. This explains also, why many blades (often KAZU UCHI MONO) failed in combat which were made hastily by lesser smiths to equip troops in a less costly way.

 

Core steel (SHIN-TETSU) with lower carbon content was usually folded 12 to 15 times, sometimes even more. This lowered the carbon content, and in combination with KAWA-GANE (roughly 0,5 - 0,7% C) allowed for a flexible blade with very good cutting properties.

 

So please leave the idea beside that HADA in KAMAKURA JIDAI shows up because there were two steel components. The JIGANE was pefectly homogeneous steel!

Much later in Japanese history we see blades with stronger contrast of different materials in the JIGANE. This was intentionally made and the result of combining steels with alloying components (NANBAN TETSU and others).

 

Just ask a Japanese swordsmith like I did.  

 

Taro Asano and me discussing this topic

[ROKUJURO]

So did I, also in Besançon. 

[Bryce]

G';day Guys,

I am not sure how these examples fit into this argument, but below are two examples of Gassan Sadakatsu's work. On the left is a blade done in ayasugi and clearly two different steels have been layered to create the contrast. On the right is one in masame using I assume a single homogenous steel with only the welding seams between layers visible.

Cheers,

Bryce

[mas4t0]

Does anyone have easy access to a high-resolution electron microscope?

 

If so, they'd be able to see what's going on.

 

From Physics and Engineering of New Materials pp 305–310 (link to book); this is regarding wootz specifically, but the same method of inspection should work with Nihonto:

 

Using high-resolution electron microscopy, we have found in a sample of Damascus sabres from the 17th century both cementite nanowires and carbon nanotubes. These might be the missing link between the banding and ancient recipes to make that ultrahigh carbon steel. The sample considered belonged to the wootz-type of Damascus steel which is fundamentally different from welded Damast. The nanotubes have only been revealed after dissolution of the sample in hydrochloric acid. Some remnants showed not yet completely dissolved cementite nanowires, suggesting that these wires were encapsulated by carbon nanotubes. Only recently, considerable progress has been achieved in reproducing the process of making the characteristic pattern of wootz. We propose a connection between impurity segregation, nanotube formation, nanotube filling with cementite, cementite wire growth, and formation of large cementite particles. Needless to say that the presence of a nanostructure will have an impact upon the mechanical properties.

 

I'm not suggesting that Nihonto are made from a steel similar to wootz, or that the findings would be similar - just that the methodology (using an electron microscope) should establish clearly what it is that we're seeing.

[Rivkin]

I personally lost the sense of what is being argued awhile ago. Is traditional Japanese steel inhomogeneous? Yes, and it was sufficiently studied. There are many sources of inhomogeneous properties in any bloomery process, one of them is indeed the size, since the heat loss occurs mostly at the surface, and thus large bloomeries or "blast furnaces" tend to be produce better material...

There are blades made from modern and reasonably homogeneous steel (from Battleship Mikasa to gun barrels and anchors) and admittedly the hada is poor, but it is present. Yes older, more non-uniform and less thermally conductive steel offers greater options for pattern creation and manipulation. No matter how one forges, unless one has the right steel a very active blade cannot be created. It will either crack, or will look plasticky. Ikkansai Yoshihiro with all possible respect to his school, demonstrated well what happens when one takes essentially couple of different modern, homogeneous steels and tries to evolve them into the basis for traditional craft.

 

The steel always attracts a lot of claims that should not be. From Academic people not understanding traditional metallurgy and thus assigning to wootz some magic properties nobody ever observed (i.e. high carbon "steel" kind of behaves like pig iron doped with phosphorus and sulfur) to smiths whose understanding of metallurgy as a discipline is near non-existent in the first place. 

[Alex A]

13 hours ago, Toryu2020 said:

Jean - enjoying your comments and I like the points you have made.

 

I would posit that your example of the use of namban tetsu is not a good analogy. We were taught that the amount of namban tetsu used in the famous Yasutsugu swords (for example) was miniscule - just enough to say that he used some as it was a novelty and it added nothing to the overall product. His jigane I think most would see as quite clean and consistent so not a deliberate "damascene" hada.

 

I think Yakumo-gitae or the Shin Ju-go-mai of Omura Kaboku would be better examples of later smiths using mixed metals for effect.

 

Alex - the short answer to the question is "You need a full education in nihonto to appreciate why Kamakura is the best." ( I was told the same thing when I started btw) The long answer is below;

 

Sugata - the shapes produced in this time period are considered best. Later smiths are only trying to recreate them. They may have succeeded in copying the shape but then fail at other features.

Jigane - Consistancy is a big deal. Strong clean jigane expressed over the full length of the sword is most appreciated. This is true even when the jigane is larger, wilder patterend but is expressed fully throughout. Later smiths may have been successful at reproducing good jigane but then fail at other features.

Hataraki - go to the glossary of any good sword book and there is a long list of features one wants to see in a sword. Read the description of celebrated Kamakura pieces and you can expect to find most of these features mentioned. Later pieces may have lots of hataraki in the ji or in the ha but are lacking in other areas.

Hamon - "temperlines" are expressed in more naturalistic ways showing an artlessness that may not always be found in later works.

Nakago - a well finished and perfectly aged nakago is a thing of beauty, the simple handwriting of the signature shows the artists origins as a simple craftsmen. Later signatures can be wonderful, but they reflect the education and erudition of the smith, become more like trademarks and are appreciated for different reasons.

 

Few later smiths combine all the best features in a single work, most of the celebrated Kamakura artists consistently hit high marks in all areas in the majority of their works.

 

This in the end is just my poor understanding of how we are to look at these works...

 

-t

 

Hi Thomas, yes i get all that.

 

The issue now is folk going way off track and into space with regards hada.

 

My last comment was just a thought, thinking if folk cant work out how differing carbon during construction effects hada (even though stated numerous times) then what hope is there in ever trying to work out the visible steel effect of Kamakura blades to that of other blades, with regards construction/materials.

 

It should have stopped in my opinion at Rays post about the smith Shibata Ka, as NO ONE here has the knowledge to answer that question, unless your at that guys level as a SMITH.

 

As said, i will just stick with what is written about hada, good enough for me, this is heading for an egotistical mess. sigh.

 

Ps, Nice one Jacques & Jean speaking to someone in “the know”.

 

[Jacques D.]

9 hours ago, ROKUJURO said:

So did I, also in Besançon. 

Seeing him is not the proof you talk with him as i did. 

 

Two scientific studies which contradict you (I would like to see evidence to support your assertions) 

 

http://www.nihontomessageboard.com/articles/Study_of_Japanese_sword_from_a_viewpoint_of_steel_strength.pdf

http://www.militaria.co.za/articles/Characteristics_of_Japanese_sword_produced_from_tatara_steel.pdf

[Alex A]

Thats what ive been thinking…evidence

[mas4t0]

5 hours ago, Jacques D. said:

Seeing him is not the proof you talk with him as i did. 

 

Two scientific studies which contradict you (I would like to see evidence to support your assertions) 

 

http://www.nihontomessageboard.com/articles/Study_of_Japanese_sword_from_a_viewpoint_of_steel_strength.pdf

http://www.militaria.co.za/articles/Characteristics_of_Japanese_sword_produced_from_tatara_steel.pdf

 

Along that same line (if we're being skeptical) a photo of two people seemingly engaged in conversation is not proof of what was said or proof that a conversion actually took place.

 

What in those studies do you think contradicts what Jean wrote?

 

The conclusion from Characteristics of Japanese sword produced from tatara steel:

 

The short sword prepared from tamahagane by traditional technique was observed by optical microscopy and SEM/EBSD measurements. The sizes of lath martensite were identified with average block thickness 0.47 um and packet size 3.6 um, respec­tively, which were smaller than those of Fe–C steel. The morphology of packet and prior austenite grain boundaries were quantified, and it was found that the boundaries in the short sword has small cur­vature and small ratio of straight line compared with ordinary Fe–C steel. It was understood by this analysis that grain boundary of the short sword is short wavelength wavy patterns.

 

The conclusion from Study of Japanese sword from a viewpoint of steel strength:

 

Four-point bending test has been performed to estimate the strength of Japanese sword for the first time in addition to a series of metallurgical investigations. The observed main features are as follows:

 

The microstructure of sharp edge in Japanese sword is fine lath martensite, resulting high hardness.

 

The sharp edge has extremely large compressive stress like car­bonized steels. This stress should contribute to steel strength of sharp edge greatly.

 

The strength of 4645 MPa for sharp edge in modern sword was measured, and the fracture surface after bending test showed that the crack propagation behavior and the change in the macroscopic direction of propagation were observed.

 

I read both papers thoroughly, but must have somehow missed the parts relevant to this discussion. Would you be so kind as to quote them or direct me to them?

 

Are you perhaps referring to this passage?

 

These swords are found to be composed of two kinds of middle carbon steel, outside and low carbon steel, inside. In other words, Japanese sword is one of composite materials. There are hardly harmful impurities such as Si and Mn which decrease the sword quality.

 

This is referring to lamination (as shown below) as opposed to blending them together to form hada.

 

 

I don't see any discussion regarding two dissimilar steels being blended to form hada.

 

Having read both papers I'm quite confused as to what you and Alex see as evidence relevant for this discussion. I must have missed it and would very much appreciate clarification.

[Alex A]

Looks like everyones looking for evidence 

 

Just an humble hada student wondering why some folk disagree with what has been stated elsewhere and trying to get my head around why folk are saying what they are saying, without anything to back up their statements.

 

As said, this not a speciality of mine, obviously.

 

Just curious.

 

PS, Mark.

It states “composed of TWO KINDS of middle carbon steel”

 

Lets not split hairs.

 

Also, Nicolas, sorry!, 

[Nicolas Maestre]

15 hours ago, Toryu2020 said:

 

Alex - the short answer to the question is "You need a full education in nihonto to appreciate why Kamakura is the best." ( I was told the same thing when I started btw) The long answer is below;

 

Sugata - the shapes produced in this time period are considered best. Later smiths are only trying to recreate them. They may have succeeded in copying the shape but then fail at other features.

Jigane - Consistancy is a big deal. Strong clean jigane expressed over the full length of the sword is most appreciated. This is true even when the jigane is larger, wilder patterend but is expressed fully throughout. Later smiths may have been successful at reproducing good jigane but then fail at other features.

Hataraki - go to the glossary of any good sword book and there is a long list of features one wants to see in a sword. Read the description of celebrated Kamakura pieces and you can expect to find most of these features mentioned. Later pieces may have lots of hataraki in the ji or in the ha but are lacking in other areas.

Hamon - "temperlines" are expressed in more naturalistic ways showing an artlessness that may not always be found in later works.

Nakago - a well finished and perfectly aged nakago is a thing of beauty, the simple handwriting of the signature shows the artists origins as a simple craftsmen. Later signatures can be wonderful, but they reflect the education and erudition of the smith, become more like trademarks and are appreciated for different reasons.

 

Few later smiths combine all the best features in a single work, most of the celebrated Kamakura artists consistently hit high marks in all areas in the majority of their works.

 

This in the end is just my poor understanding of how we are to look at these works...

 

-t

 

Thank you Thomas for bringing this topic back on track 😊. Not that the whole Hada discussion is off, because it clearly isn’t since it’s part of what makes those blades so unique if I understand well. But the peeing contest / “I know and you don’t” thing, is detrimental to everyone imo.

 

Anyways, little did I know that this question would bring so many views and would be so complex. But the read has been very enlightening so far!

 

Question if you don't mind: I can totally understand the points made around Hada, Hataraki, etc. But the shape?? How would you even consider the shape as part of the equation when most of the blades (Kamakura) are Suriage, and you can therefore not have a look at what the smith created in the first place? I mean, the Sugata we see today is only due to a dude, several decades or even centuries later, choosing to cut here, or hmmmmm, nope, maybe here… and boom, it’s the shape you see now! I’m genuinely asking, not trying to be disrespectful or anything 😊.

[Gakusee]

43 minutes ago, Nicolas Maestre said:

 

Thank you Thomas for bringing this topic back on track 😊. Not that the whole Hada discussion is off, because it clearly isn’t since it’s part of what makes those blades so unique if I understand well. But the peeing contest / “I know and you don’t” thing, is detrimental to everyone imo.

 

Anyways, little did I know that this question would bring so many views and would be so complex. But the read has been very enlightening so far!

 

Question if you don't mind: I can totally understand the points made around Hada, Hataraki, etc. But the shape?? How would you even consider the shape as part of the equation when most of the blades (Kamakura) are Suriage, and you can therefore not have a look at what the smith created in the first place? I mean, the Sugata we see today is only due to a dude, several decades or even centuries later, choosing to cut here, or hmmmmm, nope, maybe here… and boom, it’s the shape you see now! I’m genuinely asking, not trying to be disrespectful or anything 😊.

Nicolas

Plenty of ubu Heian and Kamakura blades are available. What the smith intended is very obvious. Also there are plenty of extremely well preserved Kamakura blades. They are just too precious to test against kabuto or steel rods or new swords . 
 

I feel we need to shortcut the whole discussion and in the fashion of how some of the scientific papers are structured, quote what has been already discussed and invoke existing research and use it to substantiate elements of the thesis in order to crystallise overall conclusions with that “evidence”:

- There was another NMB topic about which the greatest smiths were. In there you might see that the most reputed, highly regarded smiths with the most Kokuho/JuBu/JuBi/TJ blades are actually Kamakura and Heian smiths. In here I of course include most of the Soshu greats, although there is a minor crossover into the very beginning of Nanbokucho. By extrapolation,  if the greatest smiths worked mainly / predominantly during the Kamakura period then the Kamakura blades  seem to be evaluated as the best. Not equivalent logically but intuitively you understand the Japanese belief. Just on average they seem to be better, not that it always holds. 
- Why are the aforementioned the greatest/ most highly reputed smiths etc? Well, Japanese emperors, Daimyo and Shogun decided so and we have followed their taste (as it often happens in Japanese culture / history). It is down to a combination of myth + personal taste (eg Gotoba ushering a certain sense of aesthetic or the Ashikaga shogun preferring certain aspect and also thereafter Oda, Toyotomi and Tokugawa favouring Soshu and Bizen etc) + performance in the respective historic period. 

- Again why / what to look for / understand why the aforementioned Daimyo etc decided as mentioned above: look at Tom Helm’s post explaining the physical features 

- also consider Chris Hill’s historic diagram (you need to understand normalisations as he has statistically normalised certain things) demonstrating where/ in which period you had the peak of top-rated blades. It clearly shows you the explosion in Kamakura. 

 

Honestly, it is not such a difficult question to address. Overall, it is a matter of understanding Japanese aesthetic, history and culture and then interpreting the question through that cultural and social prism. It has little to do with Western perceptions of which steel is best (modern man made vs Japanese - old /new) or even old Japanese (Kamakura) vs newer. A lot of it is simply tradition-  and acquired-aesthetic-based. 
 

Separately, and subjectively,  I agree with some of the posts above that the exciting / differentiated / lively Kamakura hada interspersed with scintillating jinie and konie of Kamakura, or the elegant utsuri of the period are aesthetically superior to the more monotonous or lifeless or homogeneous output of the later periods. Or even when some of the later (eg Shinto or ShinShinto) smiths achieve something outstanding, as an aggregate, across the population of smiths, on average you cannot say that the blades are so pretty or interesting. 

[ROKUJURO]

As there seem to be more opinions than metallurgical facts, I wrote to ASANO TARO today, asking for his expert statement. I hope he will reply, but it is certainly not easy for him in English. Unfortunately, my Japanese is insufficient for this.

For Jacques:
In 2014, I had the pleasure to assist ASANO-SAN in his forging demonstration in France. I gave him some of my home-made TAMAHAGANE which he tested and later used for sword-making. We are in permanent contact as good friends and collegues. And of course we talked about all aspects of forging, as far as the language barrier would allow.

[Alex A]

Hate to state the obvious but is sword making not too diverse to say one size fits all, with regards the way various steels are used, mixed or whatever ?, just a thought that occurred. Read a few varying tales on the internet a short while ago with regards the outer steel and now feel you cant put everything into handy boxes, as is the case quite often in this hobby.

 

Be good to hear what yours and Jacques pal says about carbon and hada definition, my main interest in this offshoot 

 

Nicolas, again apologies. Not a bad side-line though as this talk is fundamental to the hobby,.

 

Cheers.

 

 

 

 

[Toryu2020]

I can hardly add to what Michael has so succinctly said,

 

Nicholas - the blade I posted earlier, which is from the very beginning of Namboku-cho, is ubu signed and dated. As Michael points out there are plenty of ubu Kamakura pieces out there and once you become familiar with sugata, I think you can appreciate the shapes as the Japanese do...

 

-t

[Alex A]

1 hour ago, Gakusee said:

Nicolas

Plenty of ubu Heian and Kamakura blades are available. What the smith intended is very obvious. Also there are plenty of extremely well preserved Kamakura blades. They are just too precious to test against kabuto or steel rods or new swords . 
 

I feel we need to shortcut the whole discussion and in the fashion of how some of the scientific papers are structured, quote what has been already discussed and invoke existing research and use it to substantiate elements of the thesis in order to crystallise overall conclusions with that “evidence”:

- There was another NMB topic about which the greatest smiths were. In there you might see that the most reputed, highly regarded smiths with the most Kokuho/JuBu/JuBi/TJ blades are actually Kamakura and Heian smiths. In here I of course include most of the Soshu greats, although there is a minor crossover into the very beginning of Nanbokucho. By extrapolation,  if the greatest smiths worked mainly / predominantly during the Kamakura period then the Kamakura blades  seem to be evaluated as the best. Not equivalent logically but intuitively you understand the Japanese belief. Just on average they seem to be better, not that it always holds. 
- Why are the aforementioned the greatest/ most highly reputed smiths etc? Well, Japanese emperors, Daimyo and Shogun decided so and we have followed their taste (as it often happens in Japanese culture / history). It is down to a combination of myth + personal taste (eg Gotoba ushering a certain sense of aesthetic or the Ashikaga shogun preferring certain aspect and also thereafter Oda, Toyotomi and Tokugawa favouring Soshu and Bizen etc) + performance in the respective historic period. 

- Again why / what to look for / understand why the aforementioned Daimyo etc decided as mentioned above: look at Tom Helm’s post explaining the physical features 

- also consider Chris Hill’s historic diagram (you need to understand normalisations as he has statistically normalised certain things) demonstrating where/ in which period you had the peak of top-rated blades. It clearly shows you the explosion in Kamakura. 

 

Honestly, it is not such a difficult question to address. Overall, it is a matter of understanding Japanese aesthetic, history and culture and then interpreting the question through that cultural and social prism. It has little to do with Western perceptions of which steel is best (modern man made vs Japanese - old /new) or even old Japanese (Kamakura) vs newer. A lot of it is simply tradition-  and acquired-aesthetic-based. 
 

Separately, and subjectively,  I agree with some of the posts above that the exciting / differentiated / lively Kamakura hada interspersed with scintillating jinie and konie of Kamakura, or the elegant utsuri of the period are aesthetically superior to the more monotonous or lifeless or homogeneous output of the later periods. Or even when some of the later (eg Shinto or ShinShinto) smiths achieve something outstanding, as an aggregate, across the population of smiths, on average you cannot say that the blades are so pretty or interesting. 

 

Good write-up

 

However, we are still left with the question on how they made superior blades

[Jacques D.]

Jean,

There is something that bothers me, on the one hand you say this :

 

Quote

 

I am sorry, but this is dead wrong. Are you referring to the (wrong) theory that Damascus steel consists of layers of different hardness? This is certainly also not the case in Japanese blades.

 

 

 

 

 

and on the other you say that (picture below)

 

 

Wouldn't it be like a contradiction. 

ps my house is near Besançon, I was at the citadel every day during this event and I know the blacksmith who served Taro Asano as sakite, it is Robert Greset.  We see you on this video.

 

https://france3-regions.francetvinfo.fr/bourgogne-franche-comte/doubs/besancon/rencontre-forgerons-deux-mondes-citadelle-besancon-533008.html

 

 

[mas4t0]

23 minutes ago, Jacques D. said:

Jean,

There is something that bothers me, on the one hand you say this :

 

 

and on the other you say that (picture below)

 

 

Wouldn't it be like a contradiction. 

ps my house is near Besançon, I was at the citadel every day during this event and I know the blacksmith who served Taro Asano as sakite, it is Robert Greset.  We see you on this video.

 

https://france3-regions.francetvinfo.fr/bourgogne-franche-comte/doubs/besancon/rencontre-forgerons-deux-mondes-citadelle-besancon-533008.html

 

 

 

Is this English translation correct?

 

Quote

 

Materials for cutting edges and blades

I forge my tools and knives primarily from different carbon steels, the alloy of which is adapted to the intended use. Some steel comes from recycling - in a forge, not even the smallest nail ended up in the waste! Robust, large knives for chopping and other rough work can be made of spring steel (there are a number of variants). I make knives for fine-cutting tasks from high-carbon steel, for which old files and ball bearing rings from recycling are a good and almost never-ending source. I also use various industrial tool-steels.

These steels are not stainless, but they have other properties that are more important to me: with the right heat treatment, very fine, durable edges can be produced, which can be easily re-sharpened later if necessary with a few good bench stones. In addition, the risk of corrosion is low if the blades are cared for regularly.

For special purposes, e.g. historical replicas (I also work for museums), I use composite techniques. High-performance cutting edges made of highly hardenable steel are welded into a tough-elastic blade body.

I also forge Damascus steel from different steels, which are combined with each other in such a way that the finished blade has a clearly visible structure after etching.

Depending on the application, my workpieces are hardened or tempered differently so that they can optimally fulfil their tasks. Some knives are differentially hardened - a technique that is known to be typical for Japanese edged weapons (HAMON), but which was practised in Europe long before that.

 

 

 

 

There's no contradiction there with relation to the thread. Pattern welding and lamination are two different things. You could do both in a single blade, but you can also make a blade of pattern welded steel with no lamination or a laminated blade with no pattern welding or hada (as in a san-mai blade with stainless steel cladding and a carbon steel core).

 

I'll add some photos:

 

"Coreless-damascus" blade showing pattern welded steel (dissimilar alloys) with no lamination:

 

 

Stainless san-mai laminated blade, with no pattern welding or hada, but with a core of carbon steel (for the cutting edge) sandwiched between a layer of stainless steel on each side:

 

 

Stainless "damascus" (i.e. pattern welded) cladding on a san-mai laminated blade with a tool-steel (CPM-M4) core:

 

[Jacques D.]

Mark 

About the study, I'm not sure if you understood what you read, it's not about shihozume  but about a mix of two medium hard steels (medium hard steels have a carbon content from 0.3% to 0.6%) and a soft steel core.  Figure 2 shows the difference between the two swords

 

 

Quote

There's no contradiction there with relation to the thread.

 

Reread my comment and what is framed in red with the finger. 

 

[Nicolas Maestre]

 

2 hours ago, Gakusee said:

Nicolas

Plenty of ubu Heian and Kamakura blades are available. What the smith intended is very obvious. Also there are plenty of extremely well preserved Kamakura blades. They are just too precious to test against kabuto or steel rods or new swords . 
 

I feel we need to shortcut the whole discussion and in the fashion of how some of the scientific papers are structured, quote what has been already discussed and invoke existing research and use it to substantiate elements of the thesis in order to crystallise overall conclusions with that “evidence”:

- There was another NMB topic about which the greatest smiths were. In there you might see that the most reputed, highly regarded smiths with the most Kokuho/JuBu/JuBi/TJ blades are actually Kamakura and Heian smiths. In here I of course include most of the Soshu greats, although there is a minor crossover into the very beginning of Nanbokucho. By extrapolation,  if the greatest smiths worked mainly / predominantly during the Kamakura period then the Kamakura blades  seem to be evaluated as the best. Not equivalent logically but intuitively you understand the Japanese belief. Just on average they seem to be better, not that it always holds. 
- Why are the aforementioned the greatest/ most highly reputed smiths etc? Well, Japanese emperors, Daimyo and Shogun decided so and we have followed their taste (as it often happens in Japanese culture / history). It is down to a combination of myth + personal taste (eg Gotoba ushering a certain sense of aesthetic or the Ashikaga shogun preferring certain aspect and also thereafter Oda, Toyotomi and Tokugawa favouring Soshu and Bizen etc) + performance in the respective historic period. 

- Again why / what to look for / understand why the aforementioned Daimyo etc decided as mentioned above: look at Tom Helm’s post explaining the physical features 

- also consider Chris Hill’s historic diagram (you need to understand normalisations as he has statistically normalised certain things) demonstrating where/ in which period you had the peak of top-rated blades. It clearly shows you the explosion in Kamakura. 

 

Honestly, it is not such a difficult question to address. Overall, it is a matter of understanding Japanese aesthetic, history and culture and then interpreting the question through that cultural and social prism. It has little to do with Western perceptions of which steel is best (modern man made vs Japanese - old /new) or even old Japanese (Kamakura) vs newer. A lot of it is simply tradition-  and acquired-aesthetic-based. 
 

Separately, and subjectively,  I agree with some of the posts above that the exciting / differentiated / lively Kamakura hada interspersed with scintillating jinie and konie of Kamakura, or the elegant utsuri of the period are aesthetically superior to the more monotonous or lifeless or homogeneous output of the later periods. Or even when some of the later (eg Shinto or ShinShinto) smiths achieve something outstanding, as an aggregate, across the population of smiths, on average you cannot say that the blades are so pretty or interesting. 

 

Very nice write-up indeed! Thanks 👍

Ok so my initial statement referring to how rare Ubu Kamakura blades are is kinda wrong 😁. The thing is that every blade I stumbled upon online seems to be suriage... Oh and also this article from Markus Sesko was pretty clear about it (last paragraph).

 

Thanks to you all, I think the bigger picture is now much, much clearer for me... I love this forum 👍

 

2 hours ago, ROKUJURO said:

As there seem to be more opinions than metallurgical facts, I wrote to ASANO TARO today, asking for his expert statement. I hope he will reply, but it is certainly not easy for him in English. Unfortunately, my Japanese is insufficient for this.

 

Can't wait to read what his take is on the subject!!

 

1 hour ago, Alex A said:

Nicolas, again apologies. Not a bad side-line though as this talk is fundamental to the hobby,.

 

Cheers.

 

Oh no need to apologize 😉. As I said I totally agree that it is an important part of the equation here.

[Jean]

BTW, this subject was already treated years ago on NMB and I remember Darcy had participated to the topic, it seems that the golden period spanned from roughly 1150 to 1350

[mas4t0]

4 hours ago, Jacques D. said:

Mark 

About the study, I'm not sure if you understood what you read, it's not about shihozume  but about a mix of two medium hard steels (medium hard steels have a carbon content from 0.3% to 0.6%) and a soft steel core 

 

 

 

Reread my comment and what is framed in red with the finger. 

 

 

This section?

 

I also forge Damascus steel from different steels, which are combined with each other in such a way that the finished blade has a clearly visible structure after etching.

 

"Damascus" is a commonly used term to refer to pattern-welded steel. It is true that the pattern of "damascus" is revealed through etching (I believe Jean gave a brief overview of the relevant Chemistry earlier in this thread).

 

But Japanese swords are not "damascus" and the hada is revealed by polishing on stones (as you described earlier).

 

 

In the image above they've delineated the three regions and you can visually observe the lamination layers. 1) The "sharp edge" 2) the "side plane" and 3) the "core region". This would seem to correspond to:

 

These swords are found to be composed of two kinds of middle carbon steel, outside [i.e. "sharp edge" and "side plane"] and low carbon steel, inside [i.e. "core region"]. In other words, Japanese sword is one of composite materials. 

 

*[ ] added by me

 

It seems like a very liberal and creative reading of the text to consider the above quote as referring to layers in the hada (which isn't pictured) as opposed to the macro structure (which are shown and annotated).

 

If there were discussing hada being formed from two different kinds of middle carbon steel I would have expected some more information on how they established this fact.

 

I'm not sure precisely what's meant by "different kinds of middle carbon steel". I had presumed that it referred to different levels of carbon content (which would indicate lamination). For the reasons explained by Jean earlier, unless the layers were relatively thick (and the pattern-welding took place after refinement of the steel), you wouldn't maintain a meaningful difference in carbon content between layers in the hada.

 

Of course I could well be mistaken. My degree only included a couple of courses on metallurgy and I only have a handful of textbooks on the topic - which is to say that while I have a basic grasp of smelting, heat treat, alloying, etc and familiarity with relevant terms and concepts (eutectoids, carbides, unit cells, microstructures, grain, etc) I obviously know very little compared to a specialist (be that a smith or a metallurgist).