Iron or steel Tsuba

[Baka Gaijin]

Here's a question that has been perplexing me......

 

What is the main difference between Iron and Steel related to Tsuba?

 

 

Malcolm

[Brian]

Malcolm,

Don't think I can give a better answer than this one:

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

 

Brian

[Ford Hallam]

just to add to what Brian has found...(which is a good outline ) I think we can be reasonably sure that most ferrous tsuba, of whatever period, are made from a basic, low carbon content steel. Something that isn't all that different in terms of composition from mild steel. There are some analysis's of ferrous tsuba from the late Edo period that in fact show them to be almost without any carbon. I think these are possibly typical of the sort of material used for tsuba that feature a lot of elaborate carving.

 

I'd suggest that certain schools. Akasaka, Myochin, Higo etc( those with more warrior class associations)...were using steel with at least nominal carbon content ( remember that a sword is typically only 0.7% carbon steel, this is the same as basic spring steel, like the stuff on truck suspension leaf springs).

 

I am doubtful of the various claims made about relative hardness and state of tempering etc. I don't believe it possible to discern these details by feel and touch....or sound for that matter. I'm also unaware, despite quite a few years searching, of any serious scientific research into these aspect of steel tsuba. Would you drill out a core sample from a Kanie tsuba? and surface analysis ( by whatever method ) of patinated steel is completely inaccurate so I imagine we'll have to keep guessing

 

Like a lot of the, apparently, technical pronouncements made by tsuba aficionados much is pure speculation and regurgitating of received wisdom. Unfortunately there is little verification of the basic principles of metallurgy or craft practices, which in turn leads to some of the most wildly spurious claims.

 

As the saying goes; " in the land of the blind the one eyed man is king" :D

 

ok....rant over ...normal service will be resumed shortly :|

 

regards, Ford

[Bungo]

" am doubtful of the various claims made about relative hardness and state of tempering etc. I don't believe it possible to discern these details by feel and touch "

 

Just personal observation only, mind you.

I believe the relative " hardness " of different schools are derived from visual observation, like a Armour.sword maker tsuba " appear " harder than , say, a Choshu/Bushu tsuba. Ito tsuba with those thin cut out " appear " soft as the technique will be very difficult to execute with " hard steel " ?

 

When scrapping red rust from various " low end " tsuba from different period/school, I do feel a difference ( hardness ? ).

 

milt

[Ford Hallam]

appearances can be so deceptive...don't you think?

 

as for feeling a difference when scraping rust...this doesn't really tell us much about carbon content or relative hardness....merely subjective, tactile feedback. Worth making the point and trying to isolate that aspect of empirical "evidence" though....the cigar is on it's way

 

cheers, Ford

[Bungo]

when one is blind, one depends on feel........... didn't say it's scientific.

 

But most would agree Ito/Choshu type iron " appears " " softer " than that of Tosho, Saotome, yes ?

 

 

milt

[Baka Gaijin]

Thank you one and all for the input.

 

Question answered and more questions generated.

 

That's the beauty of this Forum.

 

Malcolm

[Mike]

Hi, interesting thread on the same toic on other forum http://www.nihontokanjipages.com/forum/ ... php?id=366

 

Mike

[Brian]

I'm getting no permission to view. Has it gone members only?

 

Brian

[Bungo]

I'm getting no permission to view. Has it gone members only?

 

Brian

 

your disposable asset does not meet our minimal requirement.........no soup for you.

 

milt

[Brian]

That is very true. If you think the $ has dropped, try a 20% drop in our currency against the USD the past 2 weeks

Ok..back to the topic.

 

Brian

[Ford Hallam]

Thanks for that link, Mike.

 

as you say, very interesting discussion. Without throwing myself into the debate ( as I'm too often keen to do ) I'd just like to offer my commentary on Boris's "empirical" check list for distinguishing iron from steel tsuba. I hope this will be seen in a neutral light and merely as an attempt to establish observational criteria that are more grounded in verifiable data.

 

I've quoted Boris's points and posted my comments after each section to try to keep it all clear.

 

I hate to say it, but my methods are totally empirical.  I think iron is easier to recognize than steel, so I look for a combination of as many of the following characteristics as possible: 

 

1) Softer look - This can manifest itself through deeper, more defined tsuchime on the plate - more malleable metal

The texture of the metal is completely dependant of the type of hammering it was subjected to and subsequent corrosion…this in no way is indicative of it’s relative hardness.

 

2) Patina - I think that early iron tends to patinate more towards a brown / black and typically demonstrates less of a sheen or metallic lustre

 

The colour of ferrous alloy corrosion products ( ie; patinae) is more likely to be affected by atmospheric pollutants than its actual carbon content. Colour cannot help define carbon content.

 

3) Tekkotsu - larger or varied tekkotsu suggest a metal which has not had the carbon evenly distributed, thus less working of the metal.

 

Good point, but as the material obviously has large accumulations of carbon it must be classed as a steel…however crude and inhomogeneous.

 

4) Folding (if visible) is more commonly defined by tekkotsu in the mimi

As we’re already agreed, tekkotsu is evidence of higher carbon content….so it must be steel.

 

5) Surface treatments such as file marks, yasurime and zogan grooves tend to have more definition and are more commonly associated with iron pieces - likely due to the increased ease of execution.

In fact the difference in ease, or difficulty of execution of refined decoration, whether by file, hammer or chisel is virtually nil. If anything, steel ( as opposed to pure iron ) allows for a far more crisp and precise marks.

 

 

For steel tsuba, I would look for absence of lack of definition of the above points, and the addition or substitution for the following characteristics:

 

1) Dense, hard metal with less surface treatment such as tsuchime, file marks, etc...

As I’ve already pointed out, hardness cannot be discerned reliably by visual means alone. Apparent density of the metal could perhaps be discerned but this would be evidence of the degree of working not its composition. The absence of surface decoration tells us nothing about the actual metal only the decision of the maker whether to decorate or not.

 

2) Lustrous, metallic sheen (not to be mistaken for over-cleaned pieces)

 

Again, a purely visual assessment that would be almost completely dependant on the condition of the piece.

 

3) Erosion patterns tend not to be too deep, but rather a variation in surficial topography.  Less likelihood of encountering red rust spots.

 

The suggestion here seems to be that steel is more resistant to corrosion than iron. If anything, there is some evidence that in certain cases the opposite is the case. Further, relative rates of corrosion and evidence of rust are all completely dependant on the conditions the piece has been subject to. All active rust is red anyway, regardless of the steel composition and the likelihood of encountering it is irrelevant to the assessment of an individual item.

 

4) Folding patterns (if evident) on the plate often will have crisper, finer edges suggesting a harder metal less prone to abrasion and bending.  Folds can be more complex - sinuous and traceable

 

There may be some value to this observation. More complex folding patterns may indicate a more refined material. I would make the point though, that hardness and abrasion resistance are not the same thing in metallurgical terms. It might be worth considering toughness as a more useful property of a tsuba.

 

5) Tekkotsu (if evident) tend to be very fine and granular, rather than large, clustered masses.  Like Nie in a blade.

Again, we have both definitions claiming the presence of tekkotsu as defining traits….the only difference being the degree of refinement. Both are still steel though.

 

I offer these comments only as my opinion ( albeit back by my experience as a professional craftsman and tsubashi, and my own researches into the working methods of old Japan). I welcome further debate and discussion as part of what I hope could be a useful clarification of this issue. I'm certainly not claiming that my observations are absolutely correct but only that in my view there is, as I trust I have demonstrated, a far from resolved matter to explore. I trust that Boris will read my comments in that spirit.

 

Regards,

 

Ford

[Rich T]

I'm getting no permission to view. Has it gone members only?

 

Brian

 

Yeah sorry about that, I hit a magic button, all good now though.

 

Nice continuation of the thread. I like the way you refrain from jumping in Ford

 

cheers

 

Richard

[Guido]

Not directed at anyone particular:

There are words in Japanese for steel - Kôtetsu 鋼鉄 - and iron - Testsu 鉄 - but one hardly ever finds Kôtetsu in (Japanese) descriptions; only Tetsu is used, be it Jitetsu 地鉄 when it comes to swords, or Tetsuji 鉄地 when dealing with Tsuba. If the Japanese (experts) don't care, why should *we* get all excited about it? This discussion might have some academical merit, but after all is said and done, the quality (or lack thereof) of the individual Tsuba is what we should focus our attention on.

[Guido]

I like the way you refrain from jumping in Ford

To quote my mother (who raised three sons, me being the eldest): "If you're going to kill each other, do it outside. I just finished cleaning!"

[Pete Klein]

Thank you Guido! ROFL

[Rich T]

I like the way you refrain from jumping in Ford

To quote my mother (who raised three sons, me being the eldest): "If you're going to kill each other, do it outside. I just finished cleaning!"

 

Ahhhhh, I am going to miss that sense of humor this October. Thanks Guido. Of course I was just having a little fun at Fords expense, no malice intended.

 

Rich

[Baka Gaijin]

Thanks Guys for all this great input and the links...

 

Can I extend the question slightly by asking if Hagane iron sand were to heated to liquid state and during this process carbon added, to 0.5 - 2.00%. Could it be poured into a mould or former and cooled as a flat sheet of steel, and could that be worked subsequently with chisels, files and saws etc?

 

Also while we're here, were acids used to "resist cut" areas on Iron/Steel tsuba?

 

If so, what schools please........

 

One for Ford perhaps.

 

Thank you all again for the input.

 

Malcolm

[Ted Tenold]

This is amounts to a somewhat contextual debate and there are good points by all. Ford makes some good observations based on composition and craftsmanship, Guido on broader academics and definitions (or the looseness thereof), and Boris on a individual collector's approach to judgement.

 

I'd offer the following;

 

Traditional steel production methods in Japan were dependant on smelting technology involving charcoal as fuel. The impartation of carbon into the material was going to be evident throughout the kera (block of material, or "bloom") in greater or lesser degrees depending on any given region of the finished kera that would be examined. Therefore, in *general* the entire kera would *technically* be one big block of steel. However there are illustrations in Tawara Kuniichi's book, Nihonto no Kagakuteki Kenkyu (Scientific Research of the Japanese Sword), showing cross sections of tamahagane, and the test results revealing the carbon content from pin-point areas. The results show that there are indeed small areas of 0% carbon, but they are very few. Other areas show very high concentrations that exceed 1%. Again, these are the exception rather than the norm. Therefore in any given piece, one could argue that it is indeed steel (though lacking uniform homogeneity) by default of carbon in any range of concentration.

 

When a kera is produced, there is only a small percentage of it that is suitable for sword production. This smaller amount of prime, higher grade material is more expensive and highly sought from each kera produced. Lesser grade material composes a larger percentage of the overall kera and though suitable for sword production, it will require more working and perhaps blending with other more suitable material to stretch the yeild. Then there remains a great portion of the kera that is not really suitable for sword production without great (and thus cost prohibitive) efforts to develop it further into acceptable material. These varied "grades" are evident in the production seen today in the Shimane based tatara (smelter).

 

So, given this and speculating from an approach of ancient prudence my theory is this; the remaining material, though unsuitable for swords, may have been perfectly suitable for other items such as, tea kettles, gate hinges, tansu brackets, handles, and yes, Tsuba and kodogu. Certainly there are parts of the kera that are not only too low in carbon for appropriate sword material, but also, as Dr. Tawara shows, also too *high*. Steel production and anything made from it becomes, in the end, an equation of labor and how to maximize it. Those prudently operating a smelter would certainly look to maximize the usage from each kera as well.

 

Looking at different tsuba producing schools/regions we see carbon inclusions of varied degrees manifested in both large and small "bones" in the surfaces, and the methods of how the maker worked the material to make it suitable for purpose. Linear tekkotsu that are finer, or bolder, and nodular tekkotsu that are fine to those that are huge. Some were folded several times, others only a few, therefore distributing the material of varied carbon content differently. The combinations of material origin, composition, carbon content, preperation, and treatment are obviously very exponential. The region of steel production in conjunction with the regional styles, flavors, judgement for material selection and working methods for that particular material all gave birth to the end results we study today, and indeed help us define their origins and quality.

 

Let's also look at the so called "Tosho" tsuba. It's speculated that these were originally were made by the swordsmith for the sword when produced. Would the smith use the most precious of sword making material for the production of a tsuba rather than another sword? Or, would it be more prudent to use material that was culled during the sword making process for the production of something ammenable to a different task (with ammenable working properties), while utilizing what was still a very valuable and expensive resource? I'd say the latter, which in my opinion explains a great deal about the finer textures, the softer look, colors, etc. of those tsubas. Katchushi tsubas also may also have been material that was culled away during production of armor, using techniques and methods of the armor maker. As the tsuba craft came to be a specialized and seperate trade, we see yet more differences in technical and material application, and let's face it, a poor quality tsuba begins with a poor quality plate.

 

So what are we really getting at here? Well, I'd offer that the differences between "Iron" and "Steel" in Japan are a combination of material chosen for specific task (i.e. intent), and the amount of refinement applied to that material to make a suitable raw material for the end product. I've never heard anyone speak of a "Steel Tea Kettle" or a "Steel Hinge". Yet, the material likely has some trace carbon and therefore at some level is steel, and alternatively I've never heard of an "Iron Katana". So calling an iron tsuba a “steel†tsuba seems out of context if for no other reason than by traditional intent. I would however call a tsuba a "Steel" tsuba if it were produced from a plate that was intended as applicable base material for any wide range of tasks, rather than a material selected (or culled) from another process and directed to a product where the material was catagorically suitable. Therefore, the context is different, and indeed the oblique definition of iron vs. steel by Japanese nomanclature, shows even more contextual emphasis to the end product rather than a laboratory accuracy of compositions.

 

Just my thoughts toward a casual conversation. Opinion worth what is charged.

[Ford Hallam]

Morning gents,

 

seems to me that the matter was worth delving into after all :D ...

 

Richard, the greater debate I declined to enter into was the classification of tosho and katchushi products based on visual judged, technical criteria. Specifically, the assessment of the metal's composition. As I think I have shown, in my opinion the criteria used are not reliable. It follows, in my mind, that therefore the subsequent hypothesis is unsound. No need for me to debate any further.

 

Guido makes the point that the we ought to concentrate more on the aesthetics of the work, my inclination entirely ... I'd add that the classifications we use should be seen only as useful, but general groupings...and ultimately artificial. I think that, particularly in the earlier periods as Ted has pointed out, we are faced with more regional variation then we probably realise. Attempts to tidy everything up and put things in the correct boxes, are bound to be very subjective. Even the armour maker/sword maker origin is just speculation really... and to be honest I don't buy the idea of swordsmiths knocking out tsuba on their off days from the left overs... but that's a whole other debate

 

I reckon Pete sums it up perfectly ( and Ted seems to me to be of a similar opinion ),

 

It's all steel, just of different carbon concentrations. You have many different tsuba being made by many different makers at many different times in many different locations and you're trying to fit it all under two headings, (Ko) -- Tosho or Katchushi. ....

Bottom line -- get away from using 'Tosho' and 'Katchushi' as a heading for technical data and use it for a stylistic categorization, then sub divide by technique and metal composition as necessary.

 

Personally, I think Pete's "bottom line" has serious merit.

[Martin]

All,

 

this thread is very much worth reading, thank you.

May I just add a question in this context, that has occupied me for quite some time.

 

What factors exactly determine the color of the Patina of an iron (or steel :D ) Tsuba?

Is it the composition of the plate or rather the technique / or fluids used in the patination process?

 

Thanks,

[Ford Hallam]

Hi Martin,

 

the colour we see on tsuba, the patina, is essentially an inert form of rust. In ideal conditions this form of rust has formed what is called a passivation layer. This means it is a non-reactive, protective layer on the steel. The presence of phosphorous in the steel is very important in this respect. This basic film is however pretty much composed of the same iron compounds and is thus the same colour what ever the basic steel composition. The variations in this layer's tone are due to the degree of active rust present...ie; more active corrosion...more reddish rust. The inert layer is quite dark verging on black.

 

having said all that, the tsuba-shi will typically introduce further ingredients into the patina layer. Partly to help create this essential protective coat and partly to make a pleasing colour. Sulphides, copper salts, and organic material such as oil ( which is then made to oxidise and help seal up the pores of the metal) are fairly common additives. A certain amount of heat can also be used to introduce yet more iron oxide compounds in the mix. Think of the rainbow of interference colours you see on a piece of polished steel when it is slowly heated up and you can get an idea of the sort of subtle manipulation that this may offer.

 

Hope this help to shed some light on this arcane art/science

 

regards,

 

Ford