A bit rough but someone has loved it!

[cdrcm12]

Hi,

 

A recent purchase from a UK auction house, along with another tsuba which I may post later. Unfortunately it's a bit corroded except for the seppa dai but I liked the design of waves and Chidori and thought I would 'save' it (didn't pay a lot for both). As for school I'm not too sure, Kyo-Shoami possibly, any help here welcome, I'm sure I've seen this design before? You can still see some of the carving on the waves, in the right light.

 

What's also interesting, as a result of the pitting is what I think is a tekkotsu that has been exposed on the mimi, at 9 o'clock on the second image below and about the same position in the third, is this correct?

 

Dimensions:

Height: 72.5mm
Width: 72.5mm
Mimi thk: 5.5mm
Seppa dai thk: 5.95mm
Nakago ana: 29mm x 9mm

 

As the title of this thread says it's been loved by someone over the years given the number of tagane-ato on the front and back, indicating re-mounting several times.

 

 

Many thanks for any insight, I'll keep working on the TLC!

 

[ROKUJURO]

Colin,

indeed a pleasing design!

What you see as TEKKOTSU is probably something different. TEKKOTSU are small lumps of iron in an inhomogeneous TSUBA steel plate, so this could be something like a broken piece of a stainless blade that cut into the MIMI.

Just guessing, more microscopic photos might reveal another cause.     

[cdrcm12]

Hi Jean,

 

Thanks for the quick response, you are absolutely correct about the tekkotsu, my thought was the corrosion had exposed some form of crystaline structure within the lump but I like your theory of a piece of blade stuck in the mimi from a blow! I'll try get some closer shots of the item, but it does actually look like it would fit the shape of the dings you see in blades.

[cdrcm12]

Here's a couple of closer shots of the item.

 

[kissakai]

Nice close ups

 

[Shugyosha]

I think the motif is breaking waves. Great tekkotsu - I'm sure that with some careful fussing the rust could be neutralised without removing the patina. Some tips here:

 

http://www.japaneseswordindex.com/tsuba/tsubacln.htm

[cdrcm12]

Thanks John and Grev.

 

I'll keep giving it a rub on/with a cotton cloth to try and improve the appearance.

[ROKUJURO]

Colin,

this was a lovely SUKASHI TSUBA and I would really like to see improvements with your treatment! But I have to confess that in my opinion, corrosion has eaten away some of the iron, so I am not too optimistic that you will achieve a much better surface!  

[cdrcm12]

Jean,

I have to agree, when I first received it I thought it had some form of hammer finish! I'll see what I can do, at least it won't get any worse.

 

Still not sure which school it's from?

 

Thanks again.

[ROKUJURO]

Colin,

I think it is a late (possibly 19th century) TSUBA, and in these times styles and schools are difficult to separate from each other. A rounded MIMI, but not looking like true AKASAKA, a WAVE design perhaps inspired by YAGYU,  a bit of a symmetry like OWARI - others may see some KYO SHOAMI traits.

Difficult fo me to pin it down.

[Bugyotsuji]

Saitō Dōzan 斎藤道山 was from Mino just above Owari, and his Mon was the 二頭波 Nitō Nami or two-headed wave.

[cdrcm12]

Thanks Piers.

Found this Saito kamon.

[Bugyotsuji]

Mino was landlocked, but by marrying his beautiful and intelligent daughter to Oda Nobunaga in Owari to the south, his lands extended to the sea at last.

[Ford Hallam]

For what it's worth this is what I see...

 

Despite apparent serious surface corrosion there is the evidence of laminar structure that would inevitably be present in hand wrought pre-industrial steel/iron. This sugests that the tsuba is made from an homogeneous plate of material, my intuition suggests mild steel.

The second point, already implied by my first observation, it that the very evident pock-marked corrosion surface is absent from the inner walls of the sukashi. We also see still crisp edges around the seppa-dai and, for me, unconvincing tapering out of the texture in to the seppa-dai itself.

 

The kozuka atari is a bit too curved too to be a reasonable fit alongside a kozuka back suggesting a lack of awareness of its realy practical function and meaning.

 

My feeling is that this is a modern-ish hobby piece worked up to look older than it really is.

 

 

[Dan tsuba]

Hello all!!

 

So, some have stated that this tsuba is “corroded”.  It is my understanding that corrosion appears as blue or green, depending on the metal. “Rust” appears only on iron objects and appears as reddish or brown.

“Corrosion and rust are often used interchangeably. While corrosion and rust are both a result of oxidation reactions (where an element combines with oxygen), there are differences between the two.

Corrosion impacts a wide range of objects, while rust only impacts iron and its alloys, such as steel. Therefore, rust is a form of corrosion, although it specifically refers to oxidation of metals containing iron.”

So, I believe the term “rust” (over the term “corrosion”) should be applied to this tsuba.  Perhaps a “minor” point.  But definitions are important to correctly describe an object or its “deterioration”.

I am also of the opinion that this piece is an “older” piece (not a “modern-ish hobby piece worked up to look older than it really is” – as stated in the previous post).  It is my opinion that the “rust” shown on this particular piece is authentic and would take a very long time to produce the “pitting” shown on this tsuba.

 

With respect,

Dan

[Spartancrest]

It is an interesting piece - gets people thinking which is always a good thing . I was wondering if the texture was made intentionally? Like an ishime finish - what stands out to me is the seppa-dai is not corroded/rusted or whichever except around the margins. This would seem deliberate or how else to explain the seppa-dai? The texture reminds me of an old iron anchor sitting at the bottom of the ocean for 50 years - but then once again the seppa-dai even with a copper seppa attached would still deteriorate and it hasn't. Maybe the sword was lost in a desert and ended up sandblasted.

[Brian]

Dan,
When you get an opinion from someone as highly regarded as Ford, as perhaps one of the West's foremost authorities on Japanese metalwork, his opinion bears some careful thought, to put it diplomatically.

[Ford Hallam]

thank you Brian, for your endorsement.

 

in case my meaning was unclear due to my typing error;

'Despite apparent serious surface corrosion there is the evidence of laminar structure that would inevitably be present in hand wrought pre-industrial steel/iron.'

ought to read

Despite apparent serious surface corrosion where is the evidence of laminar structure that would inevitably be present in hand wrought pre-industrial steel/iron?

 

Dan,

I'd have to disagree with your suggestion that this is a rusted, not a corroded, piece of material. Corrosion in fact covers the damage caused by rust, and that's really what we're looking at here.

It is perfectly correct to speak technically about a corroded steel structure and to distinguish it from a merely rusted one. Structures made from Corten steel, for example, rely on the formation of a rust coating to protect it from further rust penetration that would lead to corrosion and mechanical failure.

Perhaps a simple and more familiar example might clarify; the patina we admire on ferrous tsuba are composed of rust, albeit in a fine and stable state. Once that stable rust patina is disrupted and 'goes live' it is actively rusting, and causing corrosion, ie; the degradation and breakdown of the metal's surface and eventually structure.

 

As for the time it might take for a surface of steel or iron to exhibit the sort of texture this example shows that would depend entirely on the conditions it was kept in or subjected to. It's perfectly simple to recreate this degree of 'apparent' corrosion in a few months. Quicker if you were to use a little bit of electrical current to speed things up a bit. 

 

And for anyone who really wants to go down the rabbit hole of pre-industrial ferrous metal structure and the effects of time and corrosion etc. these four books are the most frequently thumbed on the subject in my library. There's about 1300 pages of solid material in there.

 

regards all

 

Ford

 

 

IMG_0990.HEIC IMG_0992.HEIC

[Dan tsuba]

Hello all!!

 

Ford, thank you so much for your post and opinions.  Also, thanks for the references that you have included.  I will try to purchase one or two and “learn many new things”.  Hurrah!!

 

I have been advised (from a previous post on this thread) to give any opinion of yours “careful thought”.  But as a part of “academia” I must disagree with you on the fact that corrosion and rust can be used interchangeably. The tsuba in the thread is rusted because it is iron.  Further, it is rusted and has therefore corroded.  If it was not made from iron and had deteriorated, it would be corroded and not rusted.

 

Like I stated in a previous post, a minor point.  But with the previous advice, this point has taken on “new meaning”!

I refer those interested to these few links.  There are many other supporting “links” out there.

 

https://dewwool.com/difference-between-rusting-and-corrosion/

 

https://www.arepa.com/resources/blog/corrosion-vs-rust-what-s-the-difference/#:~:text=Corrosion%20is%20the%20process%20by,of%20iron%20and%20its%20alloys.

 

https://byjus.com/chemistry/difference-between-rust-and-corrosion/

 

With respect,

Dan

[Ford Hallam]

Quote

I must disagree with you on the fact that corrosion and rust can be used interchangeably.

I didn't suggest they were interchangeable at all.

 

Quote

The tsuba in the thread is rusted because it is iron.  Further, it is rusted and has therefore corroded.  If it was not made from iron and had deteriorated, it would be corroded and not rusted.

Nice summation of exactly what I wrote;

"Corrosion in fact covers the damage caused by rust, and that's really what we're looking at here.

It is perfectly correct to speak technically about a corroded steel structure and to distinguish it from a merely rusted one."

 

 

 

Quote

It is my understanding that corrosion appears as blue or green, depending on the metal.

On zinc and lead it'll be white. Silver is reduced to a black silver sulphide, as described below. 

The corrosion products that occur on iron and steels appears in a range of reddish, brown to black colours and is known as rust.

Some of the blue and green corrosion products you refer to do contain some oxygen but those particular compounds are generally more complex than simple copper tin zinc lead alloys and oxygen. Copper chloride is a turquoise colour CuCl2, no oxidation involved.  Copper Nitrate is a good royal blue, if it was only oxygen doing the work the result would be either black or brick red but the nitrogen changes things. Cu(NO₃)₂ 

 

 

Quote

While corrosion and rust are both a result of oxidation reactions ...

Not all corrosion is in fact a result of oxidisation, as described above. Take silver as an example pertinent to tosogu, it's a silver sulphide Ag2S that forms on the surface and gradually consumes it.

I ought to add that the broader topic of corrosion covers much more than only metals and involves many more complex process other than merely oxidisation.

 

The scientific literature on rust lists (at least);

 

12 varieties of Iron oxides and hydroxides

3 varieties of iron carbonates

9 types of Iron chloride

12 Iron sulphates

4 Iron phosphates

and

10 Iron carboxylates and cyanides.

 

 

 

These all have their own particular colours and microscopic structures. The colours range from yellows, ochre, green, a wide range of browns through to red, greys and black.

I believe it's the interplay of various specific 'rusts' like these, in a patina, that results in the characteristic colour and tone of certain Tanko school's tsuba.

 

What has been especially interesting to me is that traditional tsuba patina recipes and those I've developed from the original sources reflect very well almost all of those varied and complex compounds we generally lump under the generic term 'rust'. 

Rust is so so much more than Iron oxides. Stable iron patina are invariably complex and multi layered compound structures  produced by complex and sophisticated process that were developed over many generations through trial and error. If it just looks like crusty red iron oxide the patina is long gone.

 

Well that'll teach me to throw in my tuppence worth... but as chance would have it I was in fact writing on exactly this topic of corrosion and ferrous patina last evening.

 

 

 

 

 

 

 

 

 

[ROKUJURO]

Dan,

 

your first source is not always correct (I won't read it all). I would be critical with the content. 

...It is a slow process   (what is exactly 'slow'?)
Rusting is a type of corrosion    Corrosion includes rusting.  (Correct, please remember that)
Rust is of red, orange color and the end product is flaky in nature (no, that is no complete answer. The appearence of 'rust' may depend on the iron type, and the colour range extends up to black. Iron has three oxides with different colours, and these combine to 'rust'.

I would like to add that corrosion does not occur on ceramics, and corrosion on iron alloys is basically a chemical reaction with oxygen. Water (= moisture) is necessary in the formation of iron oxides ( x Fe{II}O . y  Fe{III}2O3 . z H2O ). 

 

Try to understand what Ford wrote; there is not much to add.

[Ford Hallam]

I've been bothered by this muddying of the waters regarding corrosion and rusting.

 

The actual physical and chemical process whereby iron and steels is converted into any of the corrosion products I listed as 'rusts' in my previous post is called, by real metallurgical scientists, the corrosion process. We can have our own, tsuba/tosogu specific understandings of patina etc. and personally I need to make that distinction sometimes because that's a big part of my own particular work.

 

But : The action on the metal is 'the corrosion process' and the result of this process is 'the corrosion product' or rust. Sometimes this rust can be made into a stable and attractive finish we enjoy as patina.

[Rivkin]

Corrosion or rust, this is not normal patina as it forms even on 500-old piece of iron.

The surface profile versus age is an interesting topic, as in many cases the roughness can increase at first and then decrease.

Here the variation between ups and downs is extreme and everywhere, so there was an exposure to something rather aggressive or at high temperature.

Some areas are flat, they were covered at the moment of exposure.

 

Whether this was intentional or what's the tsuba's actual age is a bit difficult to infer.

[vajo]

Silver can't and didn't rust. Silver did not oxide and it didn't loose any material by oxidation. 

 

 

[ROKUJURO]

Silver can't and does not rust. Silver does not oxide and it does not loose any material by oxidation. 

 

Chris,

 

silver does not rust of course, but it can indeed corrode. It is attacked by H₂S (hydrogen sulfide) which is contained in our atmosphere and takes on a black colour (or patina, if you like).

 

 

 

 

 

 

 

[vajo]

No Jean silver is not attacked. It didn't loose own material. 

 

Thats why it is called precious metal.

 

Not the silver reacts but the electrons with the air (h-sulfide). With a chemical reaction you can sent the electrons back and loose the binding. 

 

Silver and Gold are very strange elements born in a supernova they will exist forever when the universe is long gone.

[Rivkin]

Gentlemen, I am suspecting I am a bit out of my comfortable depth, but:

 

1. Silver is not widely used in electronics industry despite having many advantages in terms of conductivity related metrics over gold: because it oxidizes. With jewelry it is not an issue at all as the layer is very thin and removed by any rubber eraser, but in electronics that would be difficult. In jewelry they indeed use "oxidized silver" which is black silver sulfide rather than silver oxide. This is also a common terror of houses build next to coal power plants or similar industry - copper and silver there has a sulfide problem. Its rather common in the UK apparently, but its not a universal problem.

 

2. Gold does not oxidize but its never used in jewelry as pure metal. Very old gold will loose a bit more gold due to its high plasticity and will become more copper-lead. So yes, with some skill and good color perception you can distinguish old Kofun period's or say Scythian gold because it has content which people typically don't use and their copper base was rather dirty.

Gold is one of the most plastic metals and can actually wear and tear a lot.

[mas4t0]

8 hours ago, vajo said:

No Jean silver is not attacked. It didn't loose own material. 

 

Thats why it is called precious metal.

 

Not the silver reacts but the electrons with the air (h-sulfide). With a chemical reaction you can sent the electrons back and loose the binding. 

 

Silver and Gold are very strange elements born in a supernova they will exist forever when the universe is long gone.

 

Chris,

 

Gold and Silver are not meaningfully different to other atomic nuclei from the perspective of particle physics. Nickel and all subsequent (i.e. higher atomic number) elements were formed via Supernova Nucleosynthesis (or perhaps in the core of Neutron Stars).

 

The atomic nucleus of a stable element will not (ever) decay. Gold and Silver are no different from any other stable element in this regard.

 

There are however unstable isotopes; Gold-198 for instance is a radioactive isotope of Gold which undergoes beta decay to stable Mercury-198 with a half-life of 2.697 days.

 

Additionally, Gold can be Oxidised and fully dissolved in Aqua Regia; Gold can be Oxidised.

 

No atomic nucleus is altered in any chemical reaction; the nuclei are only alerted in radioactive decay, fission and fusion. Chemical reactions only affect chemical bonds and the energy released or absorbed in the reaction is dependent on the difference in enthalpy of the bonds broken and the bonds formed.

 

"When the universe is long gone", whatever that means, it would surely presuppose that the matter and energy would be long gone (including Gold and Silver).

 

From a chemical perspective, oxidation of iron is fully reversible. This is what smelting is all about; extracting a metal from its ore via reduction, but this doesn't help much with regards to an object as the corrosion is permanent and the iron is now elsewhere.

 

Oxidation is, technically speaking, loss of electrons. An atom (or atom group) loses electrons when it is oxidised - conversely, an atom or atom group that gains such electrons is reduced.

 

In inorganic nomenclature, the oxidation state is represented by a Roman numeral placed after the element name inside the parenthesis or as a superscript after the element symbol, e.g. Iron(III) oxide.

 

Combination of both half-reactions is what is termed as a Redox reaction, an electron transfer from one chemical species to another.

 

Gold “does not oxidise” according to our experience because it ranks very high in the so-called electrochemical series (Standard electrode potential), a list of how easy it is to oxidise chemical species.

 

 

As Gold is above oxygen (the commonest oxidiser), no oxidation occurs to it.

 

However, the reaction with Aqua Regia does involve Oxidation of Gold to form Chloroauric acid (HAuCl₄) in solution via the following reaction:

 

Au + HNO₃ + 4HCl ⟶ [AuCl₄]¯ + [H₃O]⁺ + NO + H₂O

[Spartancrest]

    

[vajo]

Mark aqua regia changes only the state of matter. You can turn gold from tetrachlorgold back to gold. You can not destroy gold and silver. 

 

For silver, when you have 1oz of silver and it gets patinated what is the weight of that 1oz silver? When you remove the patination what is the weight of that 1oz silver now?