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  • Cast tsuba

    My thoughts on all this were started by the problem of making sukashi tsuba. All modern tsuba makers cut them from solid iron using a piercing saw, something the Japanese did not have. What they could do was make short cuts in iron using a wire and abrasive to make what we call ito-sukashi but you could not cut out something like an akasaka tsuba that way - it would take forever to do. Looking at the tools they did have we find drills, scrapers, chisels and files. I do a lot of metalwork and I know how hard it is to make shaped holes with tools like these - especiall thin bars which bend away from the tool as you chisel it.. You also have to remember that many of these tsuba makers, especially the machi tsubashi, had to earn a living to eat. They could not afford to make only one or two tsuba a year. Craftsmen the world over find the easiest way of doing things, so we should examine the technology they had and see how it could be used to produce tsuba efficiently. Note: I am not saying all tsuba were made this way but I think many or most were.

    .

    The clue to all this lies with kettle-makers and the quotation from a famous spearman (I cannot remember the detais now but essentially it was this) who advised a pupil to put tsuba in a rice mortar and pound them. Those that did not break were good ones to use. Now a rice mortar is made of wood so how could a forged iron tsuba break if hit by wood? It might bend but it would not break. We know kettles are made from cast iron, iron with 3% or more of carbon, that is quite hard and very brittle under tension but strong under compression. Depending on the exact process, the product when cast is known as grey or white cast iron, the latter being very hard and cannot be filed or chiselled. When a cast iron item is packed in a crucible with iron oxide (fire scale from hammering red hot iron or even high quality iron ore) and heated for hours in a furnace, the oxygen in the iron oxide reacts with carbon in the surface of the cast iron and reduces the carbon content. See 'Iron and Steel in Ancient China' by Donald B Wagner p. 356 where he describes how cast objects were heated in crucibles with iron oxide to make malleable tools and weapons in ancient China. We know the Japanese used this process, called decarburisation, to convert the surface of the kettles to a softer malleable material that can be chiselled and carved. Making a tsuba then would involve making a clay mould from a wood or metal pattern and then casting it in iron. At this stage it would probably not have much detail and because of shrinkage when metals solidify it will be oversized. Once cast it would then be decarbourised. If this was not done properly, or for long enough, the inside of the metal will still contain too much carbon and still be brittle and hard. By heating for a long time, the carbon from inside migrates to the surface and is burnt off so it was important make sure this happened. When finished, the product was soft and no longer brittle and could be chiselled and filed to finish the details. All the tsuba maker needed to do was smooth the surface with scrapers and do any chiselling and polishing to produce a finished tsuba. One little clue that this is how they were made is what the tsuba collectors call 'bones'. These are hard parts that reveal themselves, especially along the edge when it had become worn. These I believe are little inclusions of harder metal where the decarbourising has been incomplete. You also see the odd tsuba where some part has broken off. Again I think this is because the decarburisation was rushed and left some parts with too much carbon in it.



    Now to soft metal tsuba. Why would someone cast a thick piece of shakudo or shibuichi and then chisel half of it away to get a raised part? Why not just cast it with the design in relief already there? I know Ford Hallam casts a button of metal and hammers it down to thickness and then inlays a lump to carve. A lot of work and no doubt it was done for very high quality work, but for low quality tsuba it would be too much work for the price of the finished tsuba.No I am sure they were cast and then simply finished with scrapers and chisels. Always remember these guys had to make enough to keep their families in food.

    Ian Bottomley
    Ian Bottomley - UK

  • #2
    This was an interesting read, Ian. Thank you. A few years ago I posted a -shaped tsuba over on the NMB where someone suggested that it could have been cast. This set off a storm of protest that none were ever cast, and I was so embarrassed that I ended up giving the tsuba away.
    Piers D - Japan / UK

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    • #3
      To second Piers, I also enjoyed reading your thoughts Ian! Relying on metallurgy knowledge seems like a good way to counter such rants as Piers experienced.
      David Mueller - Germany

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      • #4
        Good Evening Katchu Bunnies.,

        Thought provoking as always.

        I can remember reading something about cast "spokes" being inserted into Saotome Kiku Tsuba to save time.

        Also regarding Ito Sukashi in Iron, I was once told by a chap at Bonhams that the cuts were really wide and then hammered to the perfect width using some kind of insertable metal former.

        But he did have a gammy leg and a metal plate in his head from some altercation of the Military type.

        Pip Pip Cheerio

        Malcolm

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        • #5
          Malcolm, Yes, ito sukashi was done using an abrasive on a soft metal wire stretched on a frame to keep it taught. When it is cut the metal is hammered down to narrow the gap with a bit of metal in the gap to keep it uniform. You will notice that these cuts rarely exceed 2 or 3cm and that even then probably took quite a while to make.

          Piers, I remember your post on that tsuba - there was discussion about it being the kanji for hi, or a leaf of some kind. Since then I have seen at least two others on Yahoo. Obviously a standard pattern from some workshop. I have suggested all this about decarburising before on NMB and like you received howls of protest. I kept asking if not done using a piercing saw, how were they done - but answers came there not! I suppose the idea of a guy sat in a shed filing and chiselling his little tabi off for months is the romantic ideal tsuba collectors wish to preserve. What they forget is they collect these objects for the consummate skill and artistry that goes into them. In reality it is immaterial how long they took to make.
          Ian Bottomley
          Ian Bottomley - UK

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          • #6
            Bang on Ian,

            Let's draw a parallel with 18th and 19th century English Silversmiths Hester Bateman or Nathaniel Mills.

            More than a few modern Collectors believe that poor old Ricket legged Nathaniel and tragic Fantine like Hester were tapping away by failing candle light and eyesight in some scrofulous garret until age and infirmity took them to the Workhouse.

            Rather than, as with the General Staff in the first World War and the likes of Damien Hirst and Jeff Koons today, they were thirty miles away from the front line of creative operations, quaffing Crystal like there was no tomorrow.

            They had businesses to run and deadlines had to be met, no different to the Kinai of Echizen or the Heianjo craftsmen.

            I once had a Dent Admiralty Wall Clock which was quite an aesthetic and technical tour de force, requiring some in depth research before I could "reluctantly" part with it........

            In the Archive of the Worshipful Company of Clock Makers, half buried in the depths of London's Guildhall, I was given the workbooks of Dent and company for the year and clock in question and found the most meticulous accounting of all the various artisans responsible for the parts and parcel of the clock, right down to the farthing for the welding of a fusee chain.

            It would be fun to find if there was a Japanese equivalent in the form of workbooks with prices etc.
            Pip Pip Cheerio

            Malcolm

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            • #7
              A friend of mine living in Japan has been visiting former locations of where katchushi operated. He has found nothing. It seems that after the abolshment of the samurai that they simply packed up shop or diverted to making other things. As we know the japanese are kings of recycling, maybe the papers ended up as lacquered umbrellas.
              David Thatcher
              Professional Armour Restoration (Katchushi Koubou)
              Web: http://www.yoroi.uk
              Facebook Group:
              https://www.facebook.com/groups/Samuraiarmour/
              Instagram: https://www.instagram.com/raimu_gallery_uk/

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              • #8
                Or consigned to the flames. My wife emptied out an old Katana box full of paperwork and set fire to the pile, as if in an act of purification, I guess. So's we can all go back to a state of innocence and start afresh?
                Piers D - Japan / UK

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                • #9
                  Cheers D & P.,

                  Just found some interesting info....

                  In the 16th Century, there was a Guild (Za) of Paper recyclers lead by two families, the Togai and the Osaji.

                  The Togai - Za handled top end material, and the Osaji - Za handled the lesser materials.

                  They both had close ties with the Imperial Library, which regularly recycled items in its collection.

                  The term "Shukushi" was applied to papers that had been recycled by dissolving the fibres in water.

                  It seems the residue ink left a grey tone which, if then recycled yet again produced a darker tone of paper and so on

                  Here's the meat of the article:

                  https://books.google.co.jp/books?id=...0paper&f=false.

                  Later on the term Kamiya - gami (Paper-shop paper) was commonly used for recycled papers.

                  Similar to the western Palimpsest, where an old document was scraped or washed to be used again.

                  Pip Pip Cheerio

                  Malcolm

                  Comment


                  • #10
                    Malcolm, An amazing find about paper - how do you do it? Your story about Dent clocks is paralleled by one about small-swords in Georgian England. A colleague at the armouries found a receipt / pattern book in Birmingham library compiled by a cutler who essentially farmed out all the various jobs - his contribution being to assemble the pieces into the final sword. The same was true in the Brum gun trade. One family made barrels, another locks and so on. I had a Birmingham percussion pistol with an inscribed name and street address. From the trade directories of the period it turned out the guy was a butcher who had obviously financed the making of a few guns as a way of making a bit of profit from a bit of spare capital. I still have another pistol, proofed in London, inscribed 'Roper, Halifax' (my home town). Interestingly the engraving on the side with the name is different from the other. Roper was in fact an ironmonger who was obviously buying pistols from London with one side left blank and adding his name to them.
                    Ian Bottomley
                    Ian Bottomley - UK

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                    • #11
                      OCD............

                      Here's some more about it from a different source:

                      http://komonjo.princeton.edu/

                      Last edited by Malcolm; 11-04-2017, 10:35 PM.
                      Pip Pip Cheerio

                      Malcolm

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