It's not exaggerating to use language like 'meeting the maker' and 'died and gone to heaven', honest. When this early twentieth century Japanese cigarette case was shown to me, I had to work on it. It isn't made by anyone special - it's not even a known maker's mark on the back - and the execution of the technique isn't spectacular. It's a nice piece, but as far as I'm aware, there's nothing out of the ordinary about it. They were made in numbers for export out of Japan in the late 1800s to early 1900s. So what makes it so special? For me, the moment that sends shivers down the spine, is when I'm hunched over a microscope, the image is blurred, and with the twist of a knob, the surface comes into sharp clarity. Behind the great orange craters of corrosion, looking suddenly as rough as the surface of Mars, deliberate marks were lurking. These marks were left by the hand of the unknown maker, around a century ago. He probably made hundreds of these cigarette cases in his long apprenticeship, kneeling at his low workbench, with the small hammer of the nunome-zogan craftsmen pinging up and down in his hand. Nunome-zogan, 'cloth weave' or 'fabric' inlay, is so called because of the textured surface onto which the thin sheet is pressed. These marks on the surface were visible to me only because the corrosion had pushed away some of the inlaid silver sheet as it had expanded, and eventually the sheet had pinged off and become lost. Finding these marks under a microscope is akin to seeing the thumbprint of a sculptor in a statue.

This is the condition it came to me in. As an object, it's fairly 'unreadable': Mount Fuji is recognisable in the background, and the roof of the house and the branches of a tree are discernible, but the rest of it is too hidden behind the creeping patches of iron corrosion to tell what the shapes are with much certainty.

Where do you start with an object like this? Much of this kind of work was made for export, and America and England were two of the largest consumers of these often lacquered objects. It was examined under UV light, because lacquer will fluoresce anywhere from a lurid orange to a murky brown depending on its age under such conditions. It didn't fluoresce at all on the outside, indicating that the black I was seeing was just oxidised iron, magnetite. This layer is considered pretty stable, and was as close to the original surface as I was going to get, so it was decided to try and leave it in tact as much as possible. The next issue, having determined the absence of coatings, was to decide how to treat the corrosion. The precious metal foils are extremely thin, typically around 0.02mm, so any rough abrasive treatment would just have lifted them off, or worn them away! A gentle brush over with a very fine and light wire wool (0000 grade) removed the loosest corrosion, and avoiding the inlays meant that they were not in too much danger.

However, that did not remove all the corrosion, and peering down the microscope under x2 magnification, I saw this:

Removal of the corrosion under the microscope with a scalpel took a long time, but it was worth it, and done without a microscope, it could have done a lot of damage. The hardest parts were where the iron corrosion had migrated through the thin precious metal areas, and this was some of the most delicate work I've had to do to date as a student at West Dean.

The hatching of the surface is frequently called "damascene" work in the west, and as I understand it, this kind of Japanese nunome-zogan work, on objects like this, is often called "Komai style", because the Komai family were prominent metalsmiths in Tokyo operating in the late nineteenth century. This cigarette case is not Komai work, but the demand for that style produced a lot of similar work at the time. It was an honour to be able to explore its surfaces under a microscope and reveal little details. I'll never know a surface as well as I know this one, I think!

As I began to explore the surface, millimetre by millimetre, gradually and gently picking off the areas of raised corrosion, details began to emerge, such as the torii, the iconic gateway to the Shinto temples, the sails of the boats - didn't even realise they were boats at first! - and the elliptical shapes were revealed to be both copper and silver, while I had thought they were just silver before working on it.

With the raised iron corrosion gently picked off, the surface was degreased, and then 10% tannic acid was applied to the surface. This isn't appropriate for all objects, but since it turns the surface black, converting the corrosion products into more stable iron tannates, it was deemed an acceptable change to the surface in this case. Tannic acid also has a bluish hue to it, which I was desperate not to be able to see after I'd finished the treatment, so each time a coat was applied, it was gently blended back with fine wire wool to remove the blueish bloom that forms when it dries.

Once the oxides had been converted, and the telltale redness of the iron oxides had reduced, even under the microscope, it was given a clear coat with microcrystalline wax to protect it. This means that for now, the object is protected and will not deteriorate further. More work will be done on it shortly to ensure the inlay does not part company with the iron, which will involve removing the protective wax again from areas where I need to work (the central torii with the triangle missing), and using a copper 'pusher' and then a bamboo one, I will gently press the foil back into the grooves beneath. Hopefully, no adhesive will be needed, but if necessary, I will re-adhere the original foil to the surface with an adhesive like Paraloid B72.

My masters thesis is on the conservation of wire inlay (sen-zogan, rather than nunome-zogan, which this is), and with Japan's rich tradition in the technique and its variations, I have in the past six months or so developed a real interest in Japanese objects and artistic techniques. I recently had the very great pleasure and privilege of joining Ford Hallam for a day on one of his major projects in London, and got to see some of the V&A's stunning collection of Japanese metalwork (mainly kozuka (the hilt/handle for the little blades, called kogatana), and tsuba (sword guards), and some samples of alloys made in Tokyo and exported to the west for study and analysis. My masters project has involved making my own inlay chisels and doing my own test samples of wire inlay to corrode and then treat, so getting to work on this inlaid cigarette case was a real treat. I got to see how a (slightly different) technique of inlay is done, almost first hand, from the hands of the man who made it, only it was a century later…