Cultural assets at AKITA prefecture, Kozuka by Shoami-Denbei
5th Feb. 1963 Reserved
12th May 2003



“Mokume-gane” is a special metal working technique that Japan boasts to the world. The special process reaches even to a thought and mental area of conversation of the material nad those who produce exceeding the frame of mere technique. This time, I focus to the process of patterned making, and tried a complete restoration of Dewa akita ju Shoami Denbei’s kozuka which is an example of the oldest Mokume-gane and which also the most graceful Mokume-gane in Japan. This research becomes the first restoration research on the pattern of Mokume-gane technique as long as I know. I thought that it is the only way of concretely clarify an advanced technique of craftsman at that time, and acquire the technique learning their thought and spirit.


Mokume-gane also called Mokume-copper, and at first, it starts from accumulating the board material of the different colored metals, over and over again.It is a technique that after the surface is carved down with the tools like drill and tagane, forged it with the hammer to flatten it out for showing the pattern like “woods eye”on the surface.And also, Mokume-gane called TAGAYA-SAN pattern which is called from a precious wood of Chinese tree, from those Mokume pattern, and also called KASUMI-UCHI.

It is told that the origin starts from the ‘s work of GURIBORI. It is general that it was influenced from Ainu’s race pattern, or it was influenced from the chinese GURI made from the lacquer. GURI is the generic name such of tea-things which carved GURI-pattern, made by the technique of the lacquer such as SEIHI created at the Song through the Ming dynasty. It was imported in Japan around the Muromachi era and it was treasured that was able to read from the record of the tea party. And also it is famous that the GURI is the origin of the Kamakura-bori. There are several great goods of the GURI-pattern of KOUGOU made from the lacquer, which was made by the age of South Song are stored at the Museun of the Tokyo University of Arts and Fujita Art Museum in Osaka.

In the later age of Edo period, there were some masterpice remaining such as Inro, which were made by the lacquer of the domestic production that was observed with the same orinin. And also, in that age, this kind of design was widely penetrated as the luxury goods. The technique of Mokume-gane was completed at Tenpo period which was the later period of the Edo period, and there was GURIBORI expert appered who was the pupil of the Akao Yoshitsugu 7th and Tashichi, his name is Takahashi Ubeimasatsugu. The feature carving is sharp and deep. Afterwards, the Shoji’s pupil Okitsugu who was also the expart of an author of Mokume-gane appeared, too. The sword equipment of a splendid GURIBORI and Mokume-gane in existence by the Takahashi sect who starts from Shoji and Okitsugu Takahashi might be suitable for the idea as the completion of Mokume-gane. The completion of Mokume-gane tequnique was a birth of a new,


In this reserch, I tried to reproduce of this peculiar unparalleled pattern, and I also focused to the concrete clarification of an advanced technique of Mokumegane by craftsman at that time. From the observation of the pattern which above-mentiond, it make a clear distinction from the model of Mokume-gane of the Takahashi sect in the Edo latter period and the simplification stratified patterned Mokume-gane at the age of later period of Edo period through Meiji era, and it can observe that pattern is a peculiar pattern to unparalleled by Dewa akita ju Shoami-Denbei.


At first, the fixation of the number of the accumulating and the order of the accumulation are needed. This time, the method of tracing the pattern from the expanded photograph was adopted. Classifies a pattern minutely until it reaches into the details, and ettles the kinds of metals. It originates in the production process of Mokume-gane, but the details of the pattern are an extremely sensitive. It was very difficulut to distinct, because of that the pattern was not made by artificial, and then the complicated changes like contour line of the map were developed complicatedly also in inside of the range of 1m?. There were many parts that were not able to be distinguished partially, and so this time, I selected the part where the difference of the material was extractive clearly, and analyzed.

Abave- mentiond, Mokume-gane is the technique that is carved the accumulated metals with tools like the drill and tagane, and then forged processing by the hummer to make it smooth to puts out the pattern like the grain of wood. From this process, it is going to be a same acumulating order of the metal which constitute of the erelemt of pattern, even if it extracts whichever part of the pattern appers on the surface.



A:shakudo, gold, (copper), gold, shakudo, copper, silver, shakudo, copper, gold, shakudo, copper, silver, shakudo, A copper.
B:A copper, gold, shakudo, (copper), shakudo, gold ,copper, shakudo, silver, copper, shakudo, gold, copper, shakudo, silver, copper, shakudo, B(gold), shakudo, copper.
C:B gold, (copper), B gold, shakudo, copper, silver, shakudo, copper, gold, shakudo, C copper.
D:C copper, silver, shakudo, copper, gold, shakudo, (copper).
*This time, the part where the difference of the material was extractive was selected, and then did the trace analyisis.
*This time, the part where the difference of the material was extractive was selected, and then did the trace analyisis.
a copper, ba copper, b gold, c coper are same layer.

From the trace analysis, it turned out to reverse the accumulatin order obviously, on the boundary of the part A and partB(copper) of the pattern. And it was not only the simple reversal of the accumulating order, but also it can be confirmed that the same accumulating was appered at the upper and under of the copper which displayed before,from a observetion of the traced drawing from a contour line viewpoint.

From this result, it is thought that some kind of special processings to which the accumulating order was partially reversed, were given while in the state of the accumulating before the pattern had produced. In addition, accumulating was reversed similarly on the boundary of copper when observing part C and part B, and in addition, it was able to be confirmed that it was same order of accumulating as part A. From this result, the reversal of the order of accumulating is assumed to be done with a certain rule. In additin to analyze more in detail, it was clarified that the reversal of the order of accumulating was to be done alternately on the boundary of the part of steam lined Mokume-gane pattern which peculair to Dewa akita ju Shoami -Denbei./p>


The order of accumulating of Mokume-gane of Kozuka by Shoami-Denbei’s is 16 layers and these were fixed of copper, shakudo, gold, copper, shakudo, silver, copper, shakudo, gold, copper, shakudo, silver, copper, shakudo, gold, and copper. From the special reversal of the order of accumulating, it is surmisable such as the complex process of which forged to the corner cylindr shape after accumulate the 16 metals, and then, adding the twist processing.To forge the material which added the twist processing into the flat with using a hammer, there is the twisted patern of which becomes the origin of the pattern of Denbei’s peculiar steam lined Mokume-gane pattern appeared on the surface.In addition, carves partially with the tools like drill and TAGANE, then repeat doing the forged processing with hummer until flat and smooth.By this process, it was presumes that a ripple of the roughly concentric circle pattern was appeared, and the twisted pattern was distorted by the influence from that, then changed into the pattern of steam line.


1.Preparation for material

Those materials whichi I used this time, were chosen in consideration of the processing, it was assumed that K20 gold and 970 silver were used so that hardness might steady based on the pure copper.
It worried very much because of the decision of the size of the board material. If it is simple thing which carving accumualting with the tools like the drill and TAGANE, and it does humbly by forged processing., likeTakahashi sect’s Mokume-gane, it is possible to make a bigger size of Mokume pattern, so it is able to cut out the only a necessary part. But, the Mokume-gane of Dewa akita ju Shoami Denbei’s is impossible to make it bigger and cut it out because of the twist processing may add. So the size of the accumulating stage to decide the final finish size. It was clear for the area of surface, but this time, for the thickness, it was guessed from the pattern and decided. The depth of the carving of the ripple of the roughly concentric circle pattern was the standard for the guess. To be able to do the height difference too much in accumulating with the thickness, and to influence externals and streamlined pattern remarkably, so it was judged that the size of the thickness of Mokume-gane of finish is a very thin board material. Finally, it was assumed that it adjusted it at the stage forged to tabular while confirming the state of the pattern when the carving lowering was processed.

From the expectation size of completion and based on the law of mass preservation, and also speculat to the removal of the imperfect part at the edge after accumulation and the compression that add when the material is processed to a flat board material by using a hammer, then decided to product from the 7mm to 8mm accumurated corner stick. It is impossible to be settled at dimensions closely, because in character of Mokume-gane, there are many parts to depend on perception and the experience of a producer from the atmosphere of the pattern and the state of the laminating of matterial at that time, and also a difference of a few processes are making the influence to the pattern. I did a simulation many times by using the corner stick of copper before making actually. But above mentioned, in an acutual accumulation, it is forced to the flexible correspondence for the change of the material from various factors. Therefore, a final decision is a done only on work. On this technology, there is the situation continues that cannnot help to correspond flexibly at the very last moment. This time, all of the compression and extention processing are done by using the hammer, so it is possibole to adjust the rate of the extention for the vertical and horizontal direction. The corner stick selected the balance that was suited to do twist processing and estimate from the volume of the flat plate of finish.

2.Joint of accumulating

At first I polish the each materials with #600, #800, #1000, #1200, #1500 of sandpapers which I prepared in turn, then after that, finished the surface uniformly politely using together with the charcoal polish. After that, repeat them in the turn of analyzed, then heat them then gave the forge welding processing. Mokume-gane is hard to be understood precisely by lack of information and complexity of the process and tends it to be told with welding or bonding, but closely, it is right of the expression of diffusion combination. When approaching the surface of metals for an atom level then give pressure,it makes a metalic bond happen. For a principle, it is possible to join two metalsv for coherence each other. Mokume-gane is the technique which based on the principle of diffusion combination, to conenect the different colored metals as a state of solid-phase body, with the means of heating, pressurizationIn brief, it is not a method of dissolving the metals for connect, but also the method of connecting in a solid state of metals. This technology is applied to production such as a drive part of cars widely industrially. Mokumegane is special metal processing technique which using this principal to be enabled by realizing combination to bear if it create a pattern without losing each metal original hue. After inspect the details and removed the incomplete part of laminating, give the forging process in the sape of a corner stick of 7mm from 8mm with a hammer.

3.Twist processing

By the trace analysis, the twist processing turns out four in total, reversals of the table, the back, the table, and the back. To give the heating and annealing over and over carefully about the order of accumulating, for making the 4 times reversal which mentioned above had happened th the forged molded corner stick. Then, give it to the twist processing carefully, little by little. Afterwards, forged molding was done to the corner cylinder shape again.

4.Carving lowering processing of pattern

Above-mentioned, when the detail of the pattern was observed, it was able to be confirmed that more than half of the number of sheets of accumulating of the metals among the 16 layers, were the constitution elements ot the ripped patern. This means, after the twist processing was added, carving the depth of more than half of accumulating with the tools like the drill and tagane. To carve for the depth by this, at the accumulating with the thickness, it makes big influence on the external form of total and the pattern which was made by the twist prosessing, by the difference of the pitch when it was hitted with the hammer for makes it for flat. Accutually, it was not carving at once. The pattern was made from the twist processed corner stick which was processed to some extent to the flat boarded, which was done the processing of the carving and striking repeatedly over dozens of times. This time, the corner stick material that gave the twist processing was forged using the hammer until the thickness becoming a below about the half. On that process, originally, Mokume-gane is the technology that is not able to produce the same original pattern. But this time I worked very carefully and politely to bring it close to Kozuka by Shoami-Denbei’s as much as possible while using a loupe to confirming the depth of the carving of the drill and tagane. It makes a change for the pattern if using the kind of cutting tool such as file. So this time, I used the hammer until the very end of the completion, to make the surface uniformity, then it was assumed to finish which measered the timing for the pattern may become smooth when reaching the finished size.


This time I used the solution for coloring which consists form 3g of the copper sulfate, 3g of copper green rust, and a little of alum by the 1? of water which used in Tokyo University of Arts.c:B gold, (copper), B gold, shakudo, copper, silver, shakudo, copper, gold, shakudo, C copper. To fat removeing with baking soda, then puts the grated radish on, and puts it into the boiling solution for coloring. To check the color state, it is repeated to take it out and rub the surface with baking soda lightly, and puts the grated radish on, then take it into the liquid. To fine-tune the medicine by the color, it stews finally for about 20minutes, and it is colored. It quickly takes out in the liquid when becoming a good color, and it soaks it in to the water. Puts the beeswax on the surface for protection and for putting out gloss, then it complets.


To finish the restoration production of the Kozuka by Shoami-Denbei which was told that oldest Mokume-gane in Japan, and also the most gracefule Mokume-gane, I anwe felt that depth of this special metalworking technology that Japan boasts to the world. In this restoration, it was not only the restoration of the pattern of the oldest Mokume-gane of Dewa akita ju Shoami Denbei with my body, by restore and experiment of the working process in that age. While researching the Kozuka by Shoami-Denbei in this time, I keenly felt the difficulty of the hand-down and reserching of this specal metalworking technology, Mokume-gane. Mastering Mokumegane is very difficult, because of the complexity of the process in the details, and the vaguly from the oral instruction, and also, this techology is on the assumption that has the basic technique that both of chasing and forging. Moreover, many of the processes are gathered at the stage when the material is made. And this technology is that the each producer have to study indispensable to sublime as a piece of work. Therefore, in the realities as for the guidance of the junior, it stays in experienced production, and it is hard to become a correct tradition. There are uncertainty in this technique which makes a big change even from the small difference that the tool and facilities to use by each author. Therefore, most of all are tossed by the technique of the present, so there are staying the acquisition of the technique superficially.

In a book titled; “Say of material-through Mokume-gane fabrication”, late professor Ito mentions about the spirituality of Mokume-gane. It is very difficult to seek the spirituality of metallic art in the modern society, since the standard of the aesthetic value is not based on the actual lifestyle due to the diversity of art.Mokume-gane shows its natural pattern only when the creator is able to establish a spiritual relationship with the material and iteract with it, using creator’s five senses. However, I feel that to understand the spiritual meaning that lies deep inside Mokume-gane is very hard even for those who are acquainted with art. It is such a shame that spiritual meaning is understated, but instead Mokume-gane’s rare and special pattern is more admired.

Now, I am working on the production of the engagement and the wedding ring, the production of all kind of jewelry, and the art craft goods by using the Mokume-gane technology. I will like to seek the way how users can appreciate and enjoy Mokume-gane along with the spiritual meaning in the modern world, and will like to continue this special metallic technique that Japan boasts to the world.

  • *The translation of book name is temporary as the name is only Japanese.
  • 「History of Tsuba」 Ichitaro Torigoe Nippon Bunkyo Publisher 1965
  • 「Beautyu of Tsuba」 Susumu Kashima Otsuka Kougei Company 1970
  • 「General Survey for Tsuba」 Ayumu Kawaguchi Nanzhin Company 1935
  • 「Study of Sword smith and Tsuba-sumith at Akita Prefecture 」 Tsurutarou and Mihoko Sugawara 1979
  • 「History of Japanese Technology」Asahi Shimbun Company Edited by Toshihiko Ban
  • 「What material has to say -through Mokume-gane works-」 Iori Ito
  • 「World of Tool for Sado 10 Kougou」 Iwao Ikeda Tanko Company 2000
  • 「Tangible Cultural Properties at Akita Prefecture」 A Board of Education at Akita Prefecture
  • 「Technique for Carving and Hammering of metal I ・II 」Editorial Committee of Association for Metal Smith
  • 「Series of Art Manual Jewelry Craft of Metal – Keep Traditional Technique-」Noriko Takada and Minoru Miki Art Publisher Company 1982
  • 「History of Japanese Technology Metal Hammering Yasuo Mitsui」Asahi Shimbun Company 1962
  • 「Report No 105 Survey of Cultural Assets at Akita Prefecture Crafts Skill at Akita Mokumegane Shigeru Fujiwara」A Board of Education at Akita Prefecture 1983
  • 「1998 Seminar Metal Craft at Akita Prefecture」Akarenga-Kan Museum at AKita City
  • 1999「Knife Magazine」World Photo Press

Copyright(C) 2003-2005 Masaki Takahashi All Right Reserved.