Colouring metals in the Far East

By Agnese Benzonelli

How far can someone go in the name of research? In my case quite a long way. For a month, I loosely taped tiny plates of metal to my hands and woke up every morning with green stains on them. I was investigating craft recipes employed in the far East since the fourteenth Century to create coloured metal and alloys used for beautiful small artefacts. Whereas Western taste preferred the natural colour and the polished lustre of metals, the Eastern preference was to use the process of chemical patination, where different chemicals react with the surface of copper and copper alloys to form new coloured compounds.

Fig.1: Left: a tsuba (handguard of Japanese sword) made of shakudo and gold; BM-TS244. Right: a Chinese gu-tong box; BM-1992,1109.2. Photos made by A. Benzonelli.

The Japanese created a whole class of coloured alloys, called irogane. They added small amounts of different elements to the copper and simmered it in a solution containing copper salts, alum, vinegar and other ingredients, to form coloured patinas on the surface. The most beautiful patina, shakudo, was made with copper and gold and achieved a deep blue-black colour. Combining a variety of alloy compositions and solution ingredients, they were able to create hues ranging from pale brown to black. Inlaying different irogane, gold, silver, and lacquers, they were able to create small artefacts and swords fittings with complex and visually impressive designs and patterns.

Fig.2: Picture of the 13 Japanese solutions created and tested taken from Japanese recipes reported in Eastern books.

Later on, Chinese craftspeople imported the technique from Japan, possibly through travellers or trying to copy the Japanese artefacts, and, from the Ming period (1368-1644), they used it to colour ink or tobacco boxes. In contrast to the Japanese irogane, the Chinese would patinate a gold-silver alloy only, which resulted in a dark colour similar to that of shakudo, which they called gu-tong. In both cases, the precious metal content was 1-3%, a larger amount would not affect the final patina colour.

There’s not a lot known about the two different recipes the Chinese craftsmen employed to produce their patinas. However, we do know that one process they utilised was similar to that used by the Japanese to produce the irogane,butwe have no precise recipes for the solutions. Another involved handling the metal until the perspiration from their hands corroded the surface.

Creating and play with metal colours has always fascinated me. Why using gold and silver to achieve that dark colour, instead of cheaper alternatives? What was the role of the different ingredients used in the recipes? Could sweat really be used as a patinating solution? Why did Japanese recipes tell not add precious metals to bronze (copper alloyed with tin) but only to pure copper? Could it be confirmed through scientific analysis that the technology was really transmitted from the Japanese to the Chinese culture? To find answers, I needed to conduct a systematic experimental research which could explain the reasons behind the technological choices of Japanese and Chinese craftsmen.

 I reproduced a series of alloys with tin, gold and silver, which I then patinated, following the recipes for shakudo and gu-tong from available texts. These are not numerous, as the recipes were mainly kept as secret and passed from father to son. We have city records, information sheets given by dealers and, in Japan, technical texts on metal working. I analysed the resulting patinas with techniques borrowed from modern material science, and used the experimental data as reference for the interpretation of historical patinated artefacts in museum collections.

I found that, for both the Japanese and Chinese recipes, the presence of gold in the alloy did, in fact, change the colour of the final patinas, which resulted in a better, more uniform and darker hue. I also noted how parameters such as the fine grade of surface polishing prior to the patination, the use of tin-free alloys, the selection of copper acetate as a main ingredient and the addition of vinegar are all processes and actions that led to a reduced patina growth. And as it turned out, sweat was indeed an effective patinating solution in the Chinese patination (as it can be noticed by the green corrosion products left on the hands), but the presence of gold in the alloy composition is nonetheless essential to obtain a dark hue, not achieved in gold-free alloys. Sweat is a slightly acidic solution, similar to that of used by Japanese craftsmen, essential to create a coloured copper oxide on the surface in just 48 hours of handling. Similarly, in both technologies cleaning of the alloy before or after the procedure suggested in Japanese texts and the abrasive action of the hands in the Chinese method are both similar and crucial steps in the patination process. I concluded from these findings that a dark patina was not the only feature that the craftsmen of both cultures had been striving for. They also seemed to be after a shiny appearance, given by the metallic lustre coming from the alloy.

Fig. 3: Alloys of different compositions patinated with Chinese patination.

In combining experimental and historical observations I gained an understanding of the intentions behind the technological choices made by the Japanese and Chinese artisans. My analysis confirmed the deliberate nature of these choices made to achieve dark and shiny blue-black colours otherwise impossible. This confirmed the importance of colour as a driver of these artisanal processes, and supports the idea that the knowledge was transmitted between the two cultures.

Was it worth in the end – the green hands and other discomforts suffered in the name of research? It was the first study to provide a scientific basis to our knowledge of the methods and choices made by those people, the ingredients they employed in making dark patinated artefacts, and contributed to our pool of knowledge of the artisanal methods and practices described in historical sources. So yes, it definitely was, and I would definitively do it again.

Eating Through the Seasons: Food Education in Japan

By Alexis Agliano Sanborn

Children participate in food education lesson. Credit: Nourishing Japan

Seasons have been celebrated in Japanese society for centuries through poetry and prose. During the Edo-period (1603-1868) this appreciation of nature codified in the creation of the saijiki, or, poetic seasonal almanacs. These almanacs, notes Columbia University Professor Haruno Shirane, “systematically categorize almost all aspects of nature and much of human activity by the cycle of the four seasons.” Without a doubt, food and food production are important seasonal markers.

In the modern era this appreciation of seasonality continues in new forms. Food knowledge has come to be combined with lessons of hygiene, food safety, food production, cultivation of healthy diets, and other teachings through food education, or shokuiku. Food education became law in 2005 which outlined the goals and provisions for local and national support of activities to foster an understanding of a healthy diet and appreciation of food and food production.

One of the biggest beneficiaries of food education are children, who learn about food and diet through classes and hands-on experiences in and out of school. One of the primary ways they learn about food is through their daily school lunch. School lunches use local and seasonal ingredients and serve as a way for children to taste and understand where food comes from, how it is produced, and how the food and themselves are connected to the environment.

Caption: A farmer who contributes to school lunch harvests cabbage in the field. Credit: Nourishing Japan

Food education as taught in schools almost serves as a de facto culinary saijiki. Children come to remember the seasonal or even monthly association to a certain food. The loquats of early to mid-summer will give way to the eggplants and figs of late summer. The month of March almost always include the na-no-hana, the edible rape blossom with a mustard-like taste that is often cooked into rice as part of the daily meal. The month of October is characterized by chestnuts, sweet potato harvests and wild boar. Eating according to the season – shun – has a long history in Japan, but one that is in danger of being lost as diets change and evolve in a globalized world.  Even if cantaloupes may now be available in the grocery store year round, children in school experience teachings rooted in the cycle of the seasons.

The na-no-hana flower

Just as strict adherence to the saijiki in haiku composition does not offer much room for deviation, so too does the seasonal culinary calendar tend to keep ingredients in their time and place. Nevertheless, there seems a certain innate joy and comfort to see the return of specific ingredients again and again at a prescribed time every year.

While food education is itself a complex and nuanced topic, the cherishing of seasons and nature as viewed through food is an undeniable hallmark and one that helps to re-forge connections to nature and the world around us.

If you would like to learn more about food education and school lunch in Japan, visit Alexis’ web page to learn more about her documentary film Nourishing Japan. 


References:

Shirane, Haruo, Japan and the Culture of the Four Seasons (New York: Columbia University, 2013), xii.

Pulverized Food to Pulverize the Enemy!

By Nathan Hopson

This is the third in a planned series of posts on nutrition science and government-sanctioned recipes in imperial Japan.

Nukapan. Let me introduce our teatime specialty, rice bran fried in a pan. Mix wheat flour and rice bran, add a little water, and fry in a pan. Add no eggs or sugar. Fry for two minutes. It looks just like good custard. But it tastes bitter, smells like horse dung, and makes you cry when you eat it.[1]

Nukapan is an exemplary Japanese wartime culinary abomination, so much so that it features in Arthur Golden’s Memoirs of a Geisha, where the taste is upgraded from horse dung to “old, dried leather.”[2] However, it is not nukapan’s dubious gustatory merits that make it representative of the joys of cooking during the Pacific War. Instead, it is the use of flour and attention to waste reduction that make this a consummate early 1940s delight. Nukapan was both a direct response to food and nutrition shortages caused by catastrophic war planning failures and a manifestation of principles derived from a longer history of national nutritional activism in modern Japan.

Even before Japan plunged into the Pacific War, warning signs indicated the fragility of the Japanese food supply. True, despite constant Malthusian anxieties, Japan proper had achieved high levels of food self-sufficiency in the 1930s, but only by relying on its colonies, suzerains, and neighbors to make up the deficit. Japan’s wartime plan, such as it was, followed the Roman dictum, bellum se ipsum alet. Japan’s war planners believed they could fully integrate the resources―food, oil, etc.—of Southeast Asia into the metropole’s economy. “That strategy,” wrote Daniel Yergin, depended “on the integrity of Japan’s own shipping system.”[3] It failed. American forces decimated supply convoys, incapacitating Japanese shipping. Rice imports fell to ten-percent of prewar levels even before B-29 superfortresses destroyed over 130,000 tons of staples stored in Japan proper. No wonder, then, that the American Hunger Blockade was, according to postwar testimonies by Japanese leaders, “the Allies’ most effective tactic in ending the war.”[4]

Despite “adversity that stood a half-century of better living on its head,” the principles espoused for an ideal wartime diet remained relatively consistent.[5] By spring 1942, the daily menus that had been a fixture of Japan’s newspapers for two decades began the transformation from a combination of sensible middle-class fare with occasional aspirational “bougie foods” à la Japonaise to a grim set of “recipes for disaster” with dour headlines such as, “Meeting minimal nutrition needs with ingredients on hand.”[6] Though the punditocracy expressed confidence to the bitter end that “creative solutions for full use and consumption of foods to eliminate waste and maximize nutrition will appear,” they did not.[7] Instead, Japan doubled down on rationalization (viz., waste reduction and labor and resource optimization) and the substitution of nutritionally equivalent foods. The latter had been promoted by the Imperial Government Institute for Nutrition during the interwar years. Substitution’s primary wartime aim was to reduce rice consumption by supplementing or replacing it with other grains, potatoes, etc. Substitution was not limited to staples, however. No, substitution was comprehensive alchemy. Bread and noodles substituted for rice; beans, fish, insects, and wild birds for meat. Used tea leaves morphed into vegetables while potatoes evolved from vegetables to staples. Daikon and squash leaves―uneaten in better times―doubled as leafy vegetables and waste reduction. Porridges, soups, and other catch-alls dominated the menu, soaking up otherwise discarded ingredients and allowing creative caloric and nutritional supplementation. Potatoes were the most ubiquitous and despised of late wartime substitutes, but the keystone of substitution was “flour.”

Figure 1. Wartime postcard promoting rice conservation (setsumai). Author’s collection.

Perhaps the representative “flour-based food” (funshoku) was kōa pan (“Rising Asia Bread”). In fact, from acorns to kelp to rice hay, anything and everything that could be was powdered or pulverized and eaten, and animal feed and fertilizers such as soymeal and fishmeal found their way onto the menu, too. Comparatively, then, kōa pan might have been relatively harmless. A 1940 women’s magazine recipe called for flour, soymeal, baking powder, salt, powdered seaweed, fishmeal, substitute vegetables, and even sugar―which soon became unavailable. The accompanying illustration included butter; surely nobody was fooled.[8]

Figure 2. Kōa pan illustration (1940), reproduced in Saitō Minako’s Senka no reshipi (Iwanami Shoten, 2015:41).

These flour-based foods were controversial. Some praised their portability and long shelf life, others the ease of mass production and nutritional supplementation by eclectic mixing. Dissenters pointed out that many were, well, gross, and matched poorly with soy sauce, miso, and other traditional seasonings and condiments.[9] Digestive complaints abounded. Nevertheless, “flours” of all sorts gradually came to dominate wartime discourse―if not dinner―pushing out traditional “granular foods” (ryūshoku) such as rice.


In my next post, I will examine the surprising continuities of “flour-based food” in the early postwar years, and how American agricultural surplus helped complete a dietary transformation already underway during wartime.

This post is based on my “Women, Waste, and War: Food, Gender, and Rationalization in Wartime Japanese Discourse.” In Gender and Food in Contemporary East Asia, edited by Jooyeon Rhee, Chikako Nagayama, and Eric Li. Lexington Books, forthcoming.


References:

[1] Quoted in Thomas Havens, Valley of Darkness (Norton, 1978), 114.

[2] Arthur Golden, Memoirs of a Geisha (Vintage, 2011), 346.

[3] Daniel Yergin, The Prize (Free Press, 2014), 333.

[4] Sheldon Garon, “The Home Front and Food Insecurity in Wartime Japan: A Transnational Perspective,” in The Consumer on the Home Front: Second World War Civilian Consumption in Comparative Perspective, ed. Hartmut Berghoff, Jan Logemann, and Felix Romer (Oxford University Press, 2017), 51.

[5] Havens, Valley of Darkness, 123.

[6] “Asu no kondate,” Yomiuri Shimbun, March 3, 1942.

[7] Tsutsui Masayuki, “Kanso seikatsu no shihyō (12),” Yomiuri Shimbun, May 6, 1944.

[8] Saitō Minako, Senka no reshipi (Iwanami Shoten, 2015), 56.

[9] “Funshoku no senji futekikakusei,” Yomiuri Shimbun, September 4, 1944.

Very Frugal Ways to Cook Rice—Famine Prevention and Common Knowledge in Edo Japan

By Joshua Schlachet

If you’ve browsed The Recipes Project in the past several weeks, you may have raised an eyebrow at the unfamiliar black and white squiggles that decorate the top of our page (written, by the way, in a cursive form of premodern Japanese). As my October editorial duties slowly draw to a close, I couldn’t let the month go by without spoiling the mystery of this little recipe collection…of sorts…as economical in its prose as in its outlook.

Consisting of a single broadsheet (what you see above is the whole thing), Very Frugal Ways to Cook Rice (Daikenyaku meshi no takiyō), was likely produced around the time of Japan’s Great Tenpō Famine in the 1830s as a no-nonsense guide to help households squeeze a little more out of their staple grains. Rice prices could fluctuate wildly from season to season in time of scarcity, and to the extent that ordinary people could afford to eat (usually brown) rice at all, cutting it with cheaper vegetables and coarse grains became a strategy for survival.

Very Frugal Ways of Cooking Rice. Photo courtesy of the Waseda University Library Digital Collection of Historical Japanese Books.

Very Frugal Ways to Cook Rice was one of many vernacular publications—meant to help regular folks combat famine conditions—that circulated through the vibrant marketplace for commercial print during Japan’s Edo period (1600-1868). If it wasn’t given away for free, it was available for cheap, meaning a family could likely recoup what little they spent on the pamphlet itself in as little as a single meal. This was no small claim for those in need, and economizing became both a key premise in enduring food shortages and a central feature of every recipe listed here. 

What are the Very Frugal Ways to Cook Rice? The guide “instructs” readers on how to prepare rice seasoned and combined with a variety of inexpensive beans, roots, grains, and leaves, similar to the contemporary Japanese dish takikomi gohan. Each recipe indicates the proper proportions (five parts rice to four parts barley, for example) and basic directions for foods like barley, sweet potato, tofu lees, fava beans, millet, daikon radish, carrots, cow peas, red beans, as well as two kinds of “very economical” porridge that could stretch rice even further. Based on which ingredient one mixed in, a household could save a hefty thirty to eighty mon (a common denomination of copper coinage) on ten portions, a significant sum worth as much as $10 to $25 in today’s currency.

Contemporary image of Japanese mixed, seasoned rice (takikomi gohan). Photo courtesy of Ajinomoto Park.

Yet one thing continues to bug me about these very frugal recipes: why go through the trouble to teach people what they already knew? The directions themselves are so simple and intuitive as to border on obvious: cook beans, mix with rice; cut potatoes into chunks, mix with rice; boil leaves, season, mix. What’s more, families likely prepared such dishes in their homes already, making Very Frugal Ways redundant knowledge that didn’t bear repeating. Barring anything earth shattering within the recipes themselves, communicating frugality was itself the point. In a society where rice was not only the staple food but the basic unit of taxation and exchange, where running out signaled destitution, economizing as a lesson was worth reproducing the same old recipes, even if everyone already knew what was on the menu.