April 30, 2003



Keywords: Newsletter 

JFS Newsletter No.8 (April 2003)

In last month's issue of JFS, we introduced some elements of what made a sustainable society in Edo Period possible for 250 years, based on the research of Eisuke Ishikawa, one of Japan's leading researchers on the Edo Period, and his book "The Edo Period had a Recycling Society," ("O-edo recycle jijo," published in 1994, Kodansha Publishing Company).

The previous issue focused on the reuse and recycling practices of the Edo Period and this month we focus on its energy systems, showing that at the time Japan was a nation that functioned based on plants. Last month's issue:

As introduced in the previous issue, the population of Japan during the Edo Period was approximately 30 million people, a level that remained relatively constant throughout two and a half centuries. The population of Edo, at the time the largest city in the world, has been estimated at 1 million to 1.25 million people.

For approximately 250 years during the Edo Period, Japan was self-sufficient in all resources, since nothing could be imported from overseas due to the national policy of isolation.

The society of Japan during the Edo Period was driven only with solar energy. Plants transform solar energy, using water and hydrogen, into branches, wood, stems and fruit. If you harvest and use as energy the branches, plants and fruit that have grown in the past year, you are using the past year's solar energy in plant form.

During the Edo Period, about 80 percent of daily commodities was made from the solar energy of the previous year and 95 percent was derived from solar energy received in the past three years. This means that the Edo society was a sustainable society in which almost everything needed for living was provided by solar energy of the past two or three years.

The key to using solar energy in making goods and materials and recycling them to the very end was the full utilization of plants. Almost all goods and materials for food, clothing and shelter were made from plants. In this sense, almost everything was made from solar energy, with the exception of stone, metal, ceramics and other mineral-based materials.

Author Ishikawa wrote that Japan in the Edo Period was not only an "agricultural country" but also a "plant-based country" that co-existed with and depended on plants for the production and recycling of everything.

Take for example the lighting in the Edo Period. Commercial power generation and transmission started in November 1887 in Japan, when the first fossil fuel-driven power generator was put into operation. Until this moment, all lighting in Japan came from paper-made lanterns and wax candles using oil and wax produced here.

Oil for lighting was mainly from sesame seeds, camellia, rapeseeds and cottonseeds. People in regions where fishermen hunted whales used whale oil, and people in areas where fishermen caught sardines used sardine oil. Oil cake that remained after extracting the oil was also used as a quality nitrogen fertilizer.

Wax was made by squeezing the resin from the nuts of sumac and other trees. Since the production of wax candles was time-consuming and wax candles were very expensive, specialized buyers collected the drippings from candles, as introduced in last month's issue of the JFS newsletter.

In these ways, people used their own human power to extract solar energy from the previous few years stored in plants, and used the energy for lighting.

Rice has long been a staple food for the Japanese, and straw is one rice-making byproduct, the residue left after threshing rice to obtain grain. For every 150 kilograms of rice, about 124 kilograms of straw are produced. Straw was a precious resource for a wide range of uses relating to food, clothing and shelter in the past.

Farmers used about 20 percent of straw produced for making daily commodities, 50 percent for fertilizer and the remaining 30 percent for fuel and other purposes. Ash left after burning straw was used as a potassium fertilizer. In short, 100 percent of straw was used and recycled back to the earth.

For clothing purposes, straw was used to make braided hats, straw raincoats and straw sandals, among other items. Farmers produced such items during the agricultural off-season for their own use and as products to be sold for cash.

Relating to food, straw was used to make straw bags for rice, pot holders, and covering materials to produce "natto" (fermented soybeans). Farmers also used straw to feed cattle and horses and cover feedlots. Animal waste mixed with straw residue made compost for farming.

In the area of shelter, straw was a common building material for outside and inside the house, including the roof, "tatami" mats and clay walls. As you can see, straw, a byproduct of rice, was used widely in daily life and once it was used or burned, it returned to the earth.

In addition to straw, silk, cotton, hemp and other field-made materials were used for clothes. Paper was made of the bark of "kozo" trees. Since only branches were cut to obtain bark, there was no worry of excessive cutting of trees. And there were many kinds of recyclers for used paper in those days.

For warmth, charcoal made from wood was used in "hibachi" braziers and "kotatsu" (a fireplace with coverlet). Firewood was used to heat baths. Because such wood fuels came from brush, rather than from long-standing forests, all this energy used for daily life was derived from the solar energy of the past one to two years, in the form of branches and wood.

Author Ishikawa made an interesting calculation. At present, per capita tree stock in Japan is about 50 tonnes. The average growth rate of trees is about 5 percent per year, producing a dividend of 2500 kilograms of trees per capita every year, which, if burned, would produce about 10 million kilocalories of energy.

Today, the average Japanese person uses 40 million kilocalories per year. This means that a quarter of our energy requirement could be met with firewood today if all of the annual increment was burned. Since Japan in the Edo Period had about a quarter of the current population, all of its energy needs could have been met with firewood, even at current per capita consumption levels.

Almost everything was driven by human power in the Edo Period so energy consumption then would have been a fraction of the current level. Also, the country's forest area was larger then than it is today, meaning that people in the Edo Period needed less than the natural annual increment of growing trees to satisfy their energy needs.

Source: Eisuke Ishikawa, "The Edo Period had a Recycling Society," ("O-edo recycle jijo": published in 1994, Kodansha Publishing Company).