Before the days of oil, coal and other fossil fuels, firewood from the forest and smaller woodlands was the primary fuel. In Japan, a land rich in forests, the people burned both firewood and charcoal. The people made charcoal by charring pieces of wood not suitable for construction, preferring wood from trees like kunugi or nara (two types of oak). Charcoal burns for a long time, emits no smoke, and is easy to transport because it is lightweight; it was the fuel of choice throughout the country for heating and cooking.

Osato Yukihiro still makes charcoal in a kiln constructed the old-fashioned way, with only earth and stone. From the forest near his home in Wakayama Prefecture he gets kunugi and nara wood, as well as bamboo, for his kiln. He heats the kiln to about 800°C and keeps the fire going for three or four days, until the wood and bamboo are properly charred. The kiln has to be watched all the time, and the firebox has to be fed with firewood.

"Changes in the smoke tell me what adjustments to make. Reading the smoke is the most difficult part of the process. The hot smoke has to circulate properly for the wood to carbonize, and if I'm not careful the flames from the firebox will light the wood in the kiln."

After World War II, most homes in Japan switched from charcoal to fossil fuels like kerosene and gas, and charcoal production plummeted. Today, though, a growing number of restaurants are advertising charbroiled cuisine, and demand for charcoal is increasing among campers as well. Charcoal offers some surprising benefits, adding to its popularity. For example, it absorbs unpleasant odors, and the wood vinegar produced during the charcoal making process can alleviate hay fever and improve the skin.