C. von Verschuer
have been able to find evidence of this practice throughout Japanese history by analyzing the early
eighth- century place names of small village units (sato) in the eighth- century documents of the
Shōsōin, the names of Shinto shrines in the Engishiki (927), dictionaries and poetry of the tenth and
twelfth centuries, medieval estate documents, agricultural treatises of the eighteenth century, and
local reports of the nineteenth century. William Wayne Farris has also discovered references to the
slash- and-burn tradition in the Japanese mythology as well as in early poetry.^25
All these data attest to the existence of swidden cultivation in Japan throughout the centuries
but they do not provide figures on the scale and volume of the swidden crops, nor on their share
in food production of premodern Japan. Far from being a marginal practice, however, slash- and-
burn farming represents the very first and most basic form of agriculture. In his review of agri-
cultural history, Andō Hiromichi, states that the idea of swidden farming (yakihata) as the earliest
form of agriculture was adopted by scholars in the 1970s, and that since the 1990s this concept
gave an impetus to a wider perception of the Japanese traditions altogether. Andō defends the
concept of a “Composite Japanese culture” with multiple farming practices combining “non- rice
farming” (hi- inasaku nōkō) and a “swidden cropping culture” (yakihata bunka), as well as a “irri-
gated rice growing culture” (inasaku bunka).^26 We now understand that various forms of food
production have been practiced throughout history along with irrigated rice. These forms even-
tually marked the Japanese diet.
Food production and diet
Each type of food acquisition presents its own specific features: Irrigated rice has high yields and
produces many calories on a small acreage. Rice can grow without manure, because water con-
tributes potassium, calcium, and magnesium to the soil. Yet rice needs intensive care for leveling
or terracing, as well as the maintenance of hydraulic systems. And rice was heavily taxed. In the
premodern periods, farmers or proprietors retained less than half their rice harvests, after taxes
and other deductions. And with its need for multiple rounds of weeding, irrigated rice is the most
labor- intensive form of agriculture.
Permanent dry grain fields have low yields—about one- fifth those of rice yields. They need
much added fertilization. Green manure, or composting, remained the principal method before
the introduction of commercial fertilizers consisting of vegetable oil or dried fish meal in the
seventeenth century. Green manure requires wasteland nearby, and demands about two months’
work each year cutting grass to fertilize one hectare of land. Without fertilization, harvests
decrease by half or more from the second year. Permanent fields therefore needed intensive care.
But in contrast to irrigated rice, most dry crops were not taxed by the government until the
seventeenth century, and thus the harvests fully belonged to the farmer or the proprietor.
Swidden farming needs no soil fertilization, thanks to the ashes that remain on the field after
burning. The soil minerals are also replenished by including a bean crop within the four- year
crop rotation. The yields of swidden fields are the same as those of permanent dry fields, but they
are sometimes easier to manage. Today the high demography in some countries leads to the
failure to allow sufficiently long recycling periods for the forests and results in significant forest
destruction. But this was not the case of medieval Japan, where shifting cultivation was a sustain-
able resource in food production. It was not subdued to taxes and, combined with plant gather-
ing, could feed the farmers’ families.
Gathering or harvesting of wild edible plants was widely practiced through the entire realm
and in all times. Green plants and fruits provide vitamins, tubers starch, beans proteins, and nuts
and seeds provide oil and high calories. Thanks to their high biodiversity the mountain areas of
Japan offered plentiful plant foods.