C. von Verschuer
speedily to a rice- growing society at the dawn of the Yayoi period (from the early first millen-
nium bce to the late third century ce).^1
Rice cultivation entered the historical records from the seventh century. From the seat of the
royal court in the Kinai region of central Honshu, the Yamato rulers carried out land surveys and
population censuses throughout the realm, and forced irrigated rice growing on the entire popu-
lation. The Yamato court also adopted from Tang China the ritsuryō system of administrative
state institutions. In these administrative codes, rice was decreed to be the base for the fiscal
economy and the land system.
The Yamato court undertook large- scale public works in the central region from the seventh
century. And from the eighth century, the great monasteries and noble elites initiated countless
irrigation works on their private estates in the provinces. Rice paddies need to be leveled in order
to maintain an even water depth for nourishing the rice during the growing period. Thus land
clearing projects and the management of irrigation facilities continued through all periods of
history, and were carried out by land proprietors, court elites, and provincial powers. Taxes on
agricultural product and land all were assessed in terms of rice. Irrigated rice served as the basic
state income.^2 It eventually continued to provide the main accounting device in the public
economy until the end of the Edo period.
The period of the tenth to sixteenth centuries is generally considered to be a time of signi-
ficant agrarian expansion in Japan marked by repeated land clearance campaigns sponsored
by local governments and landlords. This general view however needs some verification.
According to ancient dictionaries from the tenth to fourteenth centuries, the provinces of the
entire realm amounted to 900,000 to 1.1 million hectares of rice fields. The figures in cen-
suses then jump to 1.6 million hectares in 1600 and to 2.9 million hectares in 1700. These
figures have formerly been interpreted as an expansion in rice production that has in turn
been explained by technical advances. Yet it has been overlooked that these data only par-
tially reflect reality.
From the 1980s Kuroda Hideo and Kimura Shigemitsu did innovative research on dry
grains. Until then, agriculture had been perceived as synonymous with irrigated rice cultiva-
tion and archaeological and historical research ignored millet. By scrutinizing the historical
records of the tenth to fifteenth centuries, however, Kimura has shown that millet was abun-
dantly grown in all provinces. He has drawn attention to the fact that medieval dictionaries
registered only taxable rice paddies, and failed to register dry fields. It was only after the agrar-
ian reforms of Toyotomi Hideyoshi (1536–1598) in 1598 that non- irrigated fields, i.e., perma-
nent dry fields, entered public accounting. The figures available to us, therefore, compare on
one hand an agricultural base of around 900,000 hectares of rice paddies alone for the earlier
period up to the fourteenth century, with, on the other hand, 1.6 million hectares of total
arable land (including both irrigated and dry fields) for around 1598. In contrast, the figures
after 1598 do reveal a net expansion of total arable land from 1.6 to 2.9 million hectares by
- The data of the ancient dictionaries, then, suggest a rather stable acreage of irrigated rice
paddies during the medieval period (because they compare the figures limited to rice acreage
up to the fourteenth century with figures of both rice and other grain acreages in 1589). As for
technical advances, outstanding innovations were limited in the medieval period and a high
net increase in overall rice production cannot actually be observed before the seventeenth
century.^3 In contrast, historians and archaeologists have, since the 1980s, become aware of the
high importance of millet and other dry cereals in agricultural history. The presence of these
grains is indeed attested to since Neolithic times.