Page 229 - Changing Living Spaces

Agricultural Crises Due to Flood, Drought, and Lack of Sunshine

to control the flows of rivers. This was only the beginning of the histo-
ry of the ‘conquest’ of nature in Japan. It seems to have been a victory
of modern river improvement. Flooding in Japan has become surely less
frequent. However, especially sediment-related disasters are caused, re-
cently because of climate crisis, almost every year by extreme rainfall
in Japan.
Traditional technical means of controlling rivers were pursued not only
through labour-intensive efforts of the inhabitants, but also through var-
ious and systematic works on the banks based on communication and co-
operation between villages. However, under the Tokugawa shogunate, no
regional or national control system was possible, especially for long rivers
flowing from the highest mountains to the seashore, because such rivers
were divided into many regional and local dominions, and a unified riv-
er improvement control system based on national capital did not yet ex-
ist (Okuma 2007, 20).
In contrast, pre-modern waterproofing technologies did exist and
should be considered the result of cumulative learning from ancient
times. The seventeenth-century Hyakusho Denki6 (Chronology of Farming)
shows a series of 27 instructions on river improvement and water regula-
tion, detailing dam construction, river drainage, and flow control meth-
ods. The collections of knowledge and technology were available to all
Japanese villages. Two of the most important recommendations from the
Hyakusho Denki were that (1) the residents themselves should check the
water levels in their rivers and the weather conditions on a daily basis,
and (2) that they should repair water facilities and dam reinforcement in-
struments every year and review river control construction projects as
necessary (Furushima 1997, I, 187–8). In particular, the control of small
rivers seemed to be well served by these instructions.
Today, the Japanese Ministry of Land, Infrastructure, Transport
and Tourism defines the types of rivers in Japan (Ministry of Land,
Infrastructure, Transport and Tourism Japan, n.d.-a). First-grade riv-
ers are regulated by the River Law and administered by this Ministry. In
2010, there were 109 first-grade river basins and 13,935 rivers belonging
to such a basin. The shortest stretch of the main first-grade river is 28 km
long and the longest stretch, the Shinano River, is 367 km long. The larger

6 Furushima (1997, I, 186–232). The part of the book that was written from 1680
to 1682 shows technological attainment of perfection. Explanations of the book
by Furushima (1997, II, 203–07).

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