The historical demography of Japan to 1700estimates range much higher. For instance, during the eighth century dry cropping supported about
20–25 percent of rural folk. In the end, I multiplied my total of about 3.5 million by 1.4 to arrive
at 4,842,851 rural commoners. Adding another 100,000 for city dwellers and about 600,000 for
slaves and undetected persons, it seemed that Japan’s population around 950 was about 5.6 million.
Applying the same method for the figure from 1150 led to a total of 5.9–6.3 million.^27
Even these attempts to use the rice paddy figures from the Wamyō shō and the Shūgai shō did
not satisfy some. In a review of my work, Charlotte von Verschuer argued that my generous
allowance for the population not consuming rice was insufficient and that the two sources could
not be used in infer population.^28 There is, however, a rejoinder to Verschuer’s argument.^29 The
totals contained in the two encyclopedias may not have been actual land under cultivation, but
rather a calculation of all economic activity computed in terms of rice. In this way, the issue
raised by Verschuer becomes moot. When the populations for 950 and 1150 were tabulated over
again with the figures from Wamyō shō (862,806 chō) and Shūgai shō (956,558 chō) representing all
economic activity, the total populations come to 5.0–5.6 million in 950 and 5.5–6.1 million in
- In other words, Japan’s population seems to have remained static between the late 700s and
1150, just as Yokoyama and Kitō had argued.
Reasons for a static population over the era 800–1150 are not difficult to find. Primarily,
bouts with killer epidemics of smallpox, measles, mumps, dysentery, influenza, and other dis-
eases seem to have taken a drastic toll on the population. I have cited two epidemics, one an
unknown disease dating to 865–866 and the other a smallpox outbreak occurring during 993–995
as carrying off about 34 and 25 percent of afflicted populations, respectively. And smallpox—
“the most terrible minister of death”—is recorded as visiting the archipelago every thirty years
from the early eighth century until 1051. Influenza became a terrible scourge as the climate
turned colder and wetter during the late eleventh and twelfth centuries. Finally, archaeological
and cultural evidence records the widespread fear unleashed by disease during the centuries from
650 through 1150. Famine and ecological degradation added to the increased death rate.^30 In
effect, stasis seems to be the most reasonable answer to the problem of what happened to Japan’s
population between 800 and 1150.
The transitional Kamakura epoch represents another time for which sparse sources make it
difficult to infer demographic trends. I computed the only number that is even close to reliable in
Japan’s Medieval Population: Famine, Fertility, and Warfare in a Transformative Age.^31 Pointing to the
extant Great Rice Field Registers (ōtabumi) dated to the early and middle Kamakura age
(1185–1333), I noted that each contained data purporting to specify the total rice paddy acreage
in scattered provinces. I combined these Land Registers into four groups: six from Kyushu, five
from west- central Japan, and one each from the northern Japan Sea littoral and the Kanto plain.
Decreasing the divisor to account for a modest improvement in agricultural productivity between
1150 and the 1200s, I then applied a method analogous to the methods used to compute popu-
lation from the Heian period Wamyō shō and Shūgai shō. The results of these calculations suggested
moderate demographic growth in Kyushu, stasis in west- central Japan, and decreasing popula-
tion in eastern and northern Japan. From this method, I estimated the population of the Japanese
archipelago around 1280 at 5.7–6.2 million. In other words, stasis was still the watchword in
Japan as late as the end of the thirteenth century.
Objections can be lodged against this figure and the notion of continuing stasis for Kamakura
Japan. Vershuer’s criticism that a substantial population survived by occupations other than rice
farming has particular weight, although the figures from the Great Land Registers, like those
from the Heian period, can be considered records of all economic activity computed in rice, a
commodity that has always had meaning as currency. Then, too, Toda Yoshimi proposed in
1967 that the late Heian and Kamakura epochs constituted an “era of widespread land clearance”