W.W. Farris
time. Life expectancy was low, with a majority of the population not reaching age five. If a
person lived beyond five years, then he or she could expect to live to about forty. These figures
seem to reinforce Thomas Hobbes’ characterization of life “in a state of nature” as “nasty, brutish
and short.” Moreover, the reader should realize that these figures are derived from Mino prov-
ince, during a time in which no famines or epidemics were recorded. During harsh times, fertility
undoubtedly plunged, mortality spiked, and life expectancy probably dropped below twenty.
For those living during the eighth century—even aristocrats—life was hard indeed.
Japan’s population during the Heian and Kamakura periods: 800–1300
In contrast to the amazingly well- documented eighth century, the next five centuries force
demographers to assemble bits and pieces of evidence to evince population trends. A few figures
seem to be more reliable than others. For example, the nineteenth- century scholar Yokoyama
Yoshikiyo (1826–1879) utilized a passage from The History of the Sung Dynasty (Sung shu) to derive
a credible number for the era 947–1003.^25 The Chinese history quoted the Tōdaiji monk Chōnen
as purportedly listing the number of taxable adults in Japan as 883,329 men. Yokoyama then
assumed that there were five taxable males per household and that there were twenty- five persons
in every household, based on the tenth- century Twelve- Article Opinion Memorial authored by
Miyoshi Kiyoyuki (847–918). The total population was about 4.4 million.
As noted above, Kitō had inferred his own population totals for the Heian period (794–1185).
For the mid- tenth century, Kitō used Minamoto Shitagō’s encyclopedia (Wamyō shō). That work
recorded the total number of rice paddies in Japan between 931 and 938 at roughly 862,000 chō
(one chō equaled three acres). Believing that 0.16 chō was necessary to support one person over age
six, Kitō divided and arrived at a population of 5,375,000. He then added 250,000 for urbanites
and another figure for those aged six and under to infer a total population of 6,437,600 for all
Japan around 950. In 2000, he adjusted this figure to a total of 6,441,400. Kitō derived a popu-
lation total for 1150 in a similar manner. Utilizing what he thought was the total paddy land
figure (926,000 chō) from a later encyclopedia named Shūgai shō, Kitō obtained a figure of
6,713,500. In 2000, he slightly revised that number to 6,836,900.
Kitō’s calculations were groundbreaking, but scholars have expressed several doubts. First
there is the question of how much rice paddy was indeed necessary to support a person? Kitō had
applied a legal standard from the eighth century to arrive at his divisor, but one could be par-
doned for wondering whether that standard worked equally as well during the mid- tenth and
mid- twelfth centuries. Then, too, he had assumed that the only livelihood worth noting was rice
farming, when it was clear that a substantial portion of the population was engaged in other
occupations, such as dry cropping, fishing, logging, swidden agriculture, and many others.
Finally, techniques of field measurement were often inadequate during the Tokugawa period and
before, especially since lands included barren or uncultivated arable. It seemed that Kitō’s infer-
ences needed to be taken with a grain of salt.
In 2009, I tried to utilize the same sources but refine Kitō’s method. First, I noted that Sawada
and his rival Takigawa Masajirō had calculated the amount of rice paddy necessary to support
one person at much higher levels than the legal norm. In other words, they believed that the
divisor needed to be higher than 0.16 chō.^26 I averaged the estimates of Sawada and Takigawa and
arrived at a divisor of 0.217. To allow for abandoned fields, I subtracted 25 percent from the
totals in the two encyclopedias, a conservative estimate based on land records of the age. Divid-
ing that lower total by 0.217 yielded 3,459,179 persons dependent upon rice farming.
Estimating the total number of folks living by occupations other than rice farming is difficult.
Around 1600, Hayami Akira thought that only about 10 percent of the populace did so; other