W.W. Farris
in Japan, such as occurred in Europe between 900 and 1150.^32 This view has fallen on hard times,
however, in recent research.^33 Finally, Saitō Osamu, a demographer of the Edo period, has
inferred a population for Japan in 1250 of 6.5 million, further buttressing my argument for
demographic stasis during the thirteenth century.^34
Intriguingly, disease clearly receded as a major mortality factor during the thirteenth century.
McNeill cites evidence that both smallpox and measles, two deadly afflictions of the past, attacked
mainly infants and young children by the mid-thirteenth century.^35 Sources mention only one
rather benign new disease (chickenpox) during the epoch 1150–1280. Transportation and other
factors affecting the transmission of microorganisms remained unchanged, and immunity levels
had probably risen. The only pathogen striking with greater lethality and frequency was influ-
enza, and therein lies an important hint for understanding the reason that population was static
despite the decreasing role of parasites. If, therefore, the population of the archipelago remained
about the same from the mid twelfth until the late thirteenth century, the reasons for stasis must
have been different from those of previous centuries, suggesting an important change in Japan’s
demographic and economic dynamics.
In a word, climate induced three devastating multi- year famines: Yōwa (1180–1182), Kangi
(1229–1232), and Shōga (1257–1260). In the first case, drought and heat crippled farming
throughout much of western Japan, as the Ise Taira attempted to hold on to power during the
Genpei War of 1180–1185. More importantly, unusually cold and damp climate induced the last
two famines. Apparently, volcanic eruptions occurring throughout much of the world led to this
climatic trend.^36 For example, during the Kangi famine of 1229–1232, it snowed in mid- summer.
Death rates were apparently high—at one farm in central Japan, 16–22 percent of the population
dropped dead in one month. At another, also in central Japan, the number of farming units shrank
by 42 percent before and after the famine. Numerous other factors also indicate that the Japanese
population starved for much of the thirteenth century.^37 War played an increased role in wreak-
ing havoc with the food supply, as marauding troops stole food and abused peasants during the
frequent conflicts of the late twelfth and thirteenth centuries.^38
To summarize: although the evidence is thin and admits of varying interpretations during the
period 800–1300, the most reasonable conclusion seems to be that demographic stasis was the
rule for these five centuries. In other words, these five hundred years constitute the end of Japan’s
second population cycle. Things were about to change, however.
The revival of growth, 1300–1700
Several factors suggest the beginning of transformative growth around 1300. The toll from path-
ogens, although a constant drain on the youthful population, seems to have dropped even further.
Although there is uncertainty about the climate, it seems likely that there was a steady warming
during the late fourteenth and fifteenth centuries, and as the climate became more benign, the
incidence of major famine fell to perhaps as low as once every ten years. A death register from
Yūgyōji in the Kanto region suggests that while people were chronically undernourished, the
most deadly period was 1346–1385, a time that coincided with hostilities known as the Wars
Between the Northern and Southern Dynasties (1333–1392). Warfare became more deadly, not
so much for combatants as for the general populace serving as victims of the marauding armies.
Finally, economic revival sustained by agronomic, engineering, and social improvements in agri-
culture, as well as a commercial and industrial boom focused on western Japan, indicates the
onset of continuing demographic growth.
I have estimated the population of the archipelago at 9.6 million using the relative size of
armies. The reasoning works as follows: For the eighth century, when a draft army consisting