Ancient Japan from a Demographic Perspective

The purpose of this paper is to clarify the population dynamics of ancient Japan using spatio-temporal information science. Spatio-temporal information science is a computer simulation of time and space. In the first half of the eighth century, the population under the rule of the Japanese Ritsuryō State was about 4.5 million, and the country was in a state of chronic famine. In the first half of the ninth century, the population distribution showed a mosaic-like pattern with high population density in the central and western archipelago. With the exception of infectious diseases such as smallpox, famine caused by drought and rainstorms, and the resulting epidemics, were confined to regional areas, and the population of the areas seriously affected by famine and epidemics declined significantly. In the eighth century, the average annual population growth rate was between 0.1% and 0.2%, and the total population in the first half of the ninth century is estimated to have been between 5 million and 5.5 million