Kochi Prefecture

Kochi’s height leans on a single thing—the physician count (per 100,000 population)—and it is fragile for that very reason. It overshoots by about 2.0σ even compared with the level expected from its overall capacity, standing out as a “hidden strength” beyond its underlying power—but remove it and the support is thin. At the lower end sits the lowest “population change rate.” Take away these two poles and the indicators fall almost into the vicinity of the national average, with standard dispersion as a profile.

What is structurally important, however, is that the composition of its overall advantage in effect leans on a single pillar, the “physician count” (73% of the strength). Imagine Kochi with the pillar removed from your mind, and the overall advantage all but disappears. What must not be confused here is that this is a story of “the composition of the overall advantage leaning on a single pillar”—it does not mean that medicine itself is fragile. Seen on a separate axis, medicine is firm at its base, including not only the physician count but also average life expectancy, and that point is a structural strength, not a transient one. What stands on a single leg is the way the overall score is assembled; I want to read that apart, as a layer separate from the thickness of the medical category. The weaknesses are concentrated in the economic-strength category—the population change rate, per-capita prefectural income, the complete unemployment rate—and the clean division of strength and weakness by category is this prefecture’s feature.

Tourism resources such as Katsurahama and the Shimanto River, too, do not directly fill in the real numbers of population and income. When the strength is a single thin pillar, the question to ask is what remains if that pillar breaks. The story that produced Ryoma and the thickness of the landscape that is the last clear stream do not rescue the thinness of a number like the physician count’s 73% share—I want to read the thickness of the story and the thinness of the numbers while keeping them lined up on separate maps.

In speaking of Kochi’s future, the great Nankai Trough earthquake must be placed as the heaviest premise. By the prefecture’s published figures, a 1m tsunami reaches the coastline in about three minutes after the earthquake at the earliest, and a maximum tsunami height of over 10m is projected for nearly the entire coast except the inner reaches of Urado Bay and a few other areas. Ground subsidence, moreover, is severe: Kochi City is projected to subside by about 1.5m, leaving about 2,800 ha of the central urban area under prolonged inundation, and Sukumo City to subside by about 2.4m, leaving about 559 ha under prolonged inundation—a projection not of transient flooding but of land sinking below sea level over the long term. The long-term evaluation by the government’s Earthquake Research Committee places it in the highest-rank occurrence-probability band. Even with the timing uncertain, the certainty is a government official value, and the scale of impact is extremely large.

Onto the “single thin pillar that is the physician count” seen in the previous section, this disaster and the weight of population dynamics overlap in double. The generational turnover concentrated in 2031–33 and the phase of a rising vacant-home ratio point downward, and caution against simply extrapolating the present standard profile is especially heavy here.

A present supported by a single thin pillar; an extreme disaster risk of a tsunami in three minutes and prolonged inundation; the certain weight of population dynamics. I will not round these into one—disaster especially changes meaning decisively between coast and inland; the projection that “2,800 ha of central Kochi City is under prolonged inundation” carries a meaning separate from inland figures. As someone who has made numbers a profession, I do not want to skip the work of writing disaster on a separate table point by point. The individual schedules, plans, and degrees of certainty can be followed one by one in the development roadmap at the bottom of the page.