Komoro-shi

In the most recent Population Census the population is about 41,000 (40,991 in 2020). From 46,158 in 2000, through 45,499 in 2005, 43,997 in 2010 and 42,512 in 2015, it reached 40,991 in 2020 — some five thousand fewer over twenty years.

Look into the makeup and the figure of a hillside town that served as both highway post and castle town appears. The share aged 65 and over rose from 20.8% in 2000 to 33.6% in 2020 — up about thirteen points over twenty years, past three in ten. Households with children were 20.0% in 2020. The childcare waitlist was zero in both 2024 and 2025. The Fiscal Capacity Index was 0.58 in FY2023 — a middling level for an inland city, where its own tax revenue covers a little over half of expenditure. The numbers show a hillside castle town with the two faces of highway post and castle easing its population down toward forty thousand while raising the town’s age. Why it takes this shape cannot be read without going back to the history of the post and the castle.

This town’s skeleton is set by its position as the first post of the Hokkoku Kaido, by a castle built by a Sengoku-era warlord, and by a hillside castle town that overlaid the two. The first layer is the highway. This town opened as the first post of the Hokkoku Kaido, which branched north from the Oiwake post on the Nakasendo. The shogunate valued this highway, which carried gold from the Sado gold mines to Edo, as second only to the Five Highways, and inns and merchant houses lined the post. The highway post was this town’s old foundation.

But this town was not only a post. A Sengoku-era warlord built a castle on this land and laid out a castle town. On this land, where the highway had run from early on, the two functions of castle and post overlaid in one town — a point that gave it a thickness unlike a mere post station. The castle town was opened on the sloping land at the southern foot of Mt. Asama, becoming a distinctive layout with many slopes. Later, in the town of those castle ruins, a poet, over a few years as a teacher at a school, changed from poet to novelist. The first post of the Hokkoku Kaido, the Sengoku castle, and the hillside castle town — this town’s shape stands on a history that overlaid two faces, the highway post and the castle, on a slope at the southern foot of Mt. Asama.

What characterizes Komoro is that, while carrying the two faces of highway post and castle, it eases its population down gently — some five thousand over twenty years, toward forty thousand. From 46,158 in 2000 to 40,991 in 2020, the decline held to a little over ten percent. It can be read that, even after railways and expressways came, the thickness of the urban area since highway-post and castle-town days kept the core of the town’s living. But some of the younger generation moved toward larger cities, and the town’s age has risen overall. That the share aged 65 and over reached 33.6% in 2020, past three in ten, is one sign of this.

On the other hand, the childcare waitlist was zero in both 2024 and 2025, and households with children were 20.0% in 2020. A Fiscal Capacity Index of 0.58 is a middling level where its own tax revenue covers a little over half of expenditure — leaning on the local allocation tax, yet not extremely thin. The hillside castle town with the two faces of post and castle now eases its population down toward forty thousand while raising the town’s age. The decline is a little over ten percent, aging is past three in ten, and fiscal stamina is middling. Had it been a post station with only one face, its core would have thinned easily when the highway’s role shifted to the railway; but the double stance of being both post and castle town held that thinning to a shallow one — so Komoro’s numbers can be read.

Komoro’s history is not one thing. It has the position of being the first post of the Hokkoku Kaido, which branched from the Oiwake post on the Nakasendo, valued by the shogunate as a highway that carried gold from Sado to Edo. It has the character of also serving as the castle town of a castle built by a Sengoku-era warlord, overlaying the two functions of post and castle in one town. And it carries a literary history in which, in the town of those castle ruins, a poet changed into a novelist. The sloping land at the southern foot of Mt. Asama gave rise to a distinctive castle-town layout with many slopes.

Komoro is a town where the highway post and the castle laid two faces on a slope at the southern foot of Mt. Asama. From the first post of the Hokkoku Kaido, to a Sengoku castle, to a hillside castle town, to a poet’s transformation — the sloping land at the southern foot of Mt. Asama held both the highway post and the castle town on its tilted incline. At the starting point of the road that carried Sado’s gold, a Sengoku castle settled in, and later a poet became a novelist at those castle ruins. Had it been a town of only the post, its core would have thinned the day the highway’s role shifted to the railway. That the castle remained as another face keeps the urban area atop the slope to this day.