Isehara-shi

In the most recent Population Census the population is about 102,000 (101,780 in 2020). This city’s population, with neither a step formed by a great merger nor a sharp rise or fall, moved nearly flat around one hundred thousand for twenty years — from 99,544 in 2000 to 100,579 in 2005, 101,039 in 2010, 101,514 in 2015, and 101,780 in 2020. It is a rare, gentle curve in which the town at the foot of Oyama, neither rising nor falling, held almost horizontal.

Looking at the makeup, the figure of a central Kanagawa city emerges. The share aged 65 and over was 26.1% in 2020, a quarter and more. Households with children make up 19.0%, and the childcare waitlist stood at 16 children in both 2024 and 2025 — very small, yet continuing. The Fiscal Capacity Index was 0.92 in FY2023, near one, meaning that the city can cover most of its expenditure on its own tax revenue, a high stamina for a regional city. The town of the Oyama pilgrimage shows in its numbers the figure of holding its population nearly steady while carrying a high fiscal stamina. Why it takes this shape cannot be read without going back to the origins of the mountain of worship.

Isehara’s skeleton is set by Oyama, the mountain of worship rising in the city’s northwest. With Oyama Afuri Shrine at its summit, this mountain has from of old been held a place of mountain worship, and in the medieval era it received the reverence of the warrior houses. As a deity governing rain, and as a mountain enshrining Oyamatsumi-no-okami — the father of Konohanasakuya-hime, enshrined on Mount Fuji — it has gathered people’s faith. The mountain itself sets this town’s origin.

That faith bloomed greatly in the Edo period. The “Oyama pilgrimage,” in which many common folk climbed Oyama for a mix of worship and recreation, spread widely; artisans such as steeplejacks carried giant wooden swords on their shoulders from Edo and, purifying themselves under a waterfall, made for the summit — a form of pilgrimage with few parallels. The scene was painted in kabuki and ukiyo-e, and it is said that, when the population of Edo was around one million, as many as two hundred thousand pilgrims visited Oyama in a year. The “double pilgrimage,” worshiping both Oyama and Mount Fuji, was also popular. The Oyama pilgrimage is now certified as Japan Heritage.

These pilgrim paths became the prototype of today’s Oyama-kaido road, and Isehara, at the foot, developed together with the function of a post-town receiving the pilgrims. Beginning from a mountain of mountain worship, becoming the foot of the Oyama pilgrimage in which the common folk of Edo formed lines, and turning the pilgrim path into a highway — this town’s shape stands on the origin set down by a mountain of worship.

What characterizes Isehara is that, while many regional cities lose population, it has held its population nearly flat for twenty years. Moving around one hundred thousand, neither rising nor falling, with the share aged 65 and over staying at a quarter and more. It reads as a sign of the character of residential land opening onto the Sagami plain, incorporated into the commuting range toward Tokyo and Yokohama, having supported the population. At the same time, it has not risen sharply either — its central-Kanagawa position, somewhat distant from the center, generated neither an explosive inflow nor a sharp outflow, it can be seen.

That stability surfaces in the fiscal figures too. A Fiscal Capacity Index of 0.92 is near one, a level able to cover most of expenditure on its own tax revenue, high for a regional city. It reads that residential land as a commuting range, and the commerce and industry gathered at the foot, give thickness to the tax source. The childcare waitlist stood at 16 children in both 2024 and 2025 — very small, yet continuing — leaving the provision against demand as a remaining task. The town of the Oyama pilgrimage now holds its population nearly steady, aging at a quarter and more, fiscal stamina on the higher side. Population flat, aging not too deep, fiscal stamina on the higher side — these three folded together make the present of the gentle town at the foot of Oyama. Take out the flat population curve alone, or the fiscal capacity alone, and you cannot grasp the feel of this town.

Isehara holds several functions of its own. One is the origin of being the foot of a mountain of worship crowned by Oyama Afuri Shrine, with an origin as a place of long-standing mountain worship. Another is its character as the gateway to the Oyama pilgrimage in which the common folk of Edo formed lines, retaining the memory of pilgrimage certified as Japan Heritage and the Oyama-kaido road that the pilgrim path opened. And its position as a commuting range toward Tokyo and Yokohama gives this town the face of residential land on the Sagami plain.

Isehara is a Sagami town that carries a mountain of worship. From the foot of Oyama, a mountain of mountain worship, to the gateway of the Oyama pilgrimage, and on to a commuting range on the Sagami plain — the geography of opening onto the Sagami plain with Oyama at its back drew in, in turn, the faith, the pilgrim path, and the residential land. From a mountain of mountain worship to the gateway of the Oyama pilgrimage, and on to commuting-range residential land — the functions move, yet the position of the foot of Oyama alone does not.