Iwamizawa-shi

In the most recent Population Census the population is about 79,000 (79,306 in 2020). This city’s population has a step caused by an annexation merger. In 2006 Iwamizawa-shi annexed the village of Kitamura and the town of Kurisawa, becoming the present city area. Before annexation it was 85,029 for the former Iwamizawa-shi in 2000 and 83,202 in 2005; after adding the two municipalities it became 90,145 in 2010, and from there fell on a steep slope after annexation, to 84,499 in 2015 and 79,306 in 2020.

Look at the contents and the figure of a town that carried the era of coal, shrinking, appears. The share aged 65 and over rose from 19.5% in 2000 to 36.4% in 2020, nearing four in ten. The household-with-children rate is low at 16.0% in 2020, and the childcare waitlist was zero in both 2024 and 2025. The Fiscal Capacity Index was 0.38 in fiscal 2023; own tax revenue covers only about four-tenths of expenditure, with large reliance on the allocation tax. The figure of a town that was a railway node, losing population and deepening aging after annexation, its finance propped by the allocation tax, appears in the numbers. Why this shape arises cannot be read without tracing back the origins of coal and rail.

Iwamizawa’s skeleton is set by the Sorachi region that held coal and by the railway that carried that coal to the ports. The old layer is rail. In the mid-Meiji period, railways for carrying the coal dug across the Sorachi region to the ports of Otaru and Muroran ran through this ground one after another. As several lines crossed here, Iwamizawa grew as a node of the railways that carried coal. The town’s name is said to have come from “Abasawa,” a turn on the bathing place by the river where the laborers building the road between Sapporo and Horomui eased their fatigue in the hot water.

And this town held a vast facility for sorting freight cars. As the cars loaded with coal gathering from across Sorachi increased, the marshalling yard that sorted them by destination was expanded, and at its busiest is said to have handled as many as two thousand cars a day. This marshalling yard was said to be the largest east of Tokyo, and the former Japanese National Railways counted it among the nation’s “railway towns.” But amid the shift of energy from coal to oil, the mines of Sorachi were closed one after another, and in 1989 the mines within the city too ended their role. A railway node gathering coal and sending it out to the ports — this town’s form stands upon the origins of the coal of Sorachi as a resource and of the railway that carried it.

What characterizes Iwamizawa-shi is that, carrying the origin of a railway node that carried coal, it loses population and deepens aging after that coal’s role ended. From 90,145 in 2010, with the two municipalities added, to 79,306 in 2020, some ten thousand were lost in ten years. As the mines of Sorachi were closed one after another and the role of the railway that carried coal shrank, the industrial footing that held up the town reads as having thinned. In addition, a flow of the younger generations moving to cities such as Sapporo continues. That the share aged 65 and over nears four in ten at 36.4% in 2020 is an expression of that population composition.

Meanwhile, the childcare waitlist has held at zero. Against the reduced population, the childcare capacity reads as kept. The Fiscal Capacity Index of 0.38 is a level where own tax revenue covers only about four-tenths of expenditure, with large reliance on the allocation tax. As a town after the industrial footing held up by coal and rail thinned, it mirrors how its own tax base has its limits. The town that was a railway node loses population and deepens aging after coal’s role ended, while holding a zero waitlist, its finance propped by the allocation tax. A falling population, aging nearing four in ten, a weak tax base — these are a single profile that a Sorachi town, raised as the keystone of the flow that carried coal, shows after it lost that flow.

The functions Iwamizawa holds are born from the single point that coal always passed through this ground. One is the origin of a railway node where several lines crossed and the coal of Sorachi was sent out to the ports, holding the old layer of a railway town. The other is the memory of a marshalling yard that handled as many as two thousand cars a day and was said to be the largest east of Tokyo, keeping a character that mirrors the scale of the era of coal. And the position at the eastern edge of the Ishikari Plain gives this town the particular structure of a keystone linking the various parts of Sorachi with the ports.

From a post-town ground by the hot water, to a railway node gathering coal, and on to a town after the marshalling yard ended its role. Several railways carrying the coal of Sorachi to the ports crossed at the eastern edge of the Ishikari Plain. Iwamizawa prospered not because it dug coal, but because that coal always passed through here — a town raised as the keystone of a flow grows just as quiet as the flow thins.

Lay out Iwamizawa’s numbers and the indicators of a town that carried the era of coal, shrinking, line up: post-annexation population decline, an aging rate of 36.4%, a household-with-children rate of 16.0%, a fiscal capacity of 0.38. But what I (Atlas) want to note first through the eye of accounting is the fact that the step in population is due to the 2006 annexation of the village of Kitamura and the town of Kurisawa. The 85,029 of 2000 is the figure of the former Iwamizawa-shi alone, and cannot simply be joined for reading with the 90,145 of 2010 that added the two municipalities. Reading the slope of decline — some ten thousand lost in the ten years after annexation — is the proper course.

On that basis, what can be said outright is that this town was not a town that dug coal, but a town that “passed” coal through. Iwamizawa itself did not hold a large mine. The coal dug across the Sorachi region gathered here without fail on its way to the ports, was sorted, and was sent out. The marshalling yard where two thousand cars a day came and went was the very scale of that point of passage. So when the mines of Sorachi closed and the flow of coal thinned, Iwamizawa lost its footing before the digging towns did, but no less surely. A town prosperous upon a passing flow loses its very grounds for prosperity once the flow stops. The figure of a Fiscal Capacity Index of 0.38 is the body warmth of a town that had leaned not on its own resource but on the flow of others’ resources, after it lost that flow. A node is a node only while there is something to link.