Senboku New Town (Izumigaoka) about 60 years ago and today

History of Senboku New Town (Izumigaoka)

Heading south from central Osaka and passing through the urban area of Sakai, you reach hills where fine ridges and valleys fold over one another in many layers. These are the Senboku Hills. Water was hard to bring for opening paddies and there was no large stretch of flat land, so for a long time this was a place where terraced paddies in each valley alternated with woods on the ridges. Izumigaoka was placed in one corner of these hills as the first block, and Izumigaoka Station on the Semboku Rapid Railway Line is at its center. The moment when the surface of the hills is replaced wholesale fits into a single switch among the five past eras from c. 1936-42 to 1984-86.

A valley, the lowest point of the hills

The five elevation points show that this location is not on high ground in the hills. The center is 71.5 m, and the north at 75.5 m, the east at 81.4 m, the west at 82.9 m and the south at 84.6 m are all higher. It is a valley within the hills, lower than all four sides. When the town was set on the hills, it was this line of the valley that was chosen as the place to run the tracks and the station. On land where the key to development is cutting the ridges, filling the valleys and making flat surfaces, the station was placed at the lowest point and the residential blocks on the side of the ridges that were cut out. The axis of the town is at the bottom of the valley.

Hills of terraced paddies and woods

The oldest aerial photograph, from around 1936-42, has an image only in roughly the upper half. Below a diagonal edge rising gently to the right, a gray surface with no shading continues to the bottom edge. Even the north side that is shown is enough to read the character of the land. The ridges are dark woods, and in the valleys between them long, narrow terraced paddies form layers. Small paddies curving along the contour lines continue to the far end of the valleys, and several black water surfaces, where valleys were dammed, are dotted about. Only the left edge (west) of the frame is flat, showing a fine grid of paddies and a hamlet whose rows of houses extend in a single line along a road. One more thing that catches the eye is a single clear line crossing the upper right of the frame diagonally. The roads inside the hills are all narrow, and only this line stands out as one of a different width. This shows that a route over the hills had been laid out early on.

In the 1961-69 photograph the whole frame is present, and you can see into the interior of the hills. The valleys branch into many arms, and terraced paddies are carved into nearly all of them. The steps of the paddies curve along the contour lines, and the relief of the hills appears directly as lines. The rises dividing one valley from another are unbroken woods, and the places where people live are limited to the mouths of the valleys and the flat land to the west. The terraced paddies are carved to the very end of the valleys, and almost no surface in the hills is left over as flat ground.

In the same 1961-69 photograph, notice the upper middle and the upper right of the frame. Several surfaces, brighter and whiter than their surroundings, open up between the woods and the terraced paddies. They are bare ground stripped of vegetation, and their outlines match neither the lots of the paddies nor the shape of the valleys. You cannot tell from a single photograph what the bare ground was for, but you can read that human hands had begun to work on the surface of the hills. In the photograph of this era there are still no blocks and no railway.

Blocks set on the hills

In the 1974-78 photograph, the hills become a town in one piece. Nearly the whole frame is filled with residential areas, and curving streets wind around, tracing the shape of the ridges. The straight line running diagonally through the center from the lower left to the upper right is the railway, and beside it a long, narrow station structure meets a road that winds in a ring. Northeast of the station there are a circular structure and a wide paved surface, a shape that looks like a plaza placed at the center of the town.

The same photograph also shows how the town was divided by type. The west half is blocks of detached houses with small roofs lined up finely, and the way the streets curve follows the direction of the valleys. From the center to the east, mid-rise residential buildings of the same shape and the same orientation repeat in rows. At the bottom of the valley that was terraced paddies in the 1961-69 photograph, a long, narrow water surface has been left in the same position. To the south (bottom) of the hills, woods and valley paddies are still wide, and the edge of the blocks is cut off cleanly at the mouth of the valleys.

In this era, do not overlook the brown surface spreading on the east side. Land where development has finished and only the lines of the lot divisions have been drawn, with no buildings yet, continues like a band outside the blocks. The distribution of this bare ground shows that the town was not built all at once but spread out by filling in from west to east.

Shapes left in the ponds and valleys

In the 1979-83 photograph, that brown surface begins to fill with buildings. Buildings with large roofs and wide paved surfaces gather around the station, and the rows of mid-rise residential buildings extend east and southeast. By 1984-86 there are almost no gaps left even in the eastern blocks, and the trees planted along the streets come to be seen as rows of dark green. In the upper left of the frame a sports ground with a reddish-brown running track appears, showing that besides residential buildings and detached houses, places where people gather were also put in place. Even so, the valleys in the south of the frame are still paddies and woods in this era.

In the latest aerial photograph too, the framework of the town overlaps well with 1984-86. The shape of the streets and the positions of the rows of residential buildings have hardly changed. The change is in the area around the station: the circular structure seen in 1974-78 is gone, and in its place buildings with large roofs and wide rooftop surfaces stand side by side. Within the blocks too, there are places where the orientation and size of buildings have changed, suggesting that rebuilding progressed over half a century.

On the other hand, the shape of the hills themselves remains. The long, narrow water surface in the center is in the same position and of the same shape as in the 1961-69 photograph, and dark green woods surround it. The pond that dammed the valley and the low ground of the valley floor that received its water have been carved out as a green band inside the town. Because surfaces where valleys were filled and surfaces where ridges were cut alternate from block to block, the way rainwater collects is not uniform either. The City of Sakai's hazard map shows the areas that call for caution location by location. It is worth opening it together with the lines of the valleys that can be read from the photographs. Besides the center, water surfaces also remain in the upper right and along the left edge of the frame. In the south of the frame, paddies on the valley floor also appear in the latest aerial photograph, and outside the edge of the hills the land is still used as farmland. The lines of the valleys show through the cut hills.

For a residential site in Takeshirodai 2-chome, about 620 m from the location, the value per square meter was 107,000 yen in 2016, when the record begins, and 120,000 yen in 2026. In this location's record up to the 2026 official land prices (Chika Koji), the lowest value is 107,000 yen from 2016 to 2021 and the highest is 120,000 yen at the end point, 2026, a gentle upward trend. It is a series that reads as the values of a residential area where a long time has passed since the town opened and rebuilding is progressing.