Sixty years of the three great new towns: Senri, Tama, and Senboku

Published: August 11, 2026 / About 14 min read

Senri in northern Osaka Prefecture, Tama in western Tokyo, and Senboku in southern Osaka Prefecture are named as large-scale new towns often mentioned together for their scale and pioneering role. All of them are towns built by grading hills from the 1960s into the 1970s, and if you step through the aerial photographs in order of era, the process in which woods and valleys are replaced by grid blocks within a little more than ten years shows in the frame just as it happened. While the steps of grading are very similar, the series of official land prices (Chika Koji) traced separate shapes to the extent that the years the towns opened were staggered. This article adds Kozoji in the Chubu region and lines up three measures, the eras of the photographs / the height of the hills / the price records, to read the differences among the five towns.

Why the three towns are discussed together

Senri was planned as Japan's first large-scale new town, and its first residents moved in in 1962. Until then, the supply of residential land had mostly taken the form of extending the edges of existing urban areas little by little. In Senri, the hills were acquired as a single area, and residential districts / schools / commercial cores / trunk roads were drawn into the plan from the start before the earth was moved. The design idea of first deciding the residential districts as the units of daily life and assembling the whole town from their combination is said to have become the model for later large-scale development.

Senboku continued the same method with the same Osaka Prefecture as the developer, moving the area to the hills spreading south of the City of Sakai. Tama advanced with several developers, Tokyo and the Japan Housing Corporation among them, sharing out the area, and it became one of the largest new towns in Japan by area. Kozoji is a town that the Japan Housing Corporation built as a base for the housing supply of the Chubu region. The developers and regions differ, but the technique of rearranging hills of intricate ridges and valleys into a set of flat areas is shared. That is exactly why they look much alike in the aerial photographs, and only the price records drift apart town by town.

The era in which the first blade cut into the Senri hills

The area of Senri-Chuo is the location whose photographs go back to the oldest era among the hill new towns listed. Two eras remain, from around 1936-42 and from 1945-50, and you can confirm that a farming landscape of bamboo groves and valley land spread over the hills before grading began. In the following 1961-69 photograph, the scene becomes a transitional one in which ground exposed where the grading blade cut in mixes with green space not yet touched. Since the town opened in 1962, this era captures the very moment the town was born.

If you step on through 1974-78, 1979-83, and 1984-86, the blocks firm up, and the commercial core and the skeleton of the residential areas become distinguishable. The railway was extended to Senri-Chuo in time for the world exposition of 1970, and the town on the hill was linked directly with the city center. Because the station at Senri-Chuo is underground, the elevation listed shows the height of the ground surface. The mean pixel difference between the 1961-69 photograph and the image as of 2026 is 25.6, and the texture value, which shows how finely detailed the photograph is, rose from 17.2 to 51.1, about three times. Among the five towns, this is the location with the largest value after grading.

The Sakai hills that Senboku took over

Izumigaoka opened as a town in 1967, and Izumigaoka Station on the Semboku Rapid Railway opened in 1971. Work started five years after Senri, but the ridgelines of the hills and farmland still remain in the 1961-69 photograph, and the bulk of the change appears in the eras from 1974-78 on. The texture value goes from 23.3 to 38.5, a gentler increase than in Senri. Because the lots of farmland and the old village paths were already carved into the frame before grading, the difference from after it became a town comes out smaller.

The era from around 1936-42 also remains at Izumigaoka, but there is no 1945-50 era. The sequence of photograph eras differs from location to location, and the way of reading also changes depending on whether the two eras you want to compare are both available. Senri has six, Izumigaoka five, and Kozoji four, and the number of past eras itself shows how thick each town's record is. In a town with few eras, a comparison that directly spans the time before and after the town opened is difficult, so you read the change in the photographs while filling it in with the price and elevation records.

The largest town, spread over the Tama Hills

Residents began moving in at Tama Center in 1971. The 1974-78 photograph is in the thick of grading, with cut slopes and graded flat areas mixed together. The mean pixel difference comparing 1961-69 with the latest image is 18.1, on the small side among the five towns. On land that was dark and uniform woods before grading, the difference in brightness itself from after it became a town does not easily come out large. In 1974-75 two private railways reached Tama Center, and the town on the hill was linked toward the city center. The line listed is the Tama Toshi Monorail Line.

The area of Tama New Town spans four cities: Tama / Hachioji / Inagi / Machida. Because a single town was planned across administrative boundaries, the order of development differed by residential district, and the towns opened in turn from the east side to the west side. While Senri and Senboku were completed together on one set of hills, in Tama the age of the town differs by more than ten years between one end of the area and the other. Even when grouped under the name of the same new town, the time when change is visible as you step through the aerial photographs differs from place to place.

Minami-Osawa came even later within the same Tama New Town, and Minami-Osawa Station on the Keio Sagamihara Line opened in 1988. The outline of the town settles in the photographs from the 1984-86 and 1987-90 eras, and earlier photographs keep the slopes where grading is advancing and the terrain of yato valleys. The elevation at the center is 115 m, and the surrounding measurement points reach up to 127.3 m, placing it on the high side among the listed locations. You can read from the sequence of photographs that, even for two locations sharing the name of the same new town, the eras in which the towns took shape are more than ten years apart.

The uniform starting point that Kozoji shows

Kozoji New Town, planned as one of the largest in the Chubu region, began receiving residents in 1968. The texture value has risen from 11.6 to 41.7, and its feature is that its value before grading is the smallest of the five. The relationship that the more uniform the land before grading, the larger the difference in the numbers shows clearly here. Slopes of continuous woods have no fine pattern in the photographs, so the value is small, and the gap from the value after the blocks and roofs are lined up becomes large.

The nearest station, Kozoji Station, is a junction where the JR Chuo Line and the Aichi Loop Line connect. The elevation at the center is 91.5 m, with 100.4 m in the north and 90.6 m in the south, putting it in the high band next to Minami-Osawa. Even in hill grading, the height of the hills cut out follows the terrain of the region, so each town has a different height band. Kozoji has four photographs, 1961-69, 1974-78, 1979-83, and 1987-90, and the 1984-86 era is missing. A window is empty at the time when the town was being completed.

A shared feature: flat areas set on the ridges

If you line up the five locations, you can read how the step between the center and the surroundings appears. Three locations exceed 10 m, with 13.1 m for Senboku, 15.2 m for Tama, and 12.3 m for Minami-Osawa, while Kozoji is 8.9 m and Senri (4.2 m) stays just under 5 m. In grading that fills valleys and cuts ridges to make flat areas, terraces of different heights are created for each residential district, and those steps remain as traces in both the topographic map and the aerial photographs. This contrasts with reclaimed land, which is evenly flat, and if you set them beside Takashimadaira Danchi (housing complex), a lowland danchi at 3.4 m at the center, you can see that even towns of apartment housing stand on completely different terrain.

Even among hill new towns, the height bands are not uniform. The center of Center-Kita is 23.7 m, and its surroundings range from 22.4 m to 38.6 m. If you take the view that the technique of grading shows less in the height of the hills themselves than in how the difference between the center and the surroundings is formed, the way to read the two cross-section graphs lined up in the elevation section also becomes clear. The number and spacing of the steps can be seen as a record that directly reflects how the residential districts were divided.

The elevations listed are measured values of the ground surface and do not show flood or earthquake scenarios. For the disaster scenarios of each piece of land, refer to the materials published by each local government through the Hazard Map Portal Site of the Ministry of Land, Infrastructure, Transport and Tourism.

Troughs in the official land prices do not come in the same year

The residential land at Shinsenri-nishimachi, Toyonaka, near Senri-Chuo fell from 440,000 yen in 1995 to 232,000 yen in 2005, and in the 2026 publication it is 353,000 yen. If you look only at the endpoints, it is at a level of about 80% of 1995, and the depth of the trough stands out among the hill new towns listed. The fact that the window of the record begins in 1995, and so wholly includes the period in which prices fell greatly, also contributes to this shape.

The residential land at Ochiai, Tama fell from 251,000 yen in 2002 to 210,000 yen in 2012-2013, and in the 2026 publication it is 266,000 yen, above the start of the record. The residential land at Minami-Osawa, Hachioji fell from 203,000 yen in 2001 to 163,000 yen in 2005-2006, and 227,000 yen in 2026 is the highest value in the series up to the 2026 publication. The comparison between these two towns and Senri shows that the order in which the towns opened is not the order of the price troughs. The shape of a series is governed by which period the window of the record covers, not by the age of the town.

For the residential land at Takeshirodai, Minami Ward, Sakai, the window of the record starts in 2016, 107,000 yen continued until 2021, and in the 2026 publication it is 120,000 yen. The residential land at Iwanaridai, Kasugai moved from 71,800 yen in 2016 to 76,000 yen in the 2026 publication. These two series with short windows do not include a period of large falls, so no deep trough like Senri's appears. When comparing the shapes of series, you first need to check that the length of the record window differs from town to town.

The distance to the reference point also differs from town to town. The reference point of Minami-Osawa is 354 m from the location, Izumigaoka's is 616 m, and Senri-Chuo's is 736 m. Even within the same town, the character of the land changes between the station area and the depths of a residential district, so it is not appropriate to compare the height of the series itself between towns as if it were a ranking. You can read the difference in shape: in which year the trough came at each reference point, and how the endpoints changed.

The face before grading that shows in the texture of the photographs

The values on the latest side fall between 37.6 and 51.1, and the way the towns look after they became towns draws close to one another. The difference is large on the old side: between 11.6 for Kozoji and 23.3 for Izumigaoka there is a twofold gap. It is reasonable to read this gap not as a measure of how well each town turned out but as a clue showing what the land was before grading. It is small for woods, and it becomes large when farmland or existing villages are mixed in.

The section on change seen in the share of built-up area also notes how this value changed. If you grasp the value by its position compared with other locations rather than looking at a single number, the features of the hill new town type are easier to understand. If you compare it with reclaimed land locations and former factory site locations, it becomes even clearer that the character of the land before grading is reflected in this value.

What to look at when you step through the eras

The key to reading a new town in aerial photographs is to compare the eras before and after the year the town opened. The boundary where woods switch to blocks is 1961-69 for Senri, 1961-69 and 1974-78 for Senboku, from 1974-78 to 1979-83 for Tama and Kozoji, and from 1984-86 on for Minami-Osawa. If you move the slider of the comparison viewer left and right, the hills and the town swap places within the same frame, and in towns where an era photographed in the middle of grading remains, you can even tell apart the direction of the cut slopes and the places where surplus soil was dumped.

In the elevation section, compare the two cross-section graphs, east-west and north-south. In hill new towns, steplike drops often line up between one flat area and the next, and the positions of the drops correspond to the breaks between blocks in the photograph. The vertical enlargement ratio is stated as "vertical exaggeration ×N", so to avoid misreading the actual size of the steps, it is surest to check the ratio before looking at the shape.

Toward the bottom of a location page there is a guide lining up nearby locations and locations with the same origins. If you move from a hill-grading new town to towns of the same type, and from there cross over to towns on reclaimed land and towns on former factory sites, you can feel how much the difference in the land before grading governs how the photographs look. Stepping through in order of proximity, from Senri to Izumigaoka and from Tama Center to Minami-Osawa, is also an easy way to check the difference in the ages of the towns.

If you go on looking at the five towns in a row, you see that towns made by the same method have different faces only because of the year they began and the way their records remain. The single point that even with the same grading method, the records do not line up is at the heart of the interest of reading the three great new towns side by side.

The prices in this article are actual examples at each point in time and do not reflect market prices after the time of writing.

The prices in this article are actual examples at each point in time and do not reflect market prices after the article was written.