Towns born by cutting away mountains. Traces of new town grading

Published: August 11, 2026 / About 15 min read

Cut the ridges and fill the valleys to make flat ground

The grading that builds a town on hills proceeds by combining cut, which shaves off the high places, and fill, which piles earth onto the low places. Because neither roads nor housing lots can be placed on a slope as it is, the ridges are cut to make terraced flat ground, and the valleys are filled back by putting the cut soil into the valley lines. If the amounts of cut and fill balance, the soil stays within the site, but if the cut side is larger, the surplus earth and sand has to be carried out. If you step through the eras of the aerial photographs, you find eras in which the middle of this work appears as white bare ground.

The work does not advance all at once from the edge of the site. First, roads for carrying earth and sand extend onto the hill, trees are cleared in part of the area, and the flat ground spreads from there. So in photographs taken during grading, woodland, bare ground, and blocks whose lots have already been divided sit side by side in the same frame. If you follow which parts are still woodland and how far the flat ground reaches, you can read even the order in which that hill was cut.

Kobe, where the cut soil filled the sea

The City of Kobe is an example that designed even the destination of the earth and sand as part of one project. In Suma New Town, which includes Myodani, the city cut the hill forests of Suma on a large scale and sent the excavated earth and sand to the sea on belt conveyors. The soil that was carried became material for reclamation, and towns were born at the same time on the hill side and the sea side. It was a project called "the mountains go to the sea". The elevation of Myodani is about 98 m, and Myodani Station on the municipal subway opened in 1977.

If you look at the side that received the soil, the difference in height stands out. Construction of Port Island began in 1966, the first phase was completed in 1981, and the Port Liner opened in the same year. Its elevation is 3.7-5.7 m. Reclamation of Rokko Island began in 1972, the Rokko Liner opened in 1990, and its elevation is 4.6-5.9 m. The roughly 98 m on the hill and the 5 m or so at the sea's edge are the two ends that shared the same soil. The view from the side of the towns born on the sea is collected in Towns that used to be sea. Trace reclaimed land through aerial photographs.

Seishin-Chuo in the west of the City of Kobe is also a town opened by grading of the same lineage. It is on a plateau at an elevation of about 90 m, and the 1979-83 photograph shows white ground as grading advances, while the 1984-86 photograph shows the outlines of the blocks. The Seishin Line of the municipal subway was extended here in 1987. If you go back to the 1961-69 photograph, a farming village in the hills dotted with irrigation ponds spreads out.

Japan's first large-scale new town was also on a hill

The area of Senri-Chuo held its town opening in 1962 as a pioneer of new town development in Japan. The elevation at the center is 66.6 m, on land graded from the ridges and valleys of the Senri Hills. The 1961-69 photograph shows hills in the middle of grading and newly built blocks in the same frame. The contrast between parts where bamboo groves and fields remain and parts where residential buildings stand in rows is condensed into this one photograph.

Senri-Chuo later became a transport hub with the extension of the Kita-Osaka Kyuko Railway and the opening of the Osaka Monorail. Because Senri-Chuo Station is underground, the elevation shown is the value of the ground surface above the station. The texture value of the photographs increased from 17.2 in 1961-69, the baseline for comparison, to 51.1 as of 2026. The official land price (Chika Koji) of residential land at Shinsenri-nishimachi near Senri-Chuo fell from 440,000 yen per square meter in 1995 to 232,000 yen in 2005, and was 353,000 yen in 2026.

The grading that followed on the hills of Osaka and Nagoya

Senboku New Town (Izumigaoka) held its town opening in 1967, and Izumigaoka Station on the Semboku Rapid Railway opened in 1971. The elevation at the center is 71.5 m and the measuring point to the south is 84.6 m, and the relief of the Senboku Hills remains within the town. In the photograph from around 1936-42 the area is hills and farmland, and from 1974-78 to 1984-86 the blocks fill the frame.

At Kozoji New Town, occupancy began in 1968 on a scale said to be among the largest in the Chubu region. The elevation at the center is 91.5 m, and the texture value of the photographs has increased from 11.6 to 41.7, placing it on the side where the frame before grading was uniform. The JR Chuo Line and the Aichi Loop Line run nearby. The official land price of residential land at Iwanaridai rose from 71,800 yen in 2016 to 76,000 yen in 2026.

Two Tokyo towns cut from the Tama Hills

In Tama New Town, whose core district is Tama Center, occupancy began in 1971 in the Suwa and Nagayama districts. The 1974-78 photograph of Tama Center shows grading in progress, and by the 1987-90 photograph the core district in front of the station has taken shape. The elevation at the center is 88.6 m, the measuring point to the south 103.8 m, and the west 98 m. Later the Tama Toshi Monorail was added, and it became a station where several lines meet. The official land price of residential land at Ochiai fell from 251,000 yen in 2002 to 210,000 yen in 2012-2013, and was 266,000 yen in 2026, which means it took 24 years to rise above the original level.

Minami-Osawa lies on the west side of the same Tama New Town. The elevation at the center is 115 m, and the measuring points in the four directions are high at 120-127 m; the terrain is one where the station and the blocks were placed in a low spot surrounded by ridges left uncut. Minami-Osawa Station on the Keio Sagamihara Line opened in 1988, and a university campus and large commercial facilities line up around the station. The official land price of residential land fell from 203,000 yen in 2001 to 163,000 yen in 2005-2006, and was 227,000 yen in 2026.

The hills of Yokohama, opened along a whole private railway line

Tama Plaza is a town opened as the core of Tokyu's Tama Den-en-toshi plan. The Den-en-toshi Line opened in 1966, and in the 1945-50 photograph paddies in yato valleys and coppice woods spread out, with no sign of the town yet. The elevation at the center is 54 m, and the texture value of the photographs increased from 15.3 to 42.6. The official land price of residential land at Shin-ishikawa has risen from 430,000 yen in 2016 to 644,000 yen in 2026.

At Aobadai on the same line, a long record of land prices remains. The official price of residential land rose from 236,000 yen in 1983 to 785,000 yen in 1988, fell to 285,000 yen in 2004-2005, and was 409,000 yen in 2026. The movement of more than tripling in five years and then falling back to nearly a third over the following 16 years remained as the record of a residential area on a hill. The elevation at the center is 37.8 m.

On the south side of the City of Yokohama, at Yokodai you can go back through six eras, from 1945-50 to FY2007. Against 38.5 m at the center, the measuring point to the north is 49.7 m, the south 57.5 m, and the west 55.6 m. All four directions are 8-19 m higher than the center, which suggests that the station and the blocks were placed by choosing a valley line. At Center-Kita in the north of the city, the 1974-78 photograph shows bare ground under grading. It later became a station served by two lines of the municipal subway, and commercial facilities gathered in front of the station.

The hills before grading were uniform in the photographs

If you turn the fineness of what appears in the photographs into numbers as the texture value, a common tendency appears in the towns made by grading hills. Seishin-Chuo increased from 10.9 to 38.0, Myodani from 15.9 to 39.4, Tama Center from 12.5 to 39.4, Minami-Osawa from 16.7 to 37.6, and Center-Kita from 17.3 to 33.1. The low starting values are the reverse side of the fact that the frames before grading were filled with coppice woods and mountain forests and had little visible relief. On land where fields and villages came first, the starting values are higher, and the difference from after the town was built comes out smaller.

Kozoji's 11.6 is a starting point on the low side, alongside Seishin-Chuo's 10.9. Conversely, Senri-Chuo has grown to 51.1 as of 2026, and the density of residential buildings and commercial facilities shows directly in the number.

Leveling does not erase the relief

Because grading is the work of replacing slopes with steps, the differences in level remain within the town. At Center-Kita, the station area is 23.7 m, the measuring point to the north 35.4 m, and the east 38.6 m, so it holds a difference in height of about 15 m within a range of a few hundred meters. Minami-Osawa is about 115-127 m, and Tama Center is 88.6 m at the center against 103.8 m to the south and 98 m to the west. You meet slopes when you walk between the residential districts not because the terrain became flat, but because it was rearranged into steps.

The range of height differs by town. Hokusetsu Sanda New Town (Flower Town) is 189.5 m at the center and 205.9 m at the measuring point to the south; it is the town opened at the highest place in this list. Heijo New Town (Takanohara) is 55.6 m at the center against 68.9 m to the east and 71.2 m to the west, so the surroundings are one step higher. Rakusai New Town is 62.6 m at the center, 72.4 m at the measuring point to the west, and 56.9 m to the east, and its blocks are placed on a slope that drops about 15 m from west to east. The tilt of the values in the four directions shows that it is land cut from hills partway down from the mountains on the west side toward the Kyoto Basin.

The elevations shown are measured values of the ground surface and do not show assumptions about flooding or earthquakes. For the assumptions for each piece of land, refer to the published materials of each local government through the Hazard Map Portal Site of the Ministry of Land, Infrastructure, Transport and Tourism.

A photograph from during grading tells the age of a town

The era in which bare ground appears shifts from town to town. For Myodani and Center-Kita the photographs of 1974-78, for Seishin-Chuo those of 1979-83, and for Minami-Osawa those of the 1980s fall in the middle of grading, and at Tama Center, after grading in 1974-78, the core district in front of the station appears in the 1987-90 photograph. If you see in which era white ground appears, you can roughly narrow down when the hill of that town was cut.

Makomanai is land where the athletes' village and competition venues were placed for the 1972 Sapporo Winter Olympics. The 1961-69 photograph shows the vast open land of a livestock breeding farm, and the 1974-78 photograph shows a residential town and sports facilities side by side. The elevation at the center is 94.4 m, and the mean pixel difference between the photograph of the oldest era and the photograph as of 2026 was 27 on a scale of 0-255. The drop from open land to town shows in this value.

Flower Town is the opposite example. The photographs you can go back to at this location are two, 1961-69 and 1974-78, and the town appears in neither. The town opening was in the 1980s and the Kobe Electric Railway Koen-Toshi Line opened in 1991, so all the photograph eras fall before grading. The City of Sanda is said to have had a period from the late 1980s into the 1990s when its rate of population growth was the highest in the country, and the town that took in that growth never appears in the photographs.

Thirty years of town openings and station openings

People do not start living in towns opened by cutting hills just because grading is finished. A common point of this kind of town is that the start of occupancy and the year the railway arrived come at separate times. If you lay them over the eras of the photographs, they become markers for measuring the age of the town.

The land price records split town by town

The shape of the official land prices of the towns opened by cutting hills changes with the year the record began. At points whose records continue from the 1980s, a line that rises sharply and then falls remains, while at points whose records began in the 2000s or later, lines with a small range of ups and downs line up. Residential land at Ryugadai near Myodani rose to 425,000 yen in 1991, fell to 136,000 yen in 2011-2013, and was 163,000 yen in 2026. Residential land at Takenodai near Seishin-Chuo went from 135,000 yen in 2010-2013 to 170,000 yen in 2026, and the area around Center-Kita from 340,000 yen in 2020 to 433,000 yen in 2026.

At Makomanai, the highest year in the record up to the 2026 publication was 2026. This means there are also cases where residential land made by grading hills extends its record half a century after the town opening. Conversely, residential land at Oeda Kita-Fukunishi-cho near Rakusai New Town went from 148,000 yen in 2016 to 148,000 yen in 2026, and its swing over the 11 years stayed within a range of 5,000 yen. The highs and lows in the next table are the highest and lowest within the range of years for which records remain near each point.

Go back and forth between three eras: before grading / during grading / blocks

When you read a town born by cutting away mountains, try going back and forth between three eras: before grading, during grading, and after the blocks have set. In the eras before grading you can make out the shapes of the ridges and valleys, and in the eras during grading the direction of the cut slopes and the valley lines not yet filled with soil. If you switch to an era after the blocks have set, you can see which streets and parks those valley lines became.

Comparing the elevations in the four directions is also a clue. At a point where the surroundings are one step higher than the center, the town is placed inside ridges left uncut. If you look at Kobe's two artificial islands and the hill towns in a row, you can also confirm that the cut soil and the filled soil were the two ends of the same project. Step through the eras on the comparison page, and look for the photograph in which that hill turns into a town.

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