Places that used to be sea. Trace reclaimed land through aerial photographs and maps

Published: August 11, 2026 / About 14 min read

Places where only the sea surface remains as you go back through the eras

When you lay old aerial photographs over a town, there are places where no roads or buildings can be found and only sea surface or sandy beach appears all over. These places are land born from reclamation. As you step through the eras, in one of the eras lots enclosed by straight seawalls suddenly appear on the sea. Unlike natural land, which spreads by tracing the terrain, the outlines of reclaimed land are made of straight lines as if drawn with a ruler and right angles. This difference in shape is the first clue for telling reclaimed land apart from the photographs alone.

Besides the outlines, there are other features you can read from the photographs. Inside the lots, roads run in a grid and the blocks are the same size. Outside the seawalls, the water is dug out as shipping channels and anchorages, and cargo-handling cranes and transit sheds line the quays. Because reclamation proceeds by adding lots offshore, another common point is that even on one island, housing and commercial facilities tend to gather on the inland side and logistics facilities on the offshore side.

Where did the soil for reclamation come from?

Turning sea into land takes an enormous amount of earth and sand. The sources fall broadly into three. The first is soil from cutting away inland hills and mountains, and because graded land also remains on the side that was cut, one project gives birth to two towns. The second is dredged soil from digging out shipping channels and anchorages, so the work of deepening the port and the work of making land proceed at the same site. The third is the garbage and surplus construction soil that cities produced. If the source of the soil differs, the time reclamation is completed and the character of the facilities placed on top also change.

Yumenoshima / Shinkiba is land known as an example of the third. Reclamation Site No. 14 in Tokyo Bay was filled as a final disposal site for garbage, and on the land where filling was finished, timber storage ponds, timber-related businesses, and a park were placed. As of 2026, three lines serve Shinkiba Station: the JR Keiyo Line, the Tokyo Metro Yurakucho Line, and the Rinkai Line. The texture value of the photographs has increased from 17.8 to 45.2.

Tokyo Bay and Ise Bay, where the outlines were fixed before 1989

At Toyosu, the outline of the island is almost fixed by the time of the photograph from around 1936-42. The main use of the land was a shipyard, and the 1961-69 photograph also shows the large docks and factory roofs of Ishikawajima-Harima Heavy Industries in rows. Toyosu Station on the Yurakucho Line opened in 1988, and LaLaport Toyosu opened on the former shipyard site in 2006, where a dock from the shipyard era remains on the site as a waterside space. In 2018, the wholesale market moved here from Tsukiji. If you compare the 1961-69 image with the image as of 2026, the texture value of the photographs increased from 16.8 to 40.7. In terms of land use, the share of built-up area within a radius of 500 m expanded from 53% in 1976 to 78% in 2021.

Tennozu is also reclaimed land whose outline is fixed in the photograph from around 1936-42. It was land of warehouses and factories surrounded by canals, but Tennozu Isle Station of the Tokyo Monorail was added in 1992 and a station of the Rinkai Line in 2001, and it became an area where shops, halls, and office buildings converted from warehouses gather. The texture value of the photographs has increased from 19.6 to 38.3. While the shape of the canals stayed the same, only the things inside them were replaced.

The photographs of Kinjo-futo teach that reclamation is not work that ends in one go. The Port of Nagoya in 1945-50 is still sea surface, there is still no land in 1961-69, and the same position is a tidal flat with the tide out. Pentagonal land appears for the first time in 1974-78, and each time you advance the photographs, to 1979-83 and 1987-90, the quays extend further offshore. The texture value of the photographs changed from 13.2 to 38.7.

From gun batteries of the late Edo period to a town of broadcasters

The name of Daiba comes from the Shinagawa Daiba, built in Edo Bay after Perry's arrival in 1853. Of the artificial islands built as gun batteries, No. 3 Daiba remained as a park and No. 6 Daiba as an island left untouched. In the photograph from around 1936-42, most of this area is still sea surface. Its form as the Waterfront Subcenter took shape after 1989: the Rainbow Bridge opened in 1993, a new transit line linking Shimbashi Station and Ariake Station opened in 1995, and in 1997 the head office of a television station moved here. The texture value of the photographs has increased from 10.6 to 32.7.

Next door, the framework of the town of Ariake was formed by the opening of the new transit line in 1995 and the opening of Tokyo Big Sight in 1996. The elevation at the center is 9.1 m, on the high side for reclaimed land. The texture value of the photographs increased from 14.7 to 36.5. In terms of land use, the share of built-up area within a radius of 500 m expanded from 8% in 1976 to 68% in 2021.

Yokohama, where shipyards and freight yards were replaced by blocks

The 1961-69 photograph of Minato Mirai shows the docks of the Yokohama Shipyard of Mitsubishi Heavy Industries and the freight yard of Takashima Station of Japanese National Railways. Construction of the Minato Mirai 21 project began in 1983, Yokohama Landmark Tower opened in 1993, and the Minatomirai Line opened in 2004, and one of the docks was preserved as a plaza. Because land added by reclamation and the original shipyard site are combined, the way to read the photographs differs from that of a brand-new artificial island.

Because this is land where a shipyard and railway land were replaced as they were, the outlines of the old sites also remain in the shapes of the lots. The texture value of the photographs increased from 16.7 to 40.7, and the elevation at the center is 3.0 m. In the photographs from the shipyard era, the rectangles of the docks, ship hulls, and the shadows of cranes occupy the center of the frame.

Kobe, where soil from cut mountains was carried to the sea

Port Island is sea surface in the 1945-50 photograph. The City of Kobe cut away inland hills and built the island by carrying the soil to the sea on belt conveyors. Construction began in 1966, the first phase was completed in 1981, the Port Liner opened and an exposition was held in the same year, and in 2006 Kobe Airport was added on the sea. The hills that supplied the soil were graded as Suma New Town (Myodani), and the land that was cut and the land that was filled remain as a pair. The texture value of the photographs grew fivefold, from 8.3 to 42.3.

Rokko Island is the second artificial island built offshore by the same method. The 1945-50 photograph shows only sea surface, and reclamation began in 1972. The Rokko Liner opened in 1990, and apartment buildings and commercial facilities are placed in the center of the island, with container piers and logistics facilities around its edge. The texture value of the photographs increased from 13.4 to 42.3, and the elevations, 4.6-5.9 m, are almost uniform within the island.

Kobe Harborland is land at the edge of the sea in direct contact with the city area. The town opened in 1992, and in 2001 a station of the Kobe Municipal Subway Kaigan Line was added. The elevation at the center is 2.0 m, and the texture value of the photographs has increased from 17.9 to 47.3. Unlike an artificial island, it does not need to be reached by a bridge or new transit, and as reclaimed land you can walk into from the side of Sannomiya or Kobe Station, it differs in character even within the same Kobe.

Land in Osaka Bay drawn in by an airport and an exposition

Rinku Town is still sea even in the 1984-86 photograph. Kansai International Airport opened in September 1994, and buildings such as Rinku Gate Tower Building (1996) went up on the reclaimed land on the opposite shore. It is an example where even the town planning on the opposite shore moved on the same timeline, matched to the scheduled opening date of a single facility, the airport.

No land appears at Cosmo Square in any of the photographs from around 1928, from around 1936-42, or from 1961-69. At the northwestern tip of Sakishima, the Asia and Pacific Trade Center was completed in 1994, and a 55-story skyscraper (named Sakishima Cosmo Tower as of 2026) in 1995. The mean pixel difference between the 1961-69 photograph and the photograph as of 2026 is the largest value among the listed locations.

Within the same Osaka Nanko, Nanko Port Town is reclaimed land for housing. The photograph from around 1928 shows no land in this area, and in 1981 the Nanko Port Town Line opened and it became a town where mid-rise and high-rise apartment buildings, schools, and parks were laid out according to plan. The texture value of the photographs increased from 8.8 to 48.4.

Seashores that were tidal flats and bathing beaches

In the 1945-50 photograph of Kaihimmakuhari, the shoreline runs near Makuhari-cho on the inland side, and the place where the station stands is on the sea. It was an area where shallow beaches crowded with clam diggers spread out, and after reclamation in the 1970s, Kaihimmakuhari Station on the JR Keiyo Line appears in 1986 and Makuhari Messe in 1989. The texture value of the photographs increased from 7.6 to 42.2.

At Chiba Minato too, in 1945-50 the water's edge was around Nobuto and Shinden-cho. The reclaimed land of the Port of Chiba appears in the photographs in 1961-69, and Chiba Port Tower opened in 1986. The share of built-up area within a radius of 500 m expanded from 25% in 1976 to 70% in 2021.

Maihama is sea surface off Urayasu in the photograph from around 1936-42. Tokyo Disneyland opened in 1983 on land born from reclamation, and Maihama Station on the JR Keiyo Line was set up in 1988. The texture value of the photographs has increased from 10.5 to 40.1. The division of the lots, with large facilities on the sea side and housing on the inland side, can be read clearly in the photographs too.

The sandy beach of Momochihama was where people of Fukuoka came to swim. In the 1961-69 photograph too, the north side of Nishijin is sand and sea. Fukuoka Tower was completed in time for the 1989 exposition, and a ballpark was built at Jigyohama in 1993. The grading of Island City came even later: in the 1987-90 photograph, the area around Teriha is still Hakata Bay and the Wajiro tidal flat, and the texture value of the photographs rose from 3.9 to 28.9.

What appears in the oldest photograph

Even among areas of reclaimed land, the eras you can go back to and the things that appear in that photograph differ by location. If the oldest photograph shows only sea surface, reclamation was later work; if lots already appear, that land is reclaimed land born in an even earlier era.

The 1980s to the 2000s, when town openings and line openings followed one another

The birth of towns on reclaimed land was decided by the openings of railways and new transit lines and by the opening of expositions and large facilities. People did not move in just because the land was finished, and the look of the photographs changes at the boundary of the year the station opened.

The land price records did not point in the same direction

The official land prices (Chika Koji) around reclaimed land move in different ways depending on when the land was graded and what it is used for. Residential land near Toyosu rose from 429,000 yen per square meter in 2012 to 1,160,000 yen in the 2026 publication. Residential land at Jigyohama fell gently from 240,000 yen in 1999 to 217,000 yen in 2011-2012, then turned up, and stands at 441,000 yen in the 2026 publication. On the other hand, residential land at Goshoyama-cho near Minato Mirai fell from 435,000 yen in 1993 to 249,000 yen in 2012, and is 336,000 yen in the 2026 publication. Residential land on the inland side of Rinku Town also fell from 141,000 yen in 1999 to 62,100 yen in 2014-2015, and was 72,000 yen in the 2026 publication. Even among areas of reclaimed land, land adjoining the center of a large city and the suburban waterfront draw completely different lines.

Uses other than housing show yet another pattern. The office and warehouse land on Port Island went from 83,000 yen in 2015 to 185,000 yen in the 2026 publication, and the warehouse land in Nanko from 89,000 yen in 2013 to 198,000 yen in the 2026 publication, both more than doubling. The movement overlaps with the period when demand for logistics facilities is said to have gathered on reclaimed land along the bay. Residential land at Tatsumi near Shinkiba went from 354,000 yen in 2013 to 694,000 yen in the 2026 publication, and residential land at Nobuto near Chiba Minato from 200,000 yen in 2013 to 360,000 yen in the 2026 publication.

Check with the elevation and by stepping through the eras

The elevations of reclaimed land are uniformly low. Toyosu is 2.4 m at the center, Momochihama 1.9 m, Kobe Harborland 2.0 m, Ukishima / Tonomachi King Skyfront 0.8 m, Bannosu (Sakaide) 2.7 m, and Mizushima Waterfront (Kurashiki) 2.8 m. On the other hand, reclaimed land made in later eras can show high values, such as Ariake's 9.1 m. The order suggests that the height required in the design of reclamation changed over time. For assumptions such as flooding in lowland areas, the published materials of each local government are gathered on the Hazard Map Portal Site of the Ministry of Land, Infrastructure, Transport and Tourism.

On the photograph side, the one photograph in which land appears is the record of the birth of each town. If you go back and forth between three eras, the era when only the seawalls were built and the inside is blank, the era when roads were drawn in the lots, and the era when buildings filled them, you can see how many years it took that land to become a town. Look for that photograph on the comparison page.

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