Editing Geography of Japan (section)

==Composition, topography and geography==
[[File:Japan topo en.jpg|thumb|upright=1.2|A topographic map of Japan]]
About 73% of Japan is mountainous,<ref>{{Cite web |title=Statistics Bureau Home Page/Statistical Handbook of Japan 2022 |url=https://www.stat.go.jp/english/data/handbook/c0117.html |access-date=2023-04-14 |website=www.stat.go.jp |archive-date=2021-10-23 |archive-url=https://web.archive.org/web/20211023074041/http://www.stat.go.jp/english/data/handbook/c0117.html |url-status=live }}</ref> with a mountain range running through each of the main islands. Japan's highest mountain is [[Mount Fuji]], with an elevation of {{convert|3776|m|ft|0|abbr=on}}. Japan's forest cover rate is 68.55% since the mountains are heavily forested. The only other developed nations with such a high forest cover percentage are Finland and Sweden.<ref name="worldbank">{{cite web |title=Forest area |url=http://data.worldbank.org/indicator/AG.LND.FRST.ZS?order=wbapi_data_value_2013+wbapi_data_value+wbapi_data_value-last&sort=desc |publisher=The World Bank Group |access-date=2015-10-11 |archive-date=2015-10-16 |archive-url=https://web.archive.org/web/20151016000406/http://data.worldbank.org/indicator/AG.LND.FRST.ZS?order=wbapi_data_value_2013+wbapi_data_value+wbapi_data_value-last&sort=desc |url-status=live }}</ref>

Since there is little level ground, many hills and mountainsides at lower elevations around towns and cities are often cultivated. As Japan is situated in a volcanic zone along the Pacific deeps, frequent low-intensity earth tremors and occasional volcanic activity are felt throughout the islands. Destructive earthquakes occur several times a century. [[Hot spring]]s are numerous and have been exploited by the [[leisure industry]].

The [[Geospatial Information Authority of Japan]] measures Japan's territory annually in order to continuously grasp the state of the national land. As of July 1, 2021, Japan's territory is {{convert|377,973.89|km2|sqmi}}. It increases in area due to volcanic eruptions such as [[Nishinoshima (Ogasawara)|Nishinoshima]] (西之島), the natural expansion of the islands, and land reclamation.<ref name="Geospatial Information Authority of Japan 2022">{{cite web |title=【お知らせ】令和3年全国都道府県市区町村別面積調（7月1日時点）, Reiwa 3rd year National area of each prefecture municipality (as of July 1) |url=https://www.gsi.go.jp/KOKUJYOHO/MENCHO-title.htm |publisher=[[Geospatial Information Authority of Japan]] |access-date=October 15, 2021 |language=ja |date=23 March 2022 |archive-url=https://web.archive.org/web/20220409070834/https://www.gsi.go.jp/KOKUJYOHO/MENCHO-title.htm |archive-date=April 9, 2022}}</ref>

This table shows land use in 2002.<ref name="mlit-2011">{{cite web |url=http://tochi.mlit.go.jp/wp-content/uploads/2011/02/16-02.pdf |title=土地総合情報ライブラリー 平成16年土地の動向に関する年次報告 第2章 土地に関する動向 |publisher=国土交通省 |language=ja|access-date=2007-02-17|url-status=live|archive-url=https://web.archive.org/web/20130120195343/http://tochi.mlit.go.jp/wp-content/uploads/2011/02/16-02.pdf|archive-date=2013-01-20}}</ref>

{| class="wikitable sortable"  style="margin:auto; width:50%;"
|-
! style="width:14%;" class="unsortable"| Forest
! style="width:14%;" class="unsortable"| Agricultural land
! style="width:14%;" class="unsortable"| Residential area
! style="width:14%;" class="unsortable"| Water surface, rivers, waterways
! style="width:14%;" class="unsortable"| Roads
! style="width:14%;" class="unsortable"| Wilderness
! style="width:16%;" class="unsortable"| Other
|- class="vcard" style="text-align:center;"
| 66.4% || 12.8% || 4.8% || 3.6% || 3.4% || 0.7% || 8.3%
|- class="vcard" style="text-align:center;"
| {{convert|251,000|km2|sqmi|abbr=on}} || {{convert|48,400|km2|sqmi|abbr=on}} || {{convert|18,100|km2|sqmi|abbr=on}} || {{convert|13,500|km2|sqmi|abbr=on}} || {{convert|13,000|km2|sqmi|abbr=on}} || {{convert|2,600|km2|sqmi|abbr=on}} || {{convert|31,300|km2|sqmi|abbr=on}}
|}

===Location===
The Japanese archipelago is relatively far away from the Asian continent. Kyushu is closest to the southernmost point of the Korean peninsula, with a distance of {{convert|190|km|mi|abbr=on}}, which is almost six times farther away than from England to France across the [[English Channel]]. Thus, historically, Kyushu was the gateway between Asia and Japan. China is separated by {{convert|800|km|mi|abbr=on}} of sea from Japan's big [[mainland Japan|main islands]]. Hokkaido is near [[Sakhalin]], which was [[Karafuto Prefecture|occupied by Japan]] from 1905 to 1945. Most of the population lives on the Pacific coast of Honshū. The west coast facing the Sea of Japan is less densely populated.<ref name="jpn-places"/>

The Japanese archipelago has been difficult to reach since ancient history. During the [[Japanese Paleolithic|Paleolithic]] period around 20,000 BCE, at the height of the [[Last Glacial Maximum]], there was a land bridge between Hokkaido and Sakhalin that linked Japan with the Asian continent. The land bridge disappeared when sea levels rose in the [[Jōmon period]] around 10,000 BCE.<ref name=Japan>{{cite book |last1=Campbell |first1=Allen |last2=Nobel |first2=David S |title=Japan: An Illustrated Encyclopedia |publisher=Kodansha |date=1993 |page=1186 |isbn=406205938X}}</ref>

Japan's remote location, surrounded by vast seas, rugged, mountainous terrain, and steep rivers, makes it secure against invaders and uncontrolled migration from the Asian continent. The Japanese can close their civilization with an [[isolationist]] [[foreign policy]]. During the [[Edo period]], the [[Tokugawa Shogunate]] enforced the [[Sakoku]] policy, which prohibited most foreign contact and trade from 1641 to 1853.<ref>Ronald P. Toby, ''State and Diplomacy in Early Modern Japan: Asia in the Development of the Tokugawa Bakufu'', Stanford, California: Stanford University Press, (1984) 1991.</ref> In modern times, the inflow of people is managed via seaports and airports. Thus, Japan is fairly insulated from continental issues.

Throughout history, Japan has never been fully invaded or colonized by other countries. The [[Mongol invasions of Japan|Mongols tried to invade Japan]] twice and failed in 1274 and 1281. Japan capitulated only once after nuclear attacks in World War II. At the time, Japan did not have [[nuclear technology]]. The insular geography is a major factor in the isolationist, semi-open, and [[expansionist]] periods of [[History of Japan|Japanese history]].

===Mountains and volcanoes===
{{main|List of mountains and hills of Japan by height}}

The mountainous islands of the Japanese archipelago form a crescent off the eastern coast of Asia.<ref name=loc>{{citation-attribution|1={{Cite book |url=https://www.loc.gov/item/91029874/ |title=Japan: a country study |series=Area handbook series |date=1992 |publisher=[[Federal Research Division]], [[Library of Congress]] |isbn=0-8444-0731-3 |editor-last=Dolan |editor-first=Ronald E. |edition=5th |location=Washington, D.C. |pages=72–84 |oclc=24247433 |access-date=2020-11-02 |archive-date=2021-07-29 |archive-url=https://web.archive.org/web/20210729190534/https://www.loc.gov/item/91029874/ |url-status=live }}|editor-last2=Worden|editor-first2=Robert L.}}</ref> They are separated from the continent by the Sea of Japan, which serves as a protective barrier. Japan has 108 active [[volcano]]es (10% of the world's active volcanoes) because of active plate tectonics in the Ring of Fire.<ref name="volcanoes-japan"/>

Around 15 million years ago, the volcanic shoreline of the Asian continent was pushed out into a series of volcanic island arcs.<ref name="Barnes"/> This created the "back-arc basins" known as the [[Sea of Japan]] and [[Sea of Okhotsk]] with the formal shaping of the Japanese archipelago.<ref name="Barnes"/> The archipelago also has summits on mountain ridges that were uplifted near the outer edge of the [[continental shelf]].<ref name=loc/> About 73 percent of Japan's area is mountainous, and scattered plains and intermontane basins (in which the population is concentrated) cover only about 27 percent.<ref name=loc/> A long chain of mountains runs down the middle of the archipelago, dividing it into two halves: the "face", facing the Pacific Ocean, and the "back", toward the Sea of Japan.<ref name=loc/> On the Pacific side are steep mountains 1,500 to 3,000 meters high, with deep valleys and gorges.<ref name=loc/>

Central Japan is marked by the convergence of the three mountain chains—the [[Hida Mountains|Hida]], [[Kiso Mountains|Kiso]], and [[Akaishi Mountains|Akaishi mountains]]—that form the [[Japanese Alps]] (''Nihon Arupusu''), several of whose peaks are higher than {{convert|3000|m|ft}}.<ref name=loc/> The highest point in the Japanese Alps is [[Mount Kita]] at {{convert|3193|m|ft}}.<ref name=loc/> The highest point in the country is [[Mount Fuji]] (Fujisan, also erroneously called Fujiyama), a volcano dormant since 1707 that rises to {{convert|3776|m|ft|abbr=on}} above sea level in [[Shizuoka Prefecture]].<ref name=loc/> On the Sea of Japan side are plateaus and low mountain districts, with altitudes of 500 to 1,500 meters.<ref name=loc/>

===Plains===
[[File:Kanto plain.png|thumb|220px|Map of the Kantō Plain]]
There are three major plains in central Honshū. The largest is the [[Kantō Plain]], which covers {{convert|17000|km2|mi2|abbr=on}} in the [[Kantō region]]. The capital Tokyo and the largest metropolitan population are located there.  The second largest plain in Honshū is the [[Nōbi Plain]] ({{convert|1800|km2|mi2|abbr=on}}), with the third-most-populous urban area being [[Nagoya]]. The third-largest plain in Honshū is the [[Osaka Plain]], which covers {{convert|1600|km2|mi2|abbr=on}} in the [[Kinki region]]. It features the second-largest urban area of [[Osaka]] (part of the [[Keihanshin]] metropolitan area). Osaka and Nagoya extend inland from their bays until they reach steep mountains. The Osaka Plain is connected with Kyoto and Nara. [[Kyoto]] is located in the [[Yamashiro Basin]] ({{convert|827.9|km2|mi2|abbr=on}}) and [[Nara, Nara|Nara]] is in the [[Nara Basin]] ({{convert|300|km2|mi2|abbr=on}}).

The Kantō Plain, Osaka Plain, and Nōbi Plain are the most important economic, political, and cultural areas of Japan. These plains had the largest agricultural production and large bays with ports for fishing and trade. This made them the largest population centers. Kyoto and Nara are the ancient capitals and cultural heart of Japan. The Kantō Plain became Japan's center of power because it is the largest plain with a central location, and historically, it had the most agricultural production that could be taxed. The [[Tokugawa Shogunate]] established a ''[[bakufu]]'' in [[Edo (Tokyo)|Edo]] in 1603.<ref>Gordon, Andrew. (2003). ''A Modern History of Japan from Tokugawa Times to the Present'', p. 23.</ref> This evolved into the capital of Tokyo by 1868.

Hokkaido has multiple plains, such as the [[Ishikari Plain]] ({{convert|3800|km2|mi2|abbr=on}}), [[Tokachi Plain]] ({{convert|3600|km2|mi2|abbr=on}}), the [[Kushiro-shitsugen National Park|Kushiro Plain]], the largest wetland in Japan ({{convert|2510|km2|mi2|abbr=on}}), and the [[Sarobetsu Plain]] ({{convert|200|km2|mi2|abbr=on}}). There are many farms that produce a plethora of agricultural products. The average farm size in Hokkaido was 26 hectares per farmer in 2013. That is nearly 11 times larger than the national average of 2.4 hectares. This made Hokkaido the most agriculturally rich prefecture in Japan.<ref name="Agriculture Hokkaido">{{Cite news |title=Trend toward stronger agriculture seen in Hokkaido |url=https://asia.nikkei.com/Business/Biotechnology/Trend-toward-stronger-agriculture-seen-in-Hokkaido/ |work=[[The Nikkei]] |date=5 January 2015 |access-date=7 April 2019 |archive-url=https://web.archive.org/web/20190407200056/https://asia.nikkei.com/Business/Biotechnology/Trend-toward-stronger-agriculture-seen-in-Hokkaido/ |archive-date=7 April 2019 |url-status=live |df=dmy}}</ref> Nearly one-fourth of Japan's arable land and 22% of Japan's forests are in Hokkaido.<ref name="business-env">{{cite web |url=http://www.pref.hokkaido.jp/keizai/kz-bkkry/env/env-e.html |title=Hokkaido's Business Environment |publisher=Trade and Economic Exchange Group, Commerce and Economic Exchange Division, Department of Economic Affairs, Hokkaido Government|access-date=2008-12-05|archive-url=https://web.archive.org/web/20100721020826/http://www.pref.hokkaido.jp/keizai/kz-bkkry/env/env-e.html|archive-date=2010-07-21}}</ref>

Another important plain is the [[Sendai Plain]] around the city of [[Sendai]] in northeastern Honshū.<ref name=loc/> Many of these plains are along the coast, and their areas have been increased by land reclamation throughout recorded history.<ref name=loc/>

===Rivers===
[[File:NiigataCityOpenData machinami004.jpg|thumb|[[Shinano River]] in Niigata City]]
{{main|List of rivers of Japan}}

Rivers are generally steep and swift, and few are suitable for navigation except in their lower reaches. Although most rivers are less than {{convert|300|km|mi|abbr=on}} in length, their rapid flow from the mountains is what provides [[Hydroelectricity in Japan|hydroelectric power]].<ref name=loc/> Seasonal variations in flow have led to the extensive development of flood control measures.<ref name=loc/> The longest, the [[Shinano River]], which winds through [[Nagano Prefecture]] to [[Niigata Prefecture]] and flows into the Sea of Japan, is {{convert|367|km|mi|abbr=on}} long.<ref name=loc/><ref name="longest-rivers"/>

These are the 10 longest rivers of Japan.<ref name="longest-rivers">{{cite web |title=Longest Rivers In Japan |format=website |url=https://www.worldatlas.com/articles/the-longest-rivers-in-japan.html |archive-url=https://web.archive.org/web/20181117105043/https://www.worldatlas.com/articles/the-longest-rivers-in-japan.html |archive-date = November 17, 2018 |publisher=WorldAtlas.com | access-date = 9 February 2020}}</ref>

{| class="wikitable sortable"
! class="unsortable"|Rank
!Name
!Region
!Prefecture
!Length
(km)
|-
|1
|[[Shinano River|Shinano]]
|[[Hokuriku region|Hokuriku]]
|[[Nagano Prefecture|Nagano]], [[Niigata Prefecture|Niigata]]
|367
|-
|2
|[[Tone River|Tone]]
|[[Kantō region|Kantō]]
|[[Saitama Prefecture|Saitama]], [[Chiba Prefecture|Chiba]], [[Ibaraki Prefecture|Ibaraki]], [[Tochigi Prefecture|Tochigi]], [[Gunma Prefecture|Gunma]]
|322
|-
|3
|[[Ishikari River|Ishikari]]
|[[Hokkaido]]
|[[Hokkaido]]
|268
|-
|4
|[[Teshio River|Teshio]]
|[[Hokkaido]]
|[[Hokkaido]]
|256
|-
|5
|[[Kitakami River|Kitakami]]
|[[Tōhoku Region|Tōhoku]]
|[[Iwate Prefecture|Iwate]], [[Miyagi Prefecture|Miyagi]]
|249
|-
|6
|[[Abukuma River|Abukuma]]
|[[Tōhoku region|Tōhoku]]
|[[Fukushima Prefecture|Fukushima]], [[Miyagi Prefecture|Miyagi]]
|239
|-
|7
|[[Mogami River|Mogami]]
|[[Tōhoku region|Tōhoku]]
|[[Yamagata Prefecture|Yamagata]]
|229
|-
|8
|[[Tenryū River|Tenryu]]
|[[Chūbu region|Chūbu]]
|[[Nagano Prefecture|Nagano]], [[Aichi Prefecture|Aichi]], [[Shizuoka Prefecture|Shizuoka]]
|212
|-
|9
|[[Agano River|Agano]]
|[[Hokuriku region|Hokuriku]]
|[[Niigata Prefecture|Niigata]]
|210
|-
|10
|[[Shimanto River|Shimanto]]
|[[Shikoku]]
|[[Kōchi Prefecture|Kōchi]]
|196
|}

===Lakes and coasts===
[[File:20091015琵琶湖.jpg|thumb|Aerial view of [[Lake Biwa]]]]
{{main|List of lakes of Japan}}

The largest freshwater lake is [[Lake Biwa]] ({{convert|670.3|km2|sqmi|abbr=on}}), northeast of Kyoto in [[Shiga Prefecture]].<ref name=Tabata2016>{{Cite journal |doi=10.1002/ece3.2070 |title=Phylogeny and historical demography of endemic fishes in Lake Biwa: The ancient lake as a promoter of evolution and diversification of freshwater fishes in western Japan |year=2016 |last1=Tabata |first1=Ryoichi |last2=Kakioka |first2=Ryo |last3=Tominaga |first3=Koji |last4=Komiya |first4=Takefumi |last5=Watanabe |first5=Katsutoshi |journal=Ecology and Evolution |volume=6 |issue=8 |pages=2601–2623 |pmid=27066244 |pmc=4798153|bibcode=2016EcoEv...6.2601T }}</ref> Lake Biwa is an [[ancient lake]] and is estimated to be the 13th oldest lake in the world, dating to at least 4 million years ago.<ref name="marine-rutgers">{{cite web |title=Ancient lakes of the world |url=https://marine.rutgers.edu/~cfree/ancient-lakes-of-the-world/|archive-url=https://web.archive.org/web/20200209063201/https://marine.rutgers.edu/~cfree/ancient-lakes-of-the-world/|archive-date=February 9, 2020|access-date=20 January 2020 |publisher=Christopher M. Free |format=website}}</ref><ref name=Tabata2016/> It has consistently carried water for millions of years. Lake Biwa was created by plate tectonics in an active rift zone. This created a very deep lake with a maximum depth of {{convert|104|m|feet|abbr=on}}. Thus, it is not naturally filled with sediment. Over the course of millions of years, a diverse ecosystem evolved in the lake. It has more than 1,000 species and subspecies. There are 46 native fish species and subspecies,<ref name=fish>Kawanabe, H.; Nishino, M.; and Maehata, M., editors (2012). ''Lake Biwa: Interactions between Nature and People.'' pp 119-120. {{ISBN|978-94-007-1783-1}}</ref> including 11 species and 5 subspecies that are endemic or near-endemic.<ref name=Tabata2016/> Approximately 5,000 [[Anatidae|water birds]] visit the lake each year.

The following are the 10 largest lakes of Japan.<ref name="GSI-20172">[[国土地理院]] 平成29年全国都道府県市区町村別面積調 [http://www.gsi.go.jp/KOKUJYOHO/MENCHO/201710/f1_kosho.pdf 付1 湖沼面積（平成29年10月1日版）] {{Webarchive|url=https://web.archive.org/web/20180210003158/http://www.gsi.go.jp/KOKUJYOHO/MENCHO/201710/f1_kosho.pdf|date=2018-02-10}} 2018年2月10日閲覧。</ref>

{| class="wikitable sortable"
|-
! class="unsortable"|Rank
! Name
! Region
! Prefecture
! class="unsortable"|Municipalities
!Type
! class="unsortable"|Water [[salinity]]
! Area (km<sup>2</sup>)
! Max Depth (m)
! Altitude (m)
! Volume (km<sup>3</sup>)
|-
| 1 || [[Lake Biwa|Biwa]] || [[Kansai region|Kansai]] || [[Shiga Prefecture|Shiga]] || [[Ōtsu, Shiga|Ōtsu]], [[Kusatsu, Shiga|Kusatsu]], [[Higashiōmi, Shiga|Higashi-Ōmi]], [[Hikone, Shiga|Hikone]]<br />[[Nagahama, Shiga|Nagahama]], [[Moriyama, Shiga|Moriyama]], [[Ōmihachiman, Shiga|Ōmi-Hachiman]]<br />[[Takashima, Shiga|Takashima]], [[Yasu, Shiga|Yasu]], [[Maibara, Shiga|Maibara]]
|[[Ancient lake]], [[Lake|tectonic]], [[freshwater]]|| Fresh || 670.3 || 103.8 || 85|| 27.5
|-
| 2 || [[Lake Kasumigaura|Kasumigaura]] || [[Kantō region|Kantō]] || [[Ibaraki Prefecture|Ibaraki]] || [[Tsuchiura, Ibaraki|Tsuchiura]], [[Ishioka, Ibaraki|Ishioka]], [[Omitama, Ibaraki|Omitama]], [[Inashiki, Ibaraki|Inashiki]]<br />[[Ami, Ibaraki|Ami]], [[Kasumigaura, Ibaraki|Kasumigaura]], [[Namegata, Ibaraki|Namegata]], [[Itako, Ibaraki|Itako]], [[Miho, Ibaraki|Miho]]
|Warm [[monomictic lake]]|| Fresh || 167.6 || 7.10 || 0 || 0.85
|-
| 3 || [[Lake Saroma|Saroma]] || [[Hokkaido]] || [[Okhotsk Subprefecture|Okhotsk]] || [[Kitami]], [[Saroma, Hokkaido|Saroma]], [[Yūbetsu, Hokkaido|Yūbetsu]]
|[[Mesotrophic lake|Mesotrophic]]|| Brackish || 151.9 || 19.6 || 0 || 1.3
|-
| 4 || [[Lake Inawashiro|Inawashiro]] || [[Tōhoku region|Tōhoku]] || [[Fukushima Prefecture|Fukushima]] || [[Kōriyama, Fukushima|Kōriyama]], [[Aizuwakamatsu, Fukushima|Aizu-Wakamatsu]], [[Inawashiro, Fukushima|Inawashiro]]
|[[Tectonics|Tectonic]] lake|| Fresh || 103.3 || 94.6 || 514 || 5.40
|-
| 5 || [[Nakaumi]] || [[San'in region|San'in]] || [[Shimane Prefecture|Shimane]]<br />[[Tottori Prefecture|Tottori]] || [[Matsue, Shimane|Matsue]], [[Yonago, Tottori|Yonago]], [[Yasugi, Shimane|Yasugi]], [[Sakaiminato, Tottori|Sakaiminato]]
|[[Brackish]]|| Brackish || 86.2 || 17.1 || 0 || 0.47
|-
| 6 || [[Lake Kussharo|Kussharo]] || [[Hokkaido]] || [[Kushiro Subprefecture|Kushiro]] || [[Teshikaga, Hokkaido|Teshikaga]]
|Acidotrophic [[Volcanic crater lake|crater lake]]|| Fresh || 79.3 || 117.5 || 121 || 2.25
|-
| 7 || [[Lake Shinji|Shinji]] || [[San'in region|San'in]] || [[Shimane Prefecture|Shimane]] || [[Matsue, Shimane|Matsue]], [[Izumo, Shimane|Izumo]]
|[[Brackish water|Brackish]]|| Brackish || 79.1 || 6.0 || 0 || 0.34
|-
| 8 || [[Lake Shikotsu|Shikotsu]] || [[Hokkaido]] || [[Ishikari Subprefecture|Ishikari]] || [[Chitose, Hokkaido|Chitose]]
|[[Volcanic crater lake|Crater lake]]|| Fresh || 78.4 || 360.1 || 247 || 20.9
|-
| 9 || [[Lake Tōya|Tōya]] || [[Hokkaido]] || [[Iburi Subprefecture|Iburi]] || [[Tōyako, Hokkaido|Tōyako]], [[Sōbetsu, Hokkaido|Sōbetsu]]
|[[Oligotroph]]ic [[Volcanic crater lake|crater lake]]|| Fresh || 70.7 || 179.9 || 84 || 8.19
|-
| 10 || [[Lake Hamana|Hamana]] || [[Tōkai region|Tōkai]] || [[Shizuoka Prefecture|Shizuoka]] || [[Hamamatsu, Shizuoka|Hamamatsu]], [[Kosai, Shizuoka|Kosai]]
|[[Brackish water|Brackish]] [[lagoon]]|| Brackish || 65.0 || 13.1 || 0 || 0.35
|}

[[File:Seto_Inland_Sea.jpg|thumb|[[Seto Inland Sea]]]]
Extensive coastal shipping, especially around the Seto Inland Sea, compensates for the lack of navigable rivers.<ref name=loc/> The Pacific coastline south of Tokyo is characterized by long, narrow, gradually shallowing inlets produced by sedimentation, which has created many natural harbors.<ref name=loc/> The Pacific coastline north of Tokyo, the coast of Hokkaido, and the Sea of Japan coast are generally unindented, with few natural harbors.<ref name=loc/>

A recent global remote sensing analysis suggested that there were 765&nbsp;km<sup>2</sup> of tidal flats in Japan, making it the 35th-ranked country in terms of tidal flat extent.<ref>{{cite journal |last1=Murray |first1=N.J. |last2=Phinn |first2=S.R. |last3=DeWitt |first3=M. |last4=Ferrari |first4=R. |last5=Johnston |first5=R. |last6=Lyons |first6=M.B. |last7=Clinton |first7=N. |last8=Thau |first8=D. |last9=Fuller |first9=R.A. |title=The global distribution and trajectory of tidal flats |journal=Nature |date=2019 |volume=565 |issue=7738 |pages=222–225 |doi=10.1038/s41586-018-0805-8 |pmid=30568300 |s2cid=56481043 |url=https://www.nature.com/articles/s41586-018-0805-8 |access-date=2021-08-03 |archive-date=2021-11-24 |archive-url=https://web.archive.org/web/20211124213205/https://www.nature.com/articles/s41586-018-0805-8 |url-status=live }}</ref>

===Land reclamation===
[[File:151229_Kobe_Port_Japan02bs.jpg|thumb|[[Kobe Airport]] in [[Osaka Bay]]]]
The Japanese archipelago has been transformed by humans into a sort of continuous land, in which the four main islands are entirely reachable and passable by rail and road transportation thanks to the construction of huge bridges and tunnels that connect each other and various islands.<ref>{{cite book |title=Il mondo come sistema |author=E. Fedrizzi and S. Ferri |year=2000 |publisher=Minerva Italica |isbn=88-298-1989-1}}</ref>

Approximately 0.5% of Japan's total area is reclaimed land (''umetatechi'').<ref name="reclaimed-land"/> It began in the 12th century.<ref name="reclaimed-land"/> Land was reclaimed from the sea and from river deltas by building [[Levee|dikes]], drainage, and rice paddies on terraces carved into mountainsides.<ref name=loc/> The majority of [[land reclamation]] projects occurred after World War II, during the [[Japanese economic miracle]]. Reclamation of 80% to 90% of all the tidal flatland was done. Large land reclamation projects with [[landfill]]s were done in coastal areas for maritime and industrial factories, such as [[Higashi Ogishima]] in [[Kawasaki, Kanagawa|Kawasaki]], [[Osaka Bay]], and [[Nagasaki Airport]]. [[Port Island]], [[Rokkō Island]], and [[Kobe Airport]] were built in [[Kobe]]. Late 20th and early 21st century projects include [[artificial islands]] such as [[Chubu Centrair International Airport]] in [[Ise Bay]], [[Kansai International Airport]] in the middle of Osaka Bay, [[Yokohama Hakkeijima Sea Paradise]], and [[Wakayama Marina City]].<ref name="reclaimed-land">{{cite web |url=http://japanpropertycentral.com/real-estate-faq/reclaimed-land-in-japan/ |title=Reclaimed Land in Japan |date=13 November 2011 |publisher=Japan Property Central |access-date=2018-09-26 |url-status=live |archive-url=https://web.archive.org/web/20180226211747/http://japanpropertycentral.com/real-estate-faq/reclaimed-land-in-japan/ |archive-date=2018-02-26}}</ref> The village of [[Ōgata, Akita|Ōgata]] in [[Akita, Japan|Akita]] was established on land reclaimed from [[Hachirōgata|Lake Hachirōgata]] (Japan's second largest lake at the time) starting in 1957. By 1977, the amount of land reclaimed totaled {{convert|172.03|km2}}.<ref>{{cite web |url=http://www.ogata.or.jp/english/history.html |title=The History of Ogata-Mura {{pipe}} Ogata-mura |publisher=Ogata.or.jp |access-date=2014-04-17 |url-status=dead |archive-url=https://web.archive.org/web/20150924055244/http://www.ogata.or.jp/english/history.html |archive-date=2015-09-24}}</ref>

Examples of land reclamation in Japan include:
* Kyogashima, [[Kobe]] – the first human-made island built by [[Taira no Kiyomori]] in 1173<ref name="reclaimed-land"/>
* The [[Hibiya]] Inlet, Tokyo – the first large-scale reclamation project started in 1592<ref name="reclaimed-land"/>
* [[Dejima]], Nagasaki –  built during Japan's national isolation period in 1634. It was the sole trading post in Japan during the Sakoku period and was originally inhabited by Portuguese and then Dutch traders.<ref name="reclaimed-land"/>
* [[Tokyo Bay]], Japan – {{convert|249|km2}}<ref>{{cite web |title=Japan Fact Sheet |publisher=Japan Reference |url=http://www.jref.com/society/japan_fact_sheet.shtml |access-date=2007-03-23 |archive-date=2007-02-27 |archive-url=https://web.archive.org/web/20070227234242/http://www.jref.com/society/japan_fact_sheet.shtml |url-status=live }}</ref> [[artificial island]] (2007)
** This includes the entirety of [[Odaiba]], a series of island forts constructed to protect Tokyo from sea attacks (1853).<ref name="reclaimed-land"/>
* [[Kobe]], Japan – {{convert|23|km2}} (1995).<ref name="reclaimed-land"/>
* Isahaya Bay in the [[Ariake Sea]] – approximately {{convert|35|km2}} is reclaimed with tide embankment and sluice gates (2018).
* [[Yumeshima]], Osaka – {{convert|390|ha}} artificial island (2025)
* [[Central Breakwater]] – {{convert|989|ha}}
Much reclaimed land is made up of landfill waste materials, dredged earth, sand, sediment, sludge, and soil removed from construction sites. It is used to build human-made islands in harbors and embankments in inland areas.<ref name="reclaimed-land"/> On November 8, 2011, [[Tokyo City]] began accepting rubble and waste from the [[2011 Tōhoku earthquake and tsunami]] region. This rubble was processed, and when it had the appropriate radiation levels, it was used as a landfill to build new artificial islands in Tokyo Bay. [[Yamashita Park]] in [[Yokohama City]] was made with rubble from the [[great Kantō earthquake]] in 1923.<ref name="reclaimed-land"/>

There is a risk of contamination on artificial islands with landfills and reclaimed land if there was industry that spilled toxic chemicals into the ground. For example, the artificial island of [[Toyosu]] was once occupied by a Tokyo gas factory. Toxic substances were discovered in the soil and groundwater at Toyosu. The [[Tokyo Metropolitan Government]] spent an additional 3.8 billion yen ($33.5 million) to pump out groundwater by digging hundreds of wells.<ref name="historic-tsukiji">{{cite news |url=https://widerimage.reuters.com/story/as-historic-tsukiji-market-closes-fishmongers-mourn |access-date=October 4, 2018 |title=As Tokyo's historic Tsukiji market closes, fishmongers mourn |first=Issei |last=Kato |date=29 September 2018 |work=Reuters  |url-status=live |archive-url=https://web.archive.org/web/20181003005402/https://widerimage.reuters.com/story/as-historic-tsukiji-market-closes-fishmongers-mourn |archive-date=October 3, 2018}}</ref> In June 2017, plans to move the [[Tsukiji fish market]] were restarted<ref>{{cite news |last1=Osumi |first1=Magdalena |last2=Aoki |first2=Mizuho |title=Koike announces Tsukiji relocation, plans to retain its 'cultural legacy' |url=http://www.japantimes.co.jp/news/2017/06/20/national/tokyo-governor-announces-tsukiji-fish-markets-relocation-possible-plan-return-five-years/ |access-date=24 July 2017 |work=[[Japan Times]] |date=20 June 2017 |archive-date=13 August 2023 |archive-url=https://web.archive.org/web/20230813185501/https://www.japantimes.co.jp/news/2017/06/20/national/tokyo-governor-announces-tsukiji-fish-markets-relocation-possible-plan-return-five-years/ |url-status=live }}</ref> but delayed from July to the autumn of 2018.<ref>{{cite news |title=Tsukiji market relocation to Toyosu delayed till autumn 2018 |url=https://mainichi.jp/english/articles/20170721/p2a/00m/0na/016000c |access-date=24 July 2017 |work=[[Mainichi Shimbun|The Mainichi]] |date=21 July 2017 |archive-date=12 August 2023 |archive-url=https://web.archive.org/web/20230812142028/https://mainichi.jp/english/articles/20170721/p2a/00m/0na/016000c |url-status=live }}</ref> After the new site was declared safe following a cleanup operation, [[Toyosu Market]] was opened.<ref>{{cite news |url=https://www.theguardian.com/world/2018/aug/26/tokyo-tsukiji-fish-market-moves |title=Tokyo fears losing a part of its soul as world's biggest fish market moves |first=Justin |last=McCurry |date=26 August 2018 |work=The Guardian |access-date=17 October 2018 |archive-date=12 August 2023 |archive-url=https://web.archive.org/web/20230812140613/https://www.theguardian.com/world/2018/aug/26/tokyo-tsukiji-fish-market-moves |url-status=live }}</ref>