The Sea of Japan is the marginal sea between the Japanese archipelago, Sakhalin, the Korean Peninsula, and the mainland of the Russian Far East. The Japanese archipelago separates the sea from the Pacific Ocean. Like the Mediterranean Sea, it has almost no tides due to its nearly complete enclosure from the Pacific Ocean. This isolation also affects faunal diversity and salinity, both of which are lower than in the open ocean. The sea has no large islands, bays or capes. Its water balance is mostly determined by the inflow and outflow through the straits connecting it to the neighboring seas and the Pacific Ocean. Few rivers discharge into the sea and their total contribution to the water exchange is within 1%.
The seawater has an elevated concentration of dissolved oxygen that results in high biological productivity. Therefore, fishing is the dominant economic activity in the region. The intensity of shipments across the sea has been moderate owing to political issues, but it is steadily increasing as a result of the growth of East Asian economies.
Names Sea of Japan is the dominant term used in English for the sea. The sea is called (, ) in Japan, (, ) or originally (, ) in China,2006. "鲸海"这个名字如何改成了"日本海" . Retrieved on 7 March 2017 (, ) in Russia, (, ) in North Korea, and (, ) in South Korea.
Naming dispute
The naming of the sea is the subject of an ongoing dispute between Japan, North Korea, and South Korea. Japan uses the name Sea of Japan and asserts that it has been the internationally accepted term since the early 19th century.The Issue of Name "Sea of Japan", The Ministry of Foreign Affairs of Japan In contrast, South Korea contends that the East Sea was historically used before Japanese colonial rule,East Sea, Korea.netEast Sea, Ministry of Foreign Affairs of Korea and officially requests that it be used alongside Sea of Japan. North Korea advocates for the name East Sea of Korea.Efforts of the Government of Japan in Response to the Issue of the Name of the Sea of Japan (1) The 8th UNCSGN, The Ministry of Foreign Affairs of Japan
Limits of Oceans and Seas (S-23), published by the International Hydrographic Organization (IHO), had been using the name Japan Sea since it was first published in 1928. It has not been updated since 1953 and is not able to effectively serve as an international standard in today's digital environment. In 2020, the IHO decided to develop a new digital standard, S-130, to meet modern Geographic Information System (GIS) requirements and replace the geographic names in S-23 with unique identifiers for each maritime area in S-130.Decisions of the 2nd Session of the IHO Assembly, International Hydrographic Organization."IHO reaches agreement on identifying seas with numbers amid East Sea naming row", Yonhap News Agency on 17 November 2020. The IHO Secretary-General stated that S-23, the previous version of the nautical chart made in 1953 will be kept publicly available simply to demonstrate the evolutionary process from the analogue to the digital era.Report on the informal consultation process for the future of S-23, International Hydrographic Organization. S-130 was formally adopted at the fourth session of the IHO Assembly, held in Monaco from 19 to 23 April 2026. According to the IHO, the standard provides unique numerical identifiers for oceans and seas instead of names, and enables countries to use their name of choice in their own national products and services, and it is expected that IHO charts will no longer bear traditional names like Japan Sea. The South Korean Ministry of Foreign Affairs stated that the adoption reflected the country's efforts to challenge the exclusive use of the name Sea of Japan.
History For centuries, the sea had protected Japan from land invasions, particularly by the Mongols. It had long been navigated by Asian and, from the 18th century, by European ships. Russian expeditions of 1733–1743 mapped Sakhalin and the Japanese islands. In the 1780s, the Frenchman Jean-François de Galaup, comte de Lapérouse, traveled northward across the sea through the strait later named after him. In 1796, a British naval officer, William Robert Broughton, explored the Strait of Tartary, the eastern coast of the Russian Far East and the Korean Peninsula.
In 1803–1806, the Russian navigator Adam Johann von Krusenstern while sailing across the globe in the ship Nadezhda also explored, in passing, the Sea of Japan and the eastern shores of Japanese islands. In 1849, another Russian explorer Gennady Nevelskoy discovered the strait between the continent and Sakhalin and mapped the northern part of the Strait of Tartary. Russian expeditions were made in 1853–1854 and 1886–1889 to measure the surface temperatures and record the tides. They also documented the cyclonal character of the sea currents.
Other notable expeditions of the 19th century include the American North Pacific Exploring and Surveying Expedition (1853–1856) and British Challenger expedition (1872–1876). The aquatic life was described by V. K. Brazhnikov in 1899–1902 and P. Yu. Schmidt in 1903–1904. The Japanese scientific studies of the sea began only in 1915 and became systematic since the 1920s.
American, Canadian and French whaleships cruised for whales in the sea between 1847 and 1892.Athol, of St. John, 8 June – 10 August 1847, NBW 1335; Vesper, of New London, 20 April – 26 August 1848, G. W. Blunt White Library (GBWL); Northern Light, of New Bedford, 14 May – 22 July 1875, Old Dartmouth Historical Society (ODHS); Cape Horn Pigeon, of New Bedford, 17 April – 13 July 1892, Kendall Whaling Museum (KWM). Most entered the sea via Korea StraitSplendid, of Edgartown, 17 April 1848, Nicholson Whaling Collection (NWC); Fortune, of New Bedford, 12 March 1849, ODHS; Sea Breeze, of New Bedford, 14 April 1874, GWBL. and left via La Pérouse Strait,Bowditch, of Warren, 2 August 1848, NWC; Arnolda, of New Bedford, 17 June 1874, ODHS. but some entered and exited via Tsugaru Strait.Good Return, of New Bedford, 30 April 1849, ODHS; Milo, of New Bedford, 16–18 Apr. 1850, ODHS. They primarily targeted right whales,Eliza Adams, of Fairhaven, 21 April – 4 August 1848, ODHS; Huntress, of New Bedford, 4 May – 3 July 1848, NWC. but began catching humpbacks as right whale catches declined.Florida, of Fairhaven, 12–27 May 1860, in One Whaling Family (Williams, 1964); Sea Breeze, of New Bedford, 11–12 May, 4–5 June 1874, GWBL. They also made attempts to catch blueGeorge Washington, of Wareham, 16 May 1849, ODHS; Florida, of Fairhaven, 5 May 1860, in One Whaling Family (Williams, 1964). and fin whales,Daniel Wood, of New Bedford, 6 April 1854, NWC. but these species invariably sank after being killed. Right whales were caught from March to September,Henry Kneeland, of New Bedford, 1 September 1852, in Enoch's Voyage (1994), pp. 153–154. with peak catches in May and June.Catch of right whales by month based on over 510 whales caught during 71 vessel seasons from 1847 to 1891: June (31.7%), May (28.8%), July (19.9%), April (11.8%), and August (5.4%). During the peak years of 1848 and 1849 a total of over 170 vessels (over 60 in 1848, and over 110 in 1849) cruised in the Sea of Japan,Ships spoken in 1848 by Vesper (GBWL); Eliza Adams (ODHS); Splendid (NWC); Bowditch (NWC); Huntress (NWC); Liverpool 2nd, of New Bedford (NWC); Cherokee, of New Bedford (NWC); and Mechanic, of Newport (NWC); Hannibal, of Sag Harbor (EHL); Josephine, of Sag Harbor (EHL); John Jay, of Sag Harbor (NHA); in 1849 by Huntress (NWC); Good Return (ODHS); Fortune (ODHS); Ocmulgee, of Holmes Hole (ODHS); Mary and Susan (NWC); Maria Theresa, of New Bedford (ODHS); George Washington (ODHS); Liverpool 2nd (NWC); Julian, of New Bedford (NWC); Henry Kneeland, of New Bedford (ODHS), Montpelier, of New Bedford (NWC), Cambria, of New Bedford (NWC), India, of New Bedford (ODHS), and Phoenix, of New Bedford (NHA); N. P. Tallmadge, Pioneer, and Superior, of New London (GBWL), Alpha, of Nantucket (NHA), and Prudent, of Stonington (GBWL). with significantly lesser numbers in following years.Ships spoken in 1856 by Pacific, of Fairhaven (NWC), and Onward, of New Bedford (NWC); and from 1859 to 1861 by Florida, of Fairhaven, in One Whaling Family (Williams, 1964).
Geography and geology
The Sea of Japan was landlocked when the land bridge of East Asia existed. The Japan Arc started to form in the Early Miocene. In the Early Miocene the Japan Sea started to open, and the northern and southern parts of the Japanese archipelago separated from each other. During the Miocene, the Sea of Japan expanded.
The north part of the Japanese archipelago was further fragmented later until orogenesis of the north-eastern Japanese archipelago began in the later Late Miocene. The south part of the Japanese archipelago remained as a relatively large landmass. The land area had expanded northward in the Late Miocene. The orogenesis of high mountain ranges in north-eastern Japan started in Late Miocene and lasted in Pliocene also. The eastern margin of the sea may host an incipient subduction zone responsible for large earthquakes in 1940, 1964, 1983 and 1993.
Nowadays the Sea of Japan is bounded by the Russian mainland and Sakhalin island to the north, the Korean Peninsula to the west, and the Japanese islands of Hokkaidō, Honshū and Kyūshū to the east and south. It is connected to other seas by five straits: the Strait of Tartary between the Asian mainland and Sakhalin; La Pérouse Strait between Sakhalin and Hokkaidō; the Tsugaru Strait between Hokkaidō and Honshū; the Kanmon Straits between Honshū and Kyūshū; and the Korea Strait between the Korean Peninsula and Kyūshū.
The Korea Strait is composed of the Western Channel and the Tsushima Strait, on either side of Tsushima Island. The straits were formed in recent geologic periods. The oldest of them are the Tsugaru and Tsushima straits. Their formation had interrupted the migration of elephants into the Japanese islands at the end of the Neogene Period (about 2.6 million years ago). The most recent is La Perouse Strait, which formed about 60,000 to 11,000 years ago closing the path used by mammoths which had earlier moved to northern Hokkaidō. All the straits are rather shallow, with a minimal depth of the order of 100 meters or less. This hinders water exchange, thereby isolating the water and aquatic life of the Sea of Japan from the neighboring seas and oceans.
The sea has a surface area of about , a mean depth of and a maximum depth of . It has a carrot-like shape, with the major axis extending from south-west to north-east and a wide southern part narrowing toward the north. The coastal length is about with the largest part () belonging to Russia. The sea extends from north to south for more than and has a maximum width of about .Sea of Japan, Great Soviet Encyclopedia (in Russian)
It has three major basins: the Yamato Basin in the south-east, the Japan Basin in the north and the Tsushima Basin (Ulleung Basin) in the south-west.Sea of Japan, Encyclopædia Britannica on-line The Japan Basin is of oceanic origin and is the deepest part of the sea, whereas the Tsushima Basin is the shallowest with the depths below . On the eastern shores, the continental shelves of the sea are wide, but on the western shores, particularly along the Korean coast, they are narrow, averaging about .
There are three distinct continental shelves in the northern part (above 44° N). They form a staircase-like structure with the steps slightly inclined southwards and submerged to the depths of , and . The last step sharply drops to the depths of about toward the central (deepest) part of the sea. The bottom of this part is relatively flat, but has a few plateaus. In addition, an underwater ridge rising up to runs from north to south through the middle of the central part.