Sea of Japan in the context of "North Korea"

Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asian mainland, it is bordered to the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea in the south. The Japanese archipelago consists of four major islands alongside 14,121 smaller islands. Japan is divided into 47 administrative prefectures and eight traditional regions, and around 75% of its terrain is mountainous and heavily forested, concentrating its agriculture and highly urbanized population along its eastern coastal plains. With a population of over 123 million as of 2025, it is the world's 11th most populous country. Tokyo is the country's capital and largest city.

The first known habitation of the archipelago dates to the Upper Paleolithic, with the beginning of the Japanese Paleolithic dating to c. 36,000 BC. Between the 4th and 6th centuries, its kingdoms were united under an emperor in Nara and later Heian-kyō. From the 12th century, actual power was held by military aristocrats known as shōgun and feudal lords called daimyō, enforced by warrior nobility named samurai. After rule by the Kamakura and Ashikaga shogunates and a century of warring states, Japan was unified in 1600 by the Tokugawa shogunate, which implemented an isolationist foreign policy. In 1853, an American fleet forced Japan to open trade to the West, which led to the end of the shogunate and the restoration of imperial power in 1868.

Honshu (Japanese: 本州, Hepburn: Honshū; pronounced [hoꜜɰ̃.ɕɯː] ; lit. 'main province'), historically known as Akitsushima (秋津島; lit. 'dragonfly island'), is the largest of Japan's four main islands. It lies between the Pacific Ocean (east) and the Sea of Japan (west). It is the seventh-largest island in the world, and the second-most populous after the Indonesian island of Java.

Honshu had a population of 104 million as of 2017, constituting 81.3% of the entire population of Japan, and mostly concentrated in the coastal areas and plains. Approximately 30% of the total population resides in the Greater Tokyo Area on the Kantō Plain. As the historical center of Japanese cultural and political power, the island includes several past Japanese capitals, including Kyoto, Nara, and Kamakura. Much of the island's southern shore forms part of the Taiheiyō Belt, a megalopolis that spans several of the Japanese islands. Honshu also contains Japan's highest mountain, Mount Fuji, and its largest lake, Lake Biwa.

The Mongol Empire was the largest contiguous empire in history. Originating in present-day Mongolia in East Asia, the empire at its height stretched from the Sea of Japan to Eastern Europe, extending northward into Siberia and east and southward into the Indian subcontinent, mounting invasions of Southeast Asia, and conquering the Iranian plateau; and reaching westward as far as the Levant and the Carpathian Mountains.

The empire emerged from the unification of several nomadic tribes in the Mongol heartland under the leadership of Temüjin, known by the title of Genghis Khan (c. 1162–1227), whom a council proclaimed as the ruler of all Mongols in 1206. The empire grew rapidly under his rule and that of his descendants, who sent out invading armies in every direction. The vast transcontinental empire connected the East with the West, and the Pacific to the Mediterranean, in an enforced Pax Mongolica, allowing the exchange of trade, technologies, commodities, and ideologies across Eurasia.

The Chūbu region (中部地方, Chūbu-chihō), Central region, or Central Japan (中部日本, Chūbu-nihon) is a large and diverse region in the middle of Honshū, Japan's main island. In a wide, classical definition, it encompasses nine prefectures (ken): Aichi, Fukui, Gifu, Ishikawa, Nagano, Niigata, Shizuoka, Toyama, and Yamanashi.

It is located directly between the Kantō region and the Kansai region and includes the major city of Nagoya as well as Pacific Ocean and Sea of Japan coastlines, extensive mountain resorts, and Mount Fuji.

Kyoto Prefecture (京都府, Kyōto-fu; Japanese pronunciation: [kʲoꜜː.to, kʲoː.toꜜ.ɸɯ]) is a prefecture of Japan located in the Kansai region of Honshu. Kyoto Prefecture has a population of 2.58 million and has a geographic area of 4,612 square kilometres (1,781 sq mi). Kyoto Prefecture borders Fukui Prefecture to the northeast, Shiga Prefecture to the east, Mie Prefecture to the southeast, Nara Prefecture and Osaka Prefecture to the south, and Hyōgo Prefecture to the west.

Kyoto, the capital and largest city, accommodates 57% of the prefecture's total population, with other major cities including Uji, Kameoka, and Maizuru. Kyoto Prefecture is located on the Sea of Japan coast and extends to the southeast towards the Kii Peninsula, covering territory of the former provinces of Yamashiro, Tamba, and Tango. Kyoto Prefecture is centered on the historic Imperial capital of Kyoto, and is one of Japan's two "prefectures" using the designation fu rather than the standard ken for prefectures. Kyoto has made Kyoto Prefecture one of the most popular tourism destinations in Japan for national and international tourists, and 21% of the prefecture's land area was designated as Natural Parks. Kyoto Prefecture forms part of the Keihanshin metropolitan area, the second-most-populated region in Japan after the Greater Tokyo area and one of the world's most productive regions by GDP.

South Korea, officially the Republic of Korea (ROK), is a country in East Asia. It constitutes the southern half of the Korean Peninsula and borders North Korea along the Korean Demilitarized Zone, with the Yellow Sea to the west and the Sea of Japan to the east. Like North Korea, South Korea claims to be the sole legitimate government of the entire peninsula and adjacent islands. It has a population of about 52 million, of which half live in the Seoul metropolitan area, the ninth most populous metropolitan area in the world; other major cities include Busan, Daegu, and Incheon.

The Korean Peninsula was inhabited as early as the Lower Paleolithic period. Its first kingdom was noted in Chinese records in the early seventh century BC. From the mid first century BC, various polities consolidated into the rival kingdoms of Goguryeo, Baekje, and Silla. The lattermost eventually unified most of the peninsula for the first time in the late seventh century AD, while Balhae succeeded Goguryeo in the north. The Goryeo dynasty (918–1392) achieved lasting unification and established the basis for the modern Korean identity. The subsequent Joseon dynasty (1392–1897) generated cultural, economic, and scientific achievements and also established isolationism starting from the mid-17th century. The succeeding Korean Empire (1897–1910) sought modernization and reform but was annexed in 1910 into the Empire of Japan. Japanese rule ended following Japan's surrender in World War II, after which Korea was divided into two zones: the Soviet-occupied northern zone and the United States-occupied southern zone. After negotiations on reunification failed, the southern zone became the Republic of Korea in August 1948, while the northern zone became the communist Democratic People's Republic of Korea the following month.

Sakhalin (Russian: Сахалин, IPA: [səxɐˈlʲin]) is an island in Northeast Asia. Its north coast lies 6.5 km (4.0 mi) off the southeastern coast of Khabarovsk Krai in Russia, while its southern tip lies 40 kilometres (25 mi) north of the Japanese island of Hokkaido. An island of the West Pacific, Sakhalin divides the Sea of Okhotsk to its east from the Sea of Japan to its southwest. It is administered as part of Sakhalin Oblast and is the largest island of Russia, with an area of 72,492 square kilometres (27,989 sq mi). The island has a population of roughly 500,000, the majority of whom are Russians. The indigenous peoples of the island are the Ainu, Oroks, and Nivkhs, who are now present in very small numbers.

The island's name is derived from the Manchu word Sahaliyan (ᠰᠠᡥᠠᠯᡳᠶᠠᠨ), which was the name of the Qing dynasty city of Aigun. The Ainu people of Sakhalin paid tribute to the Yuan, Ming, and Qing dynasties and accepted official appointments from them. Sometimes the relationship was forced but control from dynasties in China was loose for the most part.

The Qing dynasty (/tʃɪŋ/ CHING), officially the Great Qing, was a Manchu-led imperial dynasty of China and an early modern empire in East Asia. The last imperial dynasty in Chinese history, the Qing dynasty was preceded by the Ming dynasty and succeeded by the Republic of China. At its height of power, the empire stretched from the Sea of Japan in the east to the Pamir Mountains in the west, and from the Mongolian Plateau in the north to the South China Sea in the south. Originally emerging from the Later Jin dynasty founded in 1616 and proclaimed in Shenyang in 1636, the dynasty seized control of the Ming capital Beijing and North China in 1644, traditionally considered the start of the dynasty's rule. The dynasty lasted until the Xinhai Revolution of October 1911 led to the abdication of the last emperor in February 1912. The multi-ethnic Qing dynasty assembled the territorial base for modern China. The Qing controlled the most territory of any dynasty in Chinese history, and in 1790 represented the fourth-largest empire in world history to that point. With over 426 million citizens in 1907, it was the most populous country at the time.

Nurhaci, leader of the Jianzhou Jurchens and House of Aisin-Gioro who was also a vassal of the Ming dynasty, unified Jurchen clans (known later as Manchus) and founded the Later Jin dynasty in 1616, renouncing the Ming overlordship. As the founding Khan of the Manchu state he established the Eight Banners military system, and his son Hong Taiji was declared Emperor of the Great Qing in 1636. As Ming control disintegrated, peasant rebels captured Beijing as the short-lived Shun dynasty, but the Ming general Wu Sangui opened the Shanhai Pass to the Qing army, which defeated the rebels, seized the capital, and took over the government in 1644 under the Shunzhi Emperor and his prince regent. While the Qing became a Chinese empire, resistance from Ming rump regimes and the Revolt of the Three Feudatories delayed the complete conquest until 1683, which marked the beginning of the High Qing era. As an emperor of Manchu ethnic origin, the Kangxi Emperor (1661–1722) consolidated control, relished the role of a Confucian ruler, patronised Buddhism, encouraged scholarship, population and economic growth.