Yalu River in the context of "Korea"

North Korea, officially the Democratic People's Republic of Korea (DPRK), is a country in East Asia. It constitutes the northern half of the Korean Peninsula and borders China and Russia to the north at the Yalu (Amnok) and Tumen rivers, and South Korea to the south at the Korean Demilitarized Zone (DMZ). The country's western border is formed by the Yellow Sea, while its eastern border is defined by the Sea of Japan. North Korea, like South Korea, claims to be the sole legitimate government of the Korean Peninsula and adjacent islands. Pyongyang is the capital and largest city.

The Korean Peninsula was first inhabited as early as the Lower Paleolithic period. Its first kingdom was noted in Chinese records in the early 7th century BCE. Following the unification of the Three Kingdoms of Korea into Silla and Balhae in the late 7th century, Korea was ruled by the Goryeo dynasty (918–1392) and the Joseon dynasty (1392–1897). The succeeding Korean Empire (1897–1910) was annexed in 1910 into the Empire of Japan. In 1945, after the Japanese surrender at the end of World War II, Korea was divided into two zones along the 38th parallel, with the north occupied by the Soviet Union and the south occupied by the United States. In 1948, separate governments were formed in Korea: the socialist and Soviet-aligned Democratic People's Republic of Korea in the north, and the capitalist, Western-aligned Republic of Korea in the south. The North Korean invasion of South Korea in 1950 started the Korean War. In 1953, the Korean Armistice Agreement brought about a ceasefire and established a demilitarized zone (DMZ), but no formal peace treaty has ever been signed. Post-war North Korea benefited greatly from economic aid and expertise provided by other Eastern Bloc countries. However, Kim Il Sung, North Korea's first leader, promoted his personal philosophy of Juche as the state ideology. Pyongyang's international isolation sharply accelerated from the 1980s onwards as the Cold War came to an end. The fall of the Soviet Union in 1991 then brought about a sharp decline to the North Korean economy. From 1994 to 1998, North Korea suffered a famine with the population continuing to suffer from malnutrition. In 2024, the DPRK formally abandoned efforts to reunify Korea.

Manchuria is a region in East Asia. Depending on the definition of its extent, Manchuria can refer either to a region falling entirely within present-day China, or to a larger region today divided between Northeast China and the Russian Far East. To differentiate between the two parts following the latter definition, the Russian part is also known as Outer Manchuria (or Russian Manchuria), while the Chinese part is known as Northeast China.

Manchuria is the homeland of the Manchu people. "Manchu" is a name introduced by Hong Taiji of the Qing dynasty in 1636 for the Jurchen people, a Tungusic people.

Korea is a peninsular region in East Asia consisting of the Korean Peninsula, Jeju Island, and smaller islands. Since the end of World War II in Asia in 1945, it has been politically divided at or near the 38th parallel between North Korea (Democratic People's Republic of Korea; DPRK) and South Korea (Republic of Korea; ROK). Both countries proclaimed independence in 1948, and the two countries fought the Korean War from 1950 to 1953. The region is bordered by China to the north and Russia to the northeast, across the Amnok (Yalu) and Duman (Tumen) rivers, and is separated from Japan to the southeast by the Korea Strait.

Known human habitation of the Korean peninsula dates to 40,000 BC. The kingdom of Gojoseon, which according to tradition was founded in 2333 BC, fell to the Han dynasty in 108 BC. It was followed by the Three Kingdoms period, in which Korea was divided into Goguryeo, Baekje, and Silla. In 668 AD, Silla conquered Baekje and Goguryeo with the aid of the Tang dynasty, forming Unified Silla; Balhae succeeded Goguryeo in the north. In the late 9th century, Unified Silla collapsed into three states, beginning the Later Three Kingdoms period. In 918, Goguryeo was resurrected as Goryeo, which achieved what has been called a "true national unification" by Korean historians, as it unified both the Later Three Kingdoms and the ruling class of Balhae after its fall. Goryeo, whose name developed into the modern exonym "Korea", was highly cultured and saw the invention of the first metal movable type. During the 13th century, Goryeo became a vassal state of the Mongol Empire. Goryeo overthrew Mongol rule before falling to a coup led by General Yi Seong-gye, who established the Joseon dynasty in 1392. The first 200 years of Joseon were marked by peace; the Hangul, the Korean alphabet was created and Confucianism became influential. This ended with Japanese and Qing invasions, which brought devastation to Joseon and led to Korean isolationism. After the invasions, an isolated Joseon experienced another nearly 200-year period of peace and prosperity, along with cultural and technological development. In the final years of the 19th century, Japan forced Joseon to open up and Joseon experienced turmoil such as the Kapsin Coup, Donghak Peasant Revolution, and the assassination of Empress Myeongseong. In 1895, Japan defeated China in the First Sino-Japanese War and China lost suzerainty over Korea and Korea was placed under further Japanese influence. In 1897, the centuries old Joseon was replaced by the Korean Empire with the Joseon's last king, Gojong, becoming the Emperor of the Korean Empire. Japan's further victory in the 1904–1905 Russo-Japanese War, expelled Russian influence in Korea and Manchuria. In 1905, the Korean Empire became a protectorate of the Empire of Japan. In 1910, the Empire of Japan officially annexed the Korean peninsula.

Joseon (English: /ˈtʃoʊsʌn/ CHOH-sun; Korean: 조선; Hanja: 朝鮮; MR: Chosŏn; pronounced [tɕo.sʰʌn]; also romanized as Chosun), officially Great Joseon (대조선국; 大朝鮮國; [tʰɛ.dʑo.sʰʌn.ɡuk̚]), was a dynastic kingdom of Korea that existed for 505 years. It was founded by Taejo of Joseon in July 1392 and replaced by the Korean Empire in October 1897. The kingdom was founded after the overthrow of Goryeo in what is today the city of Kaesong. Early on, Korea was retitled and the capital was moved to modern-day Seoul. The kingdom's northernmost borders were expanded to the natural boundaries at the rivers of Amnok and Tuman through the subjugation of the Jurchens.

Over the centuries, Joseon encouraged the entrenchment of Confucian ideals and doctrines in Korean society. Neo-Confucianism was installed as the new state's ideology. Buddhism was accordingly discouraged, and occasionally Buddhists faced persecution. Joseon consolidated its effective rule over the Korean peninsula and saw the height of classical Korean culture, trade, literature, and science and technology. The kingdom was severely weakened by failed Japanese invasions in 1592 and 1598, which were followed by invasions by the Later Jin dynasty in 1627 and the Qing dynasty in 1636–1637. The country pursued an increasingly harsh isolationist policy, becoming known as the "hermit kingdom" in Western literature. After the end of these invasions from Manchuria, Joseon experienced a nearly 200-year period of peace and prosperity, along with cultural and technological development. What power the kingdom recovered during its isolation waned as the 18th century came to a close. Faced with internal strife, power struggles, international pressure, and rebellions at home, the kingdom declined rapidly in the late 19th century.

Northeast China (Chinese: 东北; pinyin: Dōngběi) is a geographical region of China, consisting officially of three provinces Liaoning, Jilin and Heilongjiang. The heartland of the region is the Northeast China Plain, the largest plain in China with an area of over 350,000 km (140,000 sq mi). The region is separated from the Russian Far East to the north and east by the Amur, Argun and Ussuri Rivers; from North Korea to the south by the Yalu and Tumen Rivers; and from the neighboring North China to the west by the Greater Khingan Range and Yan Mountains. It is also bounded by the Bohai Bay and Yellow Sea to the southwest, about 100 km (62 mi) away from East China's Jiaodong Peninsula across the Bohai Strait, due to be connected via a proposed undersea tunnel.

The four prefectures of Inner Mongolia (which is part of North China) east of the Greater Khingan, i.e. Chifeng, Tongliao, Hinggan and Hulunbuir, are sometimes also considered broader parts of Northeast China, and together with the aforementioned three provinces formed what was historically known as Inner Manchuria, in contrast to the Outer Manchuria (or "Outer Northeast" in Chinese literatures) annexed by the Russian Empire during the mid-19th century.

The People's Republic of China (PRC) shares land borders with 14 countries (tied with Russia for the most in the world): North Korea, Russia, Mongolia, Kazakhstan, Kyrgyzstan, Tajikistan, Afghanistan, Pakistan, India, Nepal, Bhutan, Myanmar, Laos, and Vietnam, and with two Special administrative regions of China, Hong Kong and Macao. The land borders, counterclockwise from northeast to southwest, are the China–North Korea border, the eastern segment of the China–Russia border, the China–Mongolia border, the western segment of the China–Russia border, the China–Kazakhstan border, the China–Kyrgyzstan border, the China–Tajikistan border, the China–Afghanistan border, the China–Pakistan border, the western segment of the China–India border (the most contested of the Sino-Indian border dispute), the China–Nepal border, the central segment of the China–India border (Sikkim), the China–Bhutan border, the eastern segment of the China–India border, the China–Myanmar border, the China–Laos border, the China–Vietnam border, a 3-kilometre (1.9 mi) internal border with Macau, a Portuguese territory until 1999, and a 30-kilometre (19 mi) internal border with the special administrative region of Hong Kong, which was a British dependency before 1997.

To the west, China has maritime borders with North Korea, Japan and contested limits with Taiwan and other countries in the South China Sea, among other territorial disputes.

The Tumen River (Chinese: 图们江; pinyin: Túmén Jiāng, Russian: река Туманная, Korean: 두만강; Korean pronunciation: [tumaŋgaŋ]), also known as the Tuman River or Duman River, is a 521-kilometre (324 mi) long river that serves as part of the boundary between China (left shore), North Korea (right) and Russia (left), rising on the slopes of Mount Paektu and flowing into the Sea of Japan. The river has a drainage basin of 33,800 km (13,100 sq mi).

The river flows in northeast Asia, on the border between China and North Korea in its upper reaches, and between North Korea and Russia in its last 17 kilometers (11 mi) before entering the Sea of Japan. The river forms much of the southern border of Jilin Province in Northeast China and the northern borders of North Korea's North Hamgyong and Ryanggang provinces. Paektu Mountain on the Chinese-North Korean border is the source of the river, as well as of the Yalu River. The two rivers and the region of Paektu Mountain between their headwaters form the border between North Korea and China.