Question: When did the US go to war with the country where Ofusato died?

full_context: Document 1: Korean War: The Battle of Osan, the first significant American engagement of the Korean War, involved the 540-soldier Task Force Smith, which was a small forward element of the 24th Infantry Division which had been flown in from Japan. On 5 July 1950, Task Force Smith attacked the North Koreans at Osan but without weapons capable of destroying the North Koreans' tanks. They were unsuccessful; the result was 180 dead, wounded, or taken prisoner. The KPA progressed southwards, pushing back the US force at Pyongtaek, Chonan, and Chochiwon, forcing the 24th Division's retreat to Taejeon, which the KPA captured in the Battle of Taejon; the 24th Division suffered 3,602 dead and wounded and 2,962 captured, including the Division's Commander, Major General William F. Dean.
Document 2: Yuan dynasty: When Yesün Temür died in Shangdu in 1328, Tugh Temür was recalled to Khanbaliq by the Qipchaq commander El Temür. He was installed as the emperor (Emperor Wenzong) in Khanbaliq, while Yesün Temür's son Ragibagh succeeded to the throne in Shangdu with the support of Yesün Temür's favorite retainer Dawlat Shah. Gaining support from princes and officers in Northern China and some other parts of the dynasty, Khanbaliq-based Tugh Temür eventually won the civil war against Ragibagh known as the War of the Two Capitals. Afterwards, Tugh Temür abdicated in favour of his brother Kusala, who was backed by Chagatai Khan Eljigidey, and announced Khanbaliq's intent to welcome him. However, Kusala suddenly died only four days after a banquet with Tugh Temür. He was supposedly killed with poison by El Temür, and Tugh Temür then remounted the throne. Tugh Temür also managed to send delegates to the western Mongol khanates such as Golden Horde and Ilkhanate to be accepted as the suzerain of Mongol world. However, he was mainly a puppet of the powerful official El Temür during his latter three-year reign. El Temür purged pro-Kusala officials and brought power to warlords, whose despotic rule clearly marked the decline of the dynasty.
Document 3: Korean War: On 25 November at the Korean western front, the PVA 13th Army Group attacked and overran the ROK II Corps at the Battle of the Ch'ongch'on River, and then decimated the US 2nd Infantry Division on the UN forces' right flank. The UN Command retreated; the U.S. Eighth Army's retreat (the longest in US Army history) was made possible because of the Turkish Brigade's successful, but very costly, rear-guard delaying action near Kunuri that slowed the PVA attack for two days (27–29 November). On 27 November at the Korean eastern front, a U.S. 7th Infantry Division Regimental Combat Team (3,000 soldiers) and the U.S. 1st Marine Division (12,000–15,000 marines) were unprepared for the PVA 9th Army Group's three-pronged encirclement tactics at the Battle of Chosin Reservoir, but they managed to escape under Air Force and X Corps support fire—albeit with some 15,000 collective casualties.
Document 4: United States in the Korean War: In response to North Korea's invasion into South Korea the United Nations convened to formulate a response. The U.N. demanded North Korea's immediate withdrawal and, when this was not met, United States Army General Douglas MacArthur was appointed supreme commander of U.N. forces. To halt the rapid progress of North Korean forces into the south Task Force Smith was deployed to the Korean front from Japan. Task Force Smith consisted of U.S. Army officers and regiments of the Army's 24th Infantry Division that were stationed in Japan as occupational forces. Unfortunately the 24th were under trained, poorly supplied, and outnumbered. The 24th offered very little resistance against the North Korean advance. American and South Korean troops were pushed south and in late July 1950 Task Force Smith was overrun in the city of Taejon. Troops from the Army's 25th Infantry Division were deployed to Taejon to establish a new line and pullout the decimated 24th I.D. This addition of combat troops did not stop the North Korean advance and both American and South Korean troops were pushed further south.
Document 5: Sino-Tibetan relations during the Ming dynasty: Sonam Gyatso, after being granted the grandiose title by Altan Khan, departed for Tibet. Before he left, he sent a letter and gifts to the Ming Chinese official Zhang Juzheng (1525–1582), which arrived on March 12, 1579. Sometime in August or September of that year, Sonam Gyatso's representative stationed with Altan Khan received a return letter and gift from the Wanli Emperor (r. 1572–1620), who also conferred upon Sonam Gyatso a title; this was the first official contact between a Dalai Lama and a government of China. However, Laird states that when Wanli invited him to Beijing, the Dalai Lama declined the offer due to a prior commitment, even though he was only 400 km (250 mi) from Beijing. Laird adds that "the power of the Ming emperor did not reach very far at the time." Although not recorded in any official Chinese records, Sonam Gyatso's biography states that Wanli again conferred titles on Sonam Gyatso in 1588, and invited him to Beijing for a second time, but Sonam Gyatso was unable to visit China as he died the same year in Mongolia working with Altan Khan's son to further the spread of Buddhism.
Document 6: Sino-Tibetan relations during the Ming dynasty: Wang and Nyima argue that the Ming emperor sent edicts to Tibet twice in the second year of the Ming dynasty, and demonstrated that he viewed Tibet as a significant region to pacify by urging various Tibetan tribes to submit to the authority of the Ming court. They note that at the same time, the Mongol Prince Punala, who had inherited his position as ruler of areas of Tibet, went to Nanjing in 1371 to pay tribute and show his allegiance to the Ming court, bringing with him the seal of authority issued by the Yuan court. They also state that since successors of lamas granted the title of "prince" had to travel to the Ming court to renew this title, and since lamas called themselves princes, the Ming court therefore had "full sovereignty over Tibet." They state that the Ming dynasty, by issuing imperial edicts to invite ex-Yuan officials to the court for official positions in the early years of its founding, won submission from ex-Yuan religious and administrative leaders in the Tibetan areas, and thereby incorporated Tibetan areas into the rule of the Ming court. Thus, they conclude, the Ming court won the power to rule Tibetan areas formerly under the rule of the Yuan dynasty.
Document 7: Ofusato: He presented himself to the Chinese imperial court for recognition in 1388. After Ofusato died while in Korea, his brother Yafuso seized power and sought formal recognition from China.
Document 8: Korean War: After the Incheon landing, the 1st Cavalry Division began its northward advance from the Pusan Perimeter. "Task Force Lynch" (after Lieutenant Colonel James H. Lynch), 3rd Battalion, 7th Cavalry Regiment, and two 70th Tank Battalion units (Charlie Company and the Intelligence–Reconnaissance Platoon) effected the "Pusan Perimeter Breakout" through 106.4 miles (171.2 km) of enemy territory to join the 7th Infantry Division at Osan. The X Corps rapidly defeated the KPA defenders around Seoul, thus threatening to trap the main KPA force in Southern Korea.
Document 9: Korean War: In the resulting Battle of Pusan Perimeter (August–September 1950), the U.S. Army withstood KPA attacks meant to capture the city at the Naktong Bulge, P'ohang-dong, and Taegu. The United States Air Force (USAF) interrupted KPA logistics with 40 daily ground support sorties that destroyed 32 bridges, halting most daytime road and rail traffic. KPA forces were forced to hide in tunnels by day and move only at night. To deny matériel to the KPA, the USAF destroyed logistics depots, petroleum refineries, and harbors, while the U.S. Navy air forces attacked transport hubs. Consequently, the over-extended KPA could not be supplied throughout the south. On 27 August, 67th Fighter Squadron aircraft mistakenly attacked facilities in Chinese territory and the Soviet Union called the UN Security Council's attention to China's complaint about the incident. The US proposed that a commission of India and Sweden determine what the US should pay in compensation but the Soviets vetoed the US proposal.
Document 10: United States in the Korean War: The first battle the Americans entered in the Korean War was the Battle of Osan, where about four hundred strong landed in Pusan airport on the first of July. The American troops were sent off to Taejon the next morning where Major General John H. Church the head of U.S. field headquarters was confident in the US troop's strengths to push back the North Koreans. On July fifth the troops were finally put to the test when North Korean tanks crept towards Osan. The four hundred infantryman of the U.S. also called Task Force Smith opened fire on the North Koreans at 8: 16 am. Only four of the North Korean tanks were destroyed and twenty - nine kept moving forward breaking the US line. At the end of the battle only two more North Korean Tanks and two regiments of North Korean infantry were destroyed. The US had lost the battle, revealing that the mere sight of US troops would not reverse the military balance in Korea. By early August, the North Korean troops had pushed back the US and South Korean troops all the way to Naktong River, which is located about thirty miles from Pusan. The two weeks of fighting following this resulted in the most casualties of US troops than any other equivalent period of this war. However, during this time the US pushed supplies and personnel to Korea and by the end of July South Koreans and US troops outnumbered the North Koreans, although the North had pushed back the US and South by an amazing amount the North had suffered over fifty thousand casualties. Also because North Koreas supply lines were so lengthy and with the US in control of the water and air replenishing there losses were slow.
Document 11: Battle of Taejon: The Battle of Taejon (14–21 July 1950) was an early battle of the Korean War, between American and North Korean forces. Forces of the United States Army attempted to defend the headquarters of the 24th Infantry Division. The 24th Infantry Division was overwhelmed by numerically superior forces of the Korean People's Army (KPA) at the major city and transportation hub of Taejon. The 24th Infantry Division's regiments were already exhausted from the previous two weeks of delaying actions to stem the advance of the KPA.
Document 12: Bruneian Empire: After the death of its emperor, Hayam Wuruk, Majapahit entered a state of decline and was unable to control its overseas possessions. This opened the opportunity for Bruneian kings to expand their influence. Chinese Ming emperor Yongle, after ascending to the throne in 1403, immediately dispatched envoys to various countries, inviting them to pay tribute to the Chinese court. Brunei immediately got involved in the lucrative tributary system with China.
Document 13: Korean War: Meanwhile, U.S. garrisons in Japan continually dispatched soldiers and matériel to reinforce defenders in the Pusan Perimeter. Tank battalions deployed to Korea directly from the U.S. mainland from the port of San Francisco to the port of Pusan, the largest Korean port. By late August, the Pusan Perimeter had some 500 medium tanks battle-ready. In early September 1950, ROK Army and UN Command forces outnumbered the KPA 180,000 to 100,000 soldiers. The UN forces, once prepared, counterattacked and broke out of the Pusan Perimeter.
Document 14: Nanjing: As the center of the empire, early-Ming Nanjing had worldwide connections. It was home of the admiral Zheng He, who went to sail the Pacific and Indian Oceans, and it was visited by foreign dignitaries, such as a king from Borneo (Boni 渤泥), who died during his visit to China in 1408. The Tomb of the King of Boni, with a spirit way and a tortoise stele, was discovered in Yuhuatai District (south of the walled city) in 1958, and has been restored.
Document 15: Yuan dynasty: When the Mongols placed the Uighurs of the Kingdom of Qocho over the Koreans at the court the Korean King objected, then the Mongol Emperor Kublai Khan rebuked the Korean King, saying that the Uighur King of Qocho was ranked higher than the Karluk Kara-Khanid ruler, who in turn was ranked higher than the Korean King, who was ranked last, because the Uighurs surrendered to the Mongols first, the Karluks surrendered after the Uighurs, and the Koreans surrendered last, and that the Uighurs surrendered peacefully without violently resisting.
ground_truth: the Battle of Osan
sub_queries: In what place did Ofusato die? Answer: Korea
when did the us go to war with Korea Answer: the Battle of Osan