The Soviet-sponsored government of North Korea, having failed to conquer its southern neighbor by less violent means, invaded the Republic of Korea on 25 June 1950. When the United States, with other United Nations, came to the aid of the South Koreans, a 3-year war resulted that cost more than 142,000 American battle casualties.
The campaigns set in motion by the invasion of South Korea later were characterized as a "limited war." The fighting was deliberately confined in geographic terms, political decisions placed restrictions upon military strategy, and none of the belligerents, with the exception of the two Korean governments, used its full military potential. But there was nothing limited about the ferocity of the battles.
Erupting from the rivalries of great nations, the Korean War was greatly influenced by domestic conditions rooted deep in the history of Korea, and by the topography of the peninsula where it took place.
Korea is a harsh Asian peninsula inhabited by a hardy, harassed people who rarely if ever had been completely free. War and tragedy form the main theme of Korea's history. Suppression and ill-use have been the heritage of its long-suffering people. Few habitable areas of the earth are more unsuited to large-scale, modern military operations. The rugged landscape, a lack of adequate roads, rail lines, and military harbors, the narrow peninsula, and, not least, climatic extremes restrict and hamper maneuver, severely limit logistic support, and intensify the normal hardships of war.
Jutting from the central Asian mainland, the Korean peninsula has an outline resembling Florida's. In the north, a river-mountain complex separates Korea from Manchuria and the maritime provinces of the USSR. Eastward, across the Sea of Japan, the Japanese islands flank the peninsula. To the west, the Yellow Sea stands between Korea and China. The Korean peninsula stretches south for more than 500 miles, while east and west, it spans only 220 miles at its widest. Thousands of islets, some scarcely more than large rocks, rim its 5,400-mile coastline.
In area, Korea equals the combined states of Tennessee and Kentucky, covering about 85,000 square miles. The facetious claim that Korea, ironed flat, would cover the whole world has an element of truth, for the terrain throughout the peninsula is mountainous. Roads and railways wind through tortuous valleys. Ice-free ports exist on Korea's southern and western coasts, but the latter shore is distinguished by some of the most extreme tidal variations in the world. On the eastern shore, there are only a few adequate harbors. Although geographers place Korea in a temperate zone, the classification hardly mitigates the harsh winters, particularly in the wind-swept northern mountains, or the sweltering, dusty, and no less harsh summers in the south.
The forces shaping Korea into a nation arose from its unfortunate proximity to three powers, China, Japan, and Russia. The periodic surges of ambition in each of these neighbors turned Korea into a battleground and a spoil. Sometimes described as a "dagger pointed at the heart of Japan," Korea became instead Japan's steppingstone to the Asian mainland. For China and, later, Russia, Korea was a back gate both to be locked against intruders and to be opened during any opportunity for expansion. Korea's ice-free ports fronting the Sea of Japan were especially coveted by the Russians. Korea therefore has seldom been completely free of domination by one of its stronger neighbors. 
China reached the Korean scene first, making its impact felt on northern Korea several centuries before the beginning of the Christian era. By the 7th century, A.D., the Chinese had forced their thought, customs, and manners into the Korean culture and had turned Korea into a virtual satellite. Late in that century, a native dynasty, Chinese-controlled, unified the peninsula. Before then Japan had occasionally invaded southern Korea, but with little lasting effect. Badly defeated by the Koreans in 663 A.D., Japan retired for nearly a thousand years.
Like China, Korea endured the Mongol armies in the 13th century. For nearly a hundred years the savages from the steppes ruled and ravaged Korea. Kublai Khan launched two abortive invasions of Japan from Korea, ruthlessly squandering Korean lives and property in his depredations. With the gradual dissipation of Mongol power by the mid-14th century, Korea again basked in the reflected glory of a revitalized China. Adapting Chinese culture to their own talents, the Koreans
 Unless otherwise cited, material on Korea's history is based on the following: H. Frederick Nelson, Korea and the Old Orders in Eastern Asia (Baton Rouge: Louisiana State University Press, 1946); Yoshi Kuno, Japanese Expansion on the Asiatic Continent, 2 vols. (Berkeley: University of California Press, 1937), vol. I; Ernest W. Clement, A Short History of Japan (Tokyo: Christian Literature Society, 1926); Andrew Grajdanzev, Modern Korea (New York: The John Day Company, 1944); Cornelius Osgood, The Koreans and Their Culture (New York: Ronald Press, 1951); Harold M, Vinacke, A History of the Far East in Modern Times (New York: Appleton-Century-Crofts, 1941), pp. 123-24; A. Whitney Griswold, Far Eastern Policy of the United States (New York: Harcourt, Brace, 1938); George M. McCune and John A. Harrison, Korean-American Relations, 3 vols. (Berkeley: University of California Press, 1951), vol. I; Tyler Dennett, Americans in Eastern Asia (New York: The Macmillan Company, 1922).
flourished. Skilled artisans, craftsmen, and inventors, as well as philosophers and scholars, brought Korea a level of civilization rivaling that of China. But the Japanese violently disrupted this happy era. In a brutal expedition beginning in 1592, Japanese samurai under the brilliant Hideyoshi pillaged the peninsula for seven years. Aided by China, the Koreans eventually expelled the Japanese, but their home had become a wasteland. Their best artisans and scholars, along with the greater part of their portable treasure, were taken home by the Japanese.
In the following centuries, Korea kept loose cultural and political ties with China but withdrew from contact with the rest of the world. It never again reached the level of civilization the Japanese had destroyed. When Western influence spread to Asia in the 19th century, China's peculiar relationship with Korea baffled the West. Western efforts to trade with Korea were thwarted by this misunderstanding. The Koreans received Western overtures coldly. They impartially murdered French missionaries and American and Dutch seamen. Several punitive expeditions by these Western nations against Korea failed to improve relations.
Unfortunately for Korea's privacy, in 1860 Russia reached Korea's borders and later in the century westernization again whetted Japan's appetite for territorial expansion. With China, Japan, and Russia fighting for control of Korea throughout the rest of the 19th century, the Korean people had little chance to learn self-government. They remained separate from the modern world emerging around them.
Japan won Korea by defeating China and Russia, in turn, in short but decisive wars. In the Sino-Japanese War of 1894-95 Japan used Western military techniques to beat its larger but tradition-bound enemy. Ten years later, Japan astounded the world by defeating Russia. Having occupied Korea to fight Russia, Japan left its troops there. Ignoring Korean objections, Japan disbanded the Korean Army and abolished the Korean Department of Post and Communications. It allowed a semblance of self-rule in Korea for several years, but remained the real master. Japanese seizure of governmental functions, the forced abdication of Korea's Emperor, and encroachment in all aspects of Korean society culminated in an agreement in July 1907 placing Korea completely under Japanese control. The annexation of Korea by Japan in August 1910 was simply a formality. 
In the quarter century before the Japanese take-over, the United States showed a mild interest in Korea and made some effort to support Korean independence, at least in principle. In 1882, an American naval officer, Commodore Robert W. Shufeldt, negotiated a commercial treaty with the Korean Emperor. The result of four years' effort, this treaty was achieved through the reluctant good offices of the Chinese
 An account of Korean life under the Japanese can be found in History of the Occupation of Korea, August 1945-May 1948, 3 vols. (hereafter cited as History of Occupation of Korea), prepared in 1948 by historians of the XXIV Corps, vol. I, ch. 2, copy in OCMH.
Government. It provided for exchange of diplomatic representatives, protection of navigation and of United States citizens, extraterritoriality, and trade under a most-favored nation clause. The treaty could have given the United States overriding influence in Korea. But when the Emperor sought an American foreign affairs adviser and Army military advisers, the United States moved slowly. The matter dragged on for several years. The American representative in Korea repeatedly appealed to Washington for action. Although requested in 1884, military advisers reached Korea only in 1888.
The United States treated Korea casually in the late 19th century. Its only significance lay in the effect it had upon relationships with other major powers in the Far East. According to one authority, "The Korean Government was in the position of an incompetent defective not yet committed to guardianship. The United States was her only disinterested friend-but had no intention of becoming her guardian." 
When the Japanese took over Korea, the United States made no objection. President Theodore Roosevelt remarked, "We cannot possibly interfere for the Koreans against Japan. ... They could not strike one blow in their own defense." On 29 July 1905, Secretary of War William H. Taft negotiated a secret "agreed memorandum" with the Japanese Prime Minister. The United States approved Japan's "suzerainty over" Korea in return for its pledge not to interfere with American interests in the Philippine Islands. The Korean Emperor's appeal to the United States for help under the "good offices" clauses of the Shufeldt Treaty fell on deaf ears. 
Between 1905 and 1910, uprisings and rebellions erupted frequently throughout Korea. Japan crushed them with efficient savagery. The Koreans had few weapons, and Japan was a powerful and merciless nation. According to Japanese statistics, 14,566 Korean "rebels" were killed between July 1907 and December 1908. By 1910, when Japan formally annexed Korea, little open resistance remained in the land; and no Western nation spoke out against Japan's seizure of the peninsula.
Complete suppression marked the ensuing thirty-five years of Japanese rule. The Japanese exploited the people and the land. But they also modernized Korea, building highways, railroads, dams, and factories. Much of this development was designed for military use. The port of Pusan, for example, was built for military, rather than commercial, reasons; and the rail line running from Pusan north to the Manchurian border had much more military than commercial value.
The Japanese integrated Korean industry into their own economy. Korea became completely dependent upon Japan for semi-manufactured commodities, for repair parts, and for markets. Many key Korean plants produced only parts used in the final assembly of products in Japan. As Japan embarked on its program of conquest in Asia in the 1930's, the Japanese turned Korean in
 Dennett, Americans in Eastern Asia, p. 495.
 (1) Griswold, Far Eastern Policy of the United States, p. 125. (2) Robert T. Oliver, Verdict in Korea (State College, Pa.: Bald Eagle Press, 1952), p. 37.
dustry almost exclusively to military use. The heavy, sustained use of machinery without adequate maintenance during World War II ruined Korean factories and equipment. The use of almost all chemical production, especially of nitrogen, in behalf of Japan's war effort caused severe soil depletion in Korea. 
Banning Koreans from responsible positions and from educational opportunities, the Japanese controlled key governmental and economic functions. Comprising only 3 percent of the population of Korea, the 750,000 Japanese residents were absolute masters of the country. Nearly 80 percent of the Korean people could neither read nor write. 
The Koreans deeply resented Japanese exploitation. Judged in Japanese courts under Japanese laws, they received severe sentences for minor offenses, more severe than those given Japanese for similar infractions. The Japanese-controlled Bank of Chosen charged Koreans interest rates 25 percent higher than those assessed Japanese competitors. The Korean national debt increased thirty-fold between 1910 and 1945, and the taxation of Koreans was oppressive. In most industries, Japanese received twice as much as Koreans doing the same work. Large numbers of farms were transferred from Korean to Japanese owners. 
Despite iron-handed Japanese rule that sought to crush Korean national aspirations, the flame of patriotism and independence remained alive in Korea. Revolutionary groups and movements sustained the Korean hope for freedom, defying the Japanese whenever possible. One strong group working to free Korea from alien rule called itself the "Provisional Government of the Republic of Great Korea." It originated on 1 March 1919 when a declaration of independence, signed by Korean students, was read before a student gathering in Seoul. The Japanese ruthlessly hunted down the instigators of this declaration, and many patriots fled Korea to escape torture and death. On 10 April 19l9 some of these refugees met in Shanghai and established the Provisional Government. Dr. Syngman Rhee headed the group as Premier. After the Manchurian incident in 1931, the Provisional Government moved to Nanking and, later, to Chungking.
This group sought to achieve complete independence for Korea and to establish itself as the Korean Government. Differences on how these goals should be reached brought frequent clashes in the leadership of the Korean Provisional Government. Two men, Rhee and Kim Koo, emerged at the top. When Kim Koo became Premier in the mid-1930's, Rhee served as unofficial representative of the Provisional Government in the United States. The group acquired a considerable following among Koreans in the United States and China and attracted widespread passive support within Korea. Both Rhee and Kim were revered by the Korean people. 
A strong Korean Communist party also
 Testimony of Hon. Paul G. Hoffman Administrator of the Economic Cooperation Administration (ECA) before the House Committee on Foreign Affairs, 81st Congress, 1st Session, 8 June 1949, in House Report No. 962, Korean Aid, H.R. 5330, June 1949, p. 9.
 History of Occupation of Korea, vol. I, ch. 2.
 Ibid., pp. 46-48.
sprang up in Korea. Organized in 1925, it pushed the underground movement against Japan. Communist power in Korea grew under the well-organized leadership of the anti-Japanese underground. The Korean Communists were in contact with the Russian Communists through the Far Eastern Division of the Comintern. It is believed, however, that, owing to a secret agreement with Japan, the Russians abstained from encouraging too greatly the Communists in Korea during Japanese occupation. Many Communist Koreans took refuge in Manchuria, China, and Russia. 
In this setting of turbulent and long-suppressed patriotic emotions, it was inevitable that the political void caused by the fall of the Japanese Empire at the end of World War II should touch off a struggle for power.
When World War II began, Korea was regarded by the Allies as a victim
of, not a party to, Japanese aggression. One of the earliest signs that the Allied Powers were concerned about Korea appeared in a Joint statement by the United States, China, and Great Britain in December 1943, after the Cairo Conference, which said: "The aforesaid three great powers, mindful of the enslavement of the people of Korea, are determined that in due course Korea shall become free and independent." 
Divergencies between American and Russian policies appearing in the latter stages of World War II affected Korea. The destruction of the Axis in 1945 left
 Ibid., vol. II, ch. 2, pp. 7-20.
 Department of State, Foreign Relations of the United States: The Conferences at Cairo and Tehran, 1943, Dept., of State Publication 7187 (Washington, 1961), p. 448.
power vacuums in many areas of the world and brought the differences between the United States and the Soviet Union into sharp focus. Countries newly freed from German or Japanese domination assumed significance as possible targets of clashing American-Soviet interests.
Unlike the Soviet Union, the United States attached little importance to Korea as a strategic area. Korea supported a relatively small population, and had neither important industrial facilities nor many natural resources. If at some future date Korea fell into hands unfriendly to the United States, the United States recognized that the occupation of Japan might be hampered and American freedom of movement might be restricted in the general area. But with China in 1945 under control of a friendly government, such a situation appeared unlikely. Russia, on the other hand, maintained its traditional regard for Korea as a strategic area. As later events demonstrated, the Soviet Union would not countenance control of Korea by another power and sought to control Korea itself.
President Franklin D. Roosevelt and Premier Josef V. Stalin at the Yalta Conference in 1945 touched upon Korea's future. Roosevelt advocated a trusteeship for Korea administered by the United States, the Soviet Union, and China. Looking at American experience in the Philippines, he surmised that such a trusteeship might last for twenty or thirty years. Stalin said he believed that Great Britain should also be a trustee. No actual mention of Korea was made in the document recording the agreements at Yalta. The secret protocol developed by Roosevelt and Stalin and agreed to by Prime Minister Winston S. Churchill only provided territorial and other concessions to the USSR in the Far East as conditions for Russian entrance into the war against Japan after the defeat of Germany. Later, soon after Roosevelt's death, Stalin told Harry Hopkins, President Harry S. Truman's representative in Moscow, that Russia was committed to the policy of a 4-power trusteeship for Korea. 
Though American military planners ostensibly paid little attention to Korea, they had Korea in mind. On 25 July 1945, the Army Chief of Staff, General of the Army George C. Marshall, sent a note to President Truman at Potsdam, advising him that some guidance on handling Korea would assist the Joint Chiefs of Staff. General of the Army Douglas MacArthur, Commander in Chief of the United States Army Forces, Pacific, had already received instructions to prepare for occupying Japan, and shortly before Potsdam these orders were broadened to include Korea. In response to the additional directive, General MacArthur suggested that Tokyo and Seoul have first priority for occupation, Pusan second priority, and the Kunsan area on Korea's west coast, third priority. General Marshall then informed the President that MacArthur should be able to land a division at Pusan within a short time of the end of the war. The other strategic areas in Korea, Mar-
 (1) Department of State, Foreign Relations of the United States: The Conference at Malta and Yalta, 1945, Dept. of State Publication 6199 (Washington, 1955), pp. 770, 984. (2) Harry S. Truman, Memoirs, 2 vols., vol. II, Years of Trial and Hope (New York: Doubleday and Co., Inc., 1956), PP 316-17.
shall added, were Seoul, near the west coast, and Ch'ongjin, in the north on the Sea of Japan. Marshall expected that the Russians, if they participated in the occupation, would occupy Ch'ongjin and would undoubtedly move into Manchuria and perhaps into north China. He considered it desirable, therefore, to establish early control over any areas to be held by the United States. 
Korea was only briefly considered at the Potsdam conference. Among the questions discussed were the Soviet timetable for entering the war in the Pacific and the Allied proclamation demanding Japan's unconditional surrender. Looking ahead to the surrender of the Japanese on the Asiatic mainland, the Allied military representatives drew a tentative line across the map of Manchuria, above which the Soviet Union was to accept surrender of Japanese forces. No mention was at first made of Korea. But since thousands of Japanese troops were stationed in Korea, there was a later discussion of Allied operations in that area. 
At Potsdam, the chief of the Russian General Staff told General Marshall that Russia would attack Korea after declaring war on Japan. He asked whether the Americans could operate against Korean shores in co-ordination with this offensive. General Marshall told him that the United States planned no amphibious operation against Korea until Japan had been brought under control and Japanese strength in South Korea was destroyed. Although the Chiefs of Staff developed ideas concerning the partition of Korea, Manchuria, and the Sea of Japan into U.S. and USSR zones, these had no connection with the later decisions that partitioned Korea into northern and southern areas. 
Russian entry into the war against Japan on 9 August, and signs of imminent Japanese collapse on 10 August 1945 changed U.S. Army planning from defeating Japan to accepting its surrender. Military planners in the War Department Operations Division began to outline surrender procedures in General Order No. 1, which General MacArthur would transmit to the Japanese Government after its surrender. The first paragraph of the order specified the nations and commands that were to accept the surrender of Japanese forces throughout the Far East. 
The Policy Section of the Strategy and Policy Group in the Operations Division drafted the initial version of the order.
 (1) Lt. Paul C. McGrath, U.S. Army in the Korean Conflict, n.d., pp. 26-27, OCMH draft MS. (2) Memo, Marshall for President (delivered at Potsdam), 25 Jul. 45, file OPD 370.9, Case 17/8.
 (1) Interv., 1st Lt. Paul C. McGrath with Vice Adm. M. B. Gardner, 28 Jan 53, the Pentagon. (2) Interv., McGrath with Lt. Gen. Charles P. Cabell, Dir. of the Joint Staff, JCS, OSD, 27 Jan 53. Both in OCMH.
 (1) McGrath, U.S. Army in the Korean Conflict, pp. 24-25. (2) History of Occupation of Korea. vol. II, ch. 3, p. 6. (3) Roy E. Appleman, South to the Naktong, North to the Yalu, UNITED STATES ARMY IN THE KOREAN WAR (Washington, 1961), pp. 2-3. (4) See also discussions of 24 and 26 July in Department of State, Foreign Relations of the United States: The Conference at Berlin (The Potsdam Conference), 1945, 2 vols., Dept. of State Publications 7015, 7163 (Washington, 1960), II, 345-52, 408-15. (5) There was widespread misconception that the division of Korea had been agreed upon at the high-level conference of the Big Three. In June 1946, the Institute of Pacific Relations published a categorical statement that this agreement had been made at Yalta. The New York Times in October 1946 named Potsdam as the place where the agreement had been made.
 McGrath, U.S. Army in the Korean Conflict, p. 42.
Under pressure to produce a paper as quickly as possible, members of the Policy Section began work late at night on 10 August. They discussed possible surrender zones, the allocation of American, British, Chinese, and Russian occupation troops to accept the surrender in the zone most convenient to them, the means of actually taking the surrender of the widely scattered Japanese military forces, and the position of Russia in the Far East. They quickly decided to include both provisions for splitting up the entire Far East for the surrender and definitions of the geographical limits of those zones. 
The Chief of the Policy Section, Col. Charles H. Bonesteel, had thirty minutes in which to dictate Paragraph 1 to a secretary, for the Joint Staff Planners and the State-War-Navy Coordinating Committee were impatiently awaiting the result of his work. Colonel Bonesteel thus somewhat hastily decided who would accept the Japanese surrender. His thoughts, with very slight revision, were incorporated into the final directive. 
Bonesteel's prime consideration was to establish a surrender line as far north as he thought the Soviets would accept. He knew that Russian troops could reach the southern tip of Korea before American troops could arrive. He knew also that the Russians were on the verge of moving into Korea, or were already there. The nearest American troops to Korea were on Okinawa, 600 miles away. His problem therefore was to compose a surrender arrangement which, while acceptable to the Russians, would at the same time prevent them from seizing all of Korea. If they refused to confine their advance to North Korea, the United States would be unable to stop them.
At first Bonesteel had thought of surrender zones conforming to the provincial boundary lines. But the only map he had in his office was hardly adequate for this sort of distinction. The 38th Parallel, he noted, cut Korea approximately through the middle. If this line was agreeable to President Truman and to Generalissimo Stalin, it would place Seoul and a nearby prisoner of war camp in American hands. It would also leave enough land to be apportioned to the Chinese and British if some sort of quadripartite administration became necessary. Thus he decided to use the 38th Parallel as a hypothetical line dividing the zones within which Japanese forces in Korea would surrender to appointed American and Russian authorities.
The determination of the surrender zones for the Pacific involved other countries besides Korea. Since the job had to be done in a hurry, Colonel Bonesteel had the paragraphs of the general order rushed through the Chief of the Strategy and Policy Group, Brig. Gen. George A. Lincoln, to the Joint Staff Planners who were meeting in an all-night session. This channel was the same as for all important military policy papers in 1945. Drafts were routed in turn through General Lincoln, the Joint Planners, the State-War-Navy Coordinating Committee, the Joint Chiefs of Staff, and the Secretaries of State, War, and Navy, until they finally reached the President.
 (1) Ibid. (2) See also Truman, Memoirs, II, 317.
 The remainder of this subsection is based on McGrath, U.S. Army in the Korean Conflict, pp. 40-53.
When Bonesteel's draft paper reached the Joint Planners in the pre-dawn hours of 11 August, Admiral M. B. Gardner suggested moving the surrender line north to the 39th Parallel, a recommendation that the planners believed the Navy Secretary, James C. Forrestal, favored. Gardner pointed out that the 39th Parallel would place Dairen in the military zone to be occupied by the Americans. General Lincoln, however, felt that the Russians would hardly accept a surrender line that barred them from Dairen and other parts of the Liaotung Peninsula; besides, American units would have great difficulty reaching the Manchurian port ahead of the Russians. Calling Assistant Secretary of State James Dunn, Lincoln ascertained that his opinion was shared. Mr. Dunn believed that Korea was more important politically to the United States than Dairen, and he felt this to be the view of Secretary of State James F. Byrnes. As a result, the 38th Parallel remained in the draft when the Joint Planners handed the general order to the State-War-Navy Coordinating Committee.
While General Lincoln was shepherding the document through the State-War-Navy Coordinating Committee on 11 and 12 August, the Russians invaded Korea, landing on the northeast coast near Rashin. Russian troops then poured out of the maritime provinces of Siberia, down the Korean peninsula, and into the Kaesong-Ch'unch'on area above Seoul, where they looted much equipment, including locomotives and rolling stock. Reports of the Russian troop movements reaching Washington underscored the need for concurrence in the proposed general order. Otherwise, the Russian advance would render academic the American acceptance of the Japanese surrender in southern Korea. At the same time, swift Russian troop movements into key areas of southern Manchuria eliminated the possibility of including Dairen in the American surrender zone.
Between 11 and 14 August, the State-War-Navy Coordinating Committee and the Joint Chiefs of Staff discussed the wording of the surrender instrument. Meanwhile, General MacArthur informed the Joint Chiefs of Staff that he would adhere to three priorities for the use of the forces under his command. After the Japanese surrender, the occupation of Japan would come first, Korea second, China third.
In Washington, the War Department Operations Division rephrased General Order No. 1 to the satisfaction of the Joint Chiefs of Staff and the heads of the State, War, and Navy Departments. On 15 August 1945, clean copies of the draft order were sent to Fleet Admiral William D. Leahy's White House office. Within a few hours President Truman gave his approval, directing at the same time that General Order No. 1 be sent also to the capitals of Great Britain and the USSR with requests for concurrence by the heads of those states. The Joint Chiefs of Staff telegraphed the general order to General MacArthur and directed that he furnish an estimated time schedule for the occupation of a port in Korea.
Among the items it specified, General Order No. 1 stated that Japanese forces north of the 38th Parallel in Korea would surrender to the Russian commander, while those south of the parallel
would surrender to the commanding general of the U.S. expeditionary forces. As Washington waited for the Moscow reaction to President Truman's message, there was a short period of suspense. Russian troops had entered Korea three days before the President accepted the draft of General Order No. 1. If the Russians failed to accept the proposal, and if Russian troops occupied Seoul, General Lincoln suggested that American occupation forces move into Pusan.
Stalin replied to President Truman on 16 August 1945. He said nothing specifically about the 38th Parallel but offered no objection to the substance of the President's message. He asked that the general order be "corrected" to authorize Russian forces to accept the surrender of the Japanese in the northern half of Hokkaido. Stalin also reminded the President that the Liaotung Peninsula, upon which Dairen and Port Arthur are located, was part of Manchuria and thus within the USSR military zone. Though President Truman parried Stalin's proposal to place Russian forces on Hokkaido, Stalin's message settled the surrender zones in Korea and canceled American plans to land troops at Dairen.
The new dividing line, about 190 miles across the peninsula, sliced across Korea without regard for political boundaries, geographical features, waterways, or paths of commerce. The 38th Parallel cut more than 75 streams and 12 rivers, intersected many high ridges at variant angles, severed 181 small cart roads, 104 country roads, 15 provincial all-weather roads, 8 better-class highways, and 6 north-south rail lines.  It was, in fact, an arbitrary separation.
South of the 38th Parallel, the American zone covered 37,000 square miles and held an estimated 21,000,000 persons. North of the line of latitude, the USSR zone totaled 48,000 square miles and had about 9,000,000 people.  Of the 20 principal Korean cities, 12 lay within the American zone, including Seoul, the largest, with a population of nearly 2,000,000. The American zone included 6 of Korea's 13 provinces in their entirety, the major part of 2 more, and a small part of another. The two areas, North and South Korea, complemented each other both agriculturally and industrially. South Korea was mainly a farming area, where fully two-thirds of the inhabitants worked the land. It possessed three times as much irrigated rice land as the northern area, and furnished food for the north. But North Korea furnished the fertilizer for the southern rice fields, and the largest nitrogenous fertilizer plant in the Far East was in Hungnam. Although North Korea also had a high level of agricultural production, it was deficient in some crops. The barrier imposed serious adverse effects on both zones. 
 Shannon C. McCune, "Physical Basis for Korean Boundaries," Far Eastern Quarterly, No. 5 (May 946), pp. 286-87.
 (1) Andrew Grajdanzev, "Korean Divided," Far Eastern Survey, XIV (October 1945), 282. (2) "History of Occupation of Korea", vol. I, ch. 4, p. 16.
 The closing paragraphs of this chapter are based on information in (1) Testimony of Hoffman, 8 June 1949, House Report 962, June 1949, and (2) George A. McCune, Korea Today (Cambridge: Harvard University Press, 1950), pp. 52-56.
South Korea had in 1940 turned out about 74 percent of Korea's light consumer goods and processed products. Its industry consisted of some large and many small plants producing textiles, rubber products, hardware, and ceramics. Many of these plants had been built to process raw materials from North Korea.
North Korea, a largely mountainous region, held valuable mineral deposits, especially coal. Excellent hydroelectric plants, constructed during the last ten years of Japanese domination, ranked with the largest and best in the world. Because of its power resources, North Korea housed almost all of Korea's heavy industry, including several rolling mills and a highly developed chemical industry. In 1940, North Korea produced 86 percent of Korea's heavy manufactured goods. The only petroleum processing plant in the country, a major installation designed to serve all of Korea, was located in the north, as were seven of eight cement plants. Almost all the electrical power used by South Korea came from the north, as did iron, steel, wood pulp, and industrial chemicals needed by South Korea's light industry.
Sharp differences between north and south had traditionally been part of the Korean scene. South Koreans considered their northern neighbors crude and culturally backward. North Koreans viewed southerners as lazy schemers. During the Japanese occupation Koreans in the north had been much less tractable than those in the south. Differences in farming accounted for some of the social differences in the two zones. A dry-field type of farming in the north opposed a rice-culture area in the south to produce marked variations in points of view. In the south were more small farms and a high tenancy rate, while in the north larger farms and more owner-farmers prevailed. Those differences the 38th Parallel promised to exacerbate.