Chapters:

1. To Korea by Sea
2. Policy and its Instruments
3. War Begins
4. Help on the Way
5. Into the Perimeter
6. Holding the Line
7. Back to the Parallel
8. On to the Border
9. Retreat to the South
10. The Second Six Months
11. Problems of a Policeman
12. Two More Years

A Note on Source Material

Glossary of Naval Abbreviations

• Part 1. The Korean Theater
• Part 2. 5-17 July: East Coast Bomdardment
• Part 3. 3-30 July: The Pohang Landing
• Part 4. 10-30 July: Seventh Fleet Operations 
• Part 5. 7 July-2 August: Patrol Planes and Gunnery Ships
• Part 6. 23 July-6 August: The Marines Arrive
• Source Notes

---

Part 1. The Korean Theater

          Although the conduct of war is always, in large measure, an exercise in applied geography, in Korea this was more than usually the case. On land, at sea, and in the air, the movements of forces and the employment of weapons were greatly affected by the nature of the arena.

          The Korean peninsula, divided by the fortunes of international politics, itself divides the Yellow Sea from the Sea of Japan. S-shaped, and with its long axis oriented generally north and south, the country lies between the parallels of 34° and 42° North, and spans the latitude between Los Angeles and central Oregon, or between North Carolina and the southern New Hampshire border. Although Korean territory extends for almost 600 miles from north to south, the distance between eastern and western coasts nowhere exceeds 200 miles, and in places is little more than half that distance. One consequence of this geographical configuration is of striking military importance: with a total area of some 83,000 square miles, or of 85,000 if all the islands are included, only a small strip along the northern border is more than 100 miles from the sea.

          But although Korea is surrounded by sea, its situation to leeward of the greatest of continents has given it a climate of extremes. While summer in the north is temperate the mountain winter is extremely bitter: even on the seacoast the mean January temperature at the Russian border is but 15 Fahrenheit. In southern Korea, by contrast, the climate is warm enough to permit the growing of cotton; summer temperatures reach the nineties, and the rains of June and July produce an exhausting combination of heat and humidity; at the peninsula's southwestern tip winters are frost-free and the August mean is 80°. Summer is also the season of typhoons, which form in the Marianas and move northwestward toward the East China Sea. Typically, they recurve in time to pass over southern Japan or through the Straits of Tsushima, with only their fringes affecting southeastern Korea; sometimes, however, they recurve late and cross the peninsula; always their approach brings problems for the navigator and the strategist.

Map 3. The Korean Theater Click on map for higher resolution image (187 KB).

          For five years prior to the outbreak of war the 38th parallel had divided Korea into roughly equal parts. But the division was an illogical one, resulting in such oddities as the isolation of the Ongjin peninsula in the west, and the separation of the city of Haeju from its port facilities; still more important was its separation of the populous and agricultural south from the complementary industrial economy of the north. Yet the parallel was not the country’s sole internal barrier, for long before geographers drew lines on maps, nature had divided this peninsula and subdivided it again.

          Much of Korea is mountainous. In all the peninsula there are no true flatlands or plains. Like Italy with its Alps, Korea is protected from the continental land mass to the north by high mountains which fill the triangular area above the mouth of the Yalu River, and extend beyond the border to the Manchurian plain. Much of this triangle lies above 3,000 feet; peaks of over 6,000 feet are not uncommon; only along the coast does the altitude drop below 1,500 feet. The Yalu and Tumen Rivers, which separate Korea from Manchuria and from the Russian Maritime Provinces, have their origins in the Pai Shan range, which towers above 9,000 feet and is capped by perpetual snow.

          Only three significant routes of access to the peninsula penetrate this formidable terrain. Of these the most important is the western corridor, along the lower reaches of the Yalu, through which the Japanese advanced in 1905 against the Russians and through which Communist Chinese forces would move against the United Nations. But there is also a gap in the mountains in central North Korea, formed by the valleys of the Tongno and Chongchon Rivers, while in the extreme northeastern corner of the country narrow valleys and a coastal strip lead down from eastern Manchuria and the Vladivostok region.

          From the northern mountain mass a rocky cordillera runs southward, paralleling the eastern coast; along this shore, except in the embrasure at the head of the Korean Gulf between the seaport cities of Wonsan and Hungnam, the mountains descend steeply to the sea. North of Wonsan the coast is somewhat indented, with a number of harbors and towns; to the southward it is almost unbroken and the Korean divide, running within ten miles of the Sea of Japan, hems in a narrow and isolated ribbon of land where population is sparse, towns are small, and ports are few. Behind the coastal range the mountain spine recurves to.the southwest, diminishes for a time in altitude, and then rises again in the south central region to form an isolated massif with peaks of five and six thousand feet. From the axial range, throughout the length of the peninsula, razorbacked spurs run off to west and southwest, compartmenting the country.

          These mountain spurs and isolated masses divide the populous western part of Korea into a series of river basins, draining into the Yellow Sea and the Korean Strait, which in earlier times formed the principal geographic and economic units of the country. Although not navigable by ocean-going ships, these rivers remain of considerable internal importance: the principal Korean ports lie at their mouths, and the capitals of North and South Korea only a short way upstream. Five of these rivers, two north and three south of the 38th parallel, deserve the attention of the student of the Korean War.

          The Chongchon River, northernmost of the strategically important west coast streams, is blocked to ocean shipping by drying mud banks which extend far offshore. But the central rail and road route to the north runs down its valley; the town of Sinanju, near the river’s mouth, is important as the junction of the western and central routes from Manchuria; and the bridges across the river are vulnerable to air attack.

          Sixty miles to the southward the Taedong River, scene of the massacre of the crew of the General Sherman, empties into the Yellow Sea. Near its mouth lies Chinnampo, a city of some 90,000, seaport of the important northern mining and industrial region. Fifteen miles upstream the city of Kyomipo contains Korea’s largest iron and steel works; 30 miles to the northeastward lies the North Korean capital of Pyongyang. Once the ancient capital of the country, Pyongyang contains the tombs of long-dead monarchs, including that of Kija, legendary inventor of the topknot. In the Sino-Japanese War it was the scene of considerable fighting; early in the century it became the last abode of the deposed emperor. Under the Japanese it developed into a considerable manufacturing city, with industry based on the neighboring coal mines, and in due course, as the largest city in the north, became the capital of the People’s Republic. Like the bridges over the Chongchon at Sinanju, those which cross the Taedong at Pyongyang are of strategic significance.

          Most important of Korea’s rivers is the Han, whose basin extends 150 miles from north to south and half that distance from east to west. With its principal tributaries, the Imjin and the Pukhan, the Han drains a major portion of the country on both sides of the 38th parallel. Rising only a few miles from the east coast, these streams wind through the central mountains before joining to pass the capital of Seoul and empty into the Yellow Sea near the principal west coast port of Inchon. For some 60 miles above its estuary the lower Han runs in a more or less east-west line, cutting the western lowlands and forming a potentially important and defensible military position.

          South of the Han basin and west of the coastal range the country is drained by two important rivers. Some 90 miles below Inchon the Kum descends from the central massif to empty into the Yellow Sea; at its mouth lies Kunsan, a principal shipping center for the agricultural regions of southwestern Korea. In the southeastern corner of the peninsula, between the coastal range and the central highlands, the Naktong River flows southward for 100 miles or so, then east, then south again to empty into the Korean Strait. Near the mouth of the Naktong is the excellent harbor of Pusan, second city of the country and port of ingress from Japan. To the north the Naktong basin is divided from that of the Han by mountains more than 3,000 feet high; on the west it is separated from the Kum by the southern massif. Between these mountain masses the divide between the Naktong basin and those of the Han and Kum diminishes in altitude; through this gap runs the main line of Korean communications, linking Japan and Pusan with the areas of heaviest population and agricultural production and with the capital at Seoul.

          The geography of Korea, in sum, is dominated by three main features: a north blocked by high mountains; an east coast strip isolated by the mountain spine; and a broken piedmont to the west and south divided into a series of river basins. Upon this pattern industrial man, in the person of the Japanese, imposed his own geography. But although railroads, like faith, can sometimes move mountains, in Korea this movement was only a partial one. A traffic pattern could be developed which would unite the river basins, but the linking of eastern and western provinces remained incomplete. The mountain framework, broken, jumbled, and forbidding, continued to dominate the life of the country and to impose a north-south orientation which made division at the 38th parallel the more painful.

          The first Korean railroad, built early in the century by the Japanese, linked the port of Pusan with the capital at Seoul. Although its construction required 99 bridges and 22 tunnels, it was completed by the time of the Russo-Japanese War. During that war its northward extension, from Seoul to Sinuiju on the Yalu River, was rushed to completion for strategic purposes. But a decade elapsed before the coasts were linked by a line through the mountain gaps between Seoul and Wonsan, and still longer until the construction of the east coast railroad, leading south from Siberia, began the transformation of fishing villages into industrial towns.

          By 1950 the main structure of rail and road communications had assumed an X-shaped pattern, with the crossing at Seoul. From Manchuria in the northwest a line of double track spanned the Yalu at Sinuiju and ran southeast to Sinanju. There it was joined by a line which crossed the border below the Suiho reservoir, and by one coming from the upper reaches of the Yalu by way of the Tongno-Chongchon gap. From Sinanju, where these lines merged, the double track ran south to Pyongyang, Seoul, and beyond. On the far side of the mountain masses, widely separated from this west coast network, another rail line came south from the Vladivostok complex. One coastal spur extended from the lower Tumen River to Najin near the Russian border; farther inland, the main line ran south to Chongjin, along the shore to the new manufacturing cities of Hungnam and Wonsan, and on through the mountains to Seoul. On the east coast south of Wonsan the track extended as far as Yangyang, just above the 38th parallel, but from Yangyang to Pohang, 65 miles above Pusan, movement depended on road and sea.

          The routes from the north thus converged at the Korean capital. Below this hub the railroad lines spread out again through South Korea. Two ran southeastward to the Pusan area, one leading directly from the valley of the Han into that of the Naktong, while the main line, now doubletracked, passed westward through Taejon in the Kum basin. From the latter, branches extended to the southwestern ports of Kunsan, Mokpo, and Yosu, but there was no south coast line, and rail traffic between Pusan and the southwestern ports had to be detoured northward around the central mountain massif.

          To this extent the mountains remained unconquered. The lack of lateral communication remained the dominant feature of the transportation nets, road and rail alike. Of intercoastal rail links there were but two, one running north and south between Seoul and Wonsan, and one east and west, connecting the Wonsan-Hungnam region to Sinanju and Pyongyang. The Korean transport system thus rested upon three focal points, the Wonsan area on the east coast, the Pyongyang-Sinanju complex on the west, and Seoul. This situation sufficiently explains the strategic importance of these regions, for while the Korean road net was much more extensive than that of the railroad, and permitted access to most of the mountain regions, the roads were generally poor, unimproved, and unsuited to heavy mechanized equipment, and the anatomy of the highway system followed that of the rail lines.

          Inevitably the scheme of maneuver adopted by the North Korean army for the conquest of this corrugated country was governed by the orientation of transport routes. The war had begun with a four-pronged invasion. The principal attack, delivered by the North Korean 3rd and 4th Infantry Divisions and the 105th Armored Brigade, and with two more divisions in reserve, was aimed south toward Seoul along the valley line from Wonsan. To the west the North Korean 6th Division overran the isolated Ongjin peninsula, and then joined with the 1st Division to move southeast, along the main line from Pyongyang, through Kaesong to the capital. In the central mountains the 2nd and the newly organized 7th Divisions attacked southward to Chunchon, terminus of a branch rail line from Seoul, after which the 2nd Division moved southwesterly down the railroad toward the capital while the 7th marched southward over mountain roads toward Wonju and the eastern of the two rail lines to Pusan. On the east coast beyond the divide, in a theater all its own, the North Korean 5th Division advanced southward along the shore road, leapfrogging ahead with small-scale amphibious operations.

          Four prongs became three as the mass of the invading troops converged upon the capital’s transportation nexus. In this second phase the 5th Division continued its independent operations east of the mountain spine, while in the central mountains the 7th Division, supported by constabulary troops, threaded its way southward through Wonju in the direction of Andong. But the overwhelming bulk of the North Korean army, five first-line infantry divisions, two divisions of recent conscripts, and the armored brigadle, had to be funneled through the Seoul complex. Once through the capital three divisions were peeled off to the southeast, and sent by rail and road to Wonju and Chungju to join the troops coming south through the mountains, while the remaining five moved down the main road. It was the advance guard of this massive force that Task Force Smith had run up against on 5 July.

          By the end of the second week of war the American 24th Division had been driven out of Chonan and was retiring on Taejon. Somewhat surprisingly, despite its overwhelming numerical strength, the North Korean army now slowed its advance: a full week was to pass before the battle of Taejon began. Although not apparently appreciated at the time, this was the first evidence of the logistic limitations which forced the enemy to conduct his offensives in a series of massive lunges, and which prevented the maintenance of continuous pressure during an advance. Only on 20 July, after a bitter three day fight in which General Dean, the division commander, was captured, was Taejon lost and the 24th Division forced once again to retreat.

          By this time the invasion was again a four-pronged affair. Unknown to the Americans, the North Korean army had split its main force a second time, and had sent the 6th Division with attached troops southward to Kunsan, which it entered on the 16th, and toward the southwestern tip of the peninsula. In pursuit of the retiring 24th Division the enemy main body, now seven divisions strong, pressed southeastward from Taejon along the main road and rail line toward the saddle which gives access to the Naktong Basin. Five dlivisions were moving through the mountains to the Andong area, while on the east coast the 5th Division continued its solitary southward course.

          Although this east coast threat was opposed only by the ROK 3rd Division, it was accessible to bombardment from the sea. ROK forces were also operating on the northern mountain front in the Andong-Chungju area, and the U.S. 25th Division was moving up from Pusan to Hamehang, north of Taegu, to block this enemy advance. It was the plan of General Walker, who assumed command of all ground forces in Korea on 13 July, to employ the 1st Cavalry Division to reinforce the 24th I)ivision on the main enemy route of advance, and to push the 29th Infantry, which was coming from Okinawa, west from Pusan to a blocking position south of the central hill mass. But by mid-July North Korean forces had covered more than half the distance to Pusan, and had occupied the line Chonju-Taejon-Yongjin-Yongdok, while the 1st Cavalry and the 29th Infantry had not yet arrived.

          As Korean physiography and the Korean transportation net governed the land scheme of maneuver, so the hydrography of the area profoundly affected naval capabilities. The Korean coastline, generally straight along the Sea of Japan but deeply convoluted on south and west, has a length of some 5,400 miles. The steepness of the east coast, where the mountains rising from the sea confine road and railroad to a narrow coastal strip, has its underwater counterpart: except in the Gulf of Korea, off Wonsan and Hungnam, the 100-fathom curve runs close to shore, coastal shipping is exposed, and warships can get within gun range of land communication facilities. But in the south and west conditions are very different, and the countless islands and deeply indented bays which mark the disappearance of the mountain ranges into the sea provide shelter for coastal traffic. The operations of major fighting ships are restricted, and effective supervision of coastal shipping calls for small craft of shallow draft. On the western shore further complications arise from the extraordinary hydrographic conditions of the Yellow Sea: whereas the tidal range in the Sea of Japan is of the order of a foot or two, here it ranges from 20 to 36 feet; currents are considerable and the water turbid; nowhere are there depths greater than 60 fathoms, and the 20-fathom line runs ten miles offshore. Extending far from land and exposed at low tide, the mud banks which trapped the French frigates a century ago remain a hazard for the unwary.

          These hydrographic facts of life and the very limited forces available combined to dictate the early activities of the Navy. Task Force 77 had been withdrawn to Okinawa, and the period from 5 to 17 July saw naval effort concentrated on the movement of troops and supplies into Pusan, gunfire support of ROK forces resisting the enemy east coast advance, and the planning of future operations.