Greatest Battles
How did the Battle of Inchon change the course of the Korean War?
Even the main proponent only gave this desperate military gamble a one in 5,000 chance for success, but it turned the tide of a war that still shapes today’s world. The legacy of the Korean War (1950‑3) still stands as a stark feature on the global landscape, with the fluctuating relations between the Communist north (the Democratic People’s Republic of Korea – DPRK) and the democratic south (the Republic of Korea – ROK) having far-reaching repercussions across the world. The partition of Korea dates back to 1945 when the country was liberated from over 40 years of Japanese rule and was divided along the 38th Parallel. The Soviets had occupied the north, establishing a Communist government, while the USA had occupied the south and established a highly corrupt but at least nominally democratic rule. The state of affairs was recognised by the
United Nations in August 1948, and at the end of the
year the Soviets had withdrawn their occupation forces, leaving behind an established military and considerable amounts of hardware. The US forces withdrew in June 1949, leaving a small and poorly equipped ROK army.
For the North Koreans, it made sense to strike as soon as possible to ‘re-unite’ the country under their rule. The north was much larger – 48,000 square miles against the south’s 37,000 – but had a far smaller population – just 9 million against the south’s 21 million. However, the DPRK’S military at that time was the larger of the two, with 223,000 trained and experienced troops (albeit at insurgency and irregular warfare), large numbers of T‑34 tanks and over 100 former Soviet aircraft. The South’s army was a ramshackle 98,000 poorly trained troops with little heavy weaponry. The North seized its chance, and at 4am on 25 June 1950, its forces swept south.
The DPRK’S army shattered the Rok’s. On 3 July, Seoul, the capital of South Korea, fell to Northern forces. Only around 40 miles from the 38th Parallel, the city stood in the north-western corner of the country, and the remains of the South’s army began to stream towards Pusan (now known as Busan) in the south-eastern corner of the Korean peninsula.
The United Nations immediately moved to condemn the North’s actions and (due to the Soviets’ having walked out of Council meetings earlier) a resolution was passed to send forces to defend South Korea. Many countries would send troops and other resources to support the action, including British and Commonwealth forces, but the vast majority of the military muscle would be American, as would the senior commanders.
The US forces in the Far East were in a deplorable state, as were those in America itself. Only in Germany were full-strength divisions maintained, and elsewhere units from divisional level downwards were kept at well below their wartime strength. Training had also lapsed, with a focus on general education rather than weapons or tactical skills. The four divisions on occupation duties in Japan were quickly stripped to start making up full-strength units to throw into the fight; initially a single battalion (which was quickly overwhelmed) was sent and then a division, supported by further units, including a composite US Marine brigade and the British 27th Infantry Brigade. A fighting retreat developed that eventually led to a solid perimeter being formed around Pusan in the first week of August. With a front of 258 kilometres
(160 miles), held by around 45,000 United Nations and South Korean troops of the US 8th Army, the line finally held. The Communist forces, exhausted and scattered after their rapid advance south, could not break through.
The question for the UN forces was, what to do now? It was only a matter of time until their numerical and technological strength grew to the point where they could counter-attack, but how should they, and where? Breaking out of
Pusan could be hard work, and would lead to a 300-kilometre (200-mile) slog over mountainous terrain to liberate Seoul. Two elements immediately in their favour were air superiority and absolute control of the sea. The North’s tiny navy had been neutralised, leaving the UN master of the long, vulnerable Korean coastline. Already aircraft carriers and commando forces were striking against the North’s lines of communications.
Commander of the UN forces was General of the Army Douglas Macarthur, whose actions throughout an eventful career had made him a controversial figure. Strong-willed and opinionated, he held his military and (especially) political masters in contempt. He wanted to be bold and land deep behind enemy lines. He believed that only this would lead to swift re-conquest of the south: a landing to threaten the enemy’s rear and force them to pull forces back, allowing the forces in Pusan to break out. They would then become a hammer to smash the enemy on the anvil of the beachhead, wherever it was decided that would be.
Opinions varied as to where the ‘anvil’ should be landed. Macarthur dismissed most as being too close to Pusan, but became fixated on Inchon (now Incheon). It was in many ways a ridiculous choice. To reach it, a naval force would need to approach along a channel 13 kilometres (eight miles) long and only 1.6 kilometres (one mile) wide, and then land their forces on beaches where the tidal range was around 9.5 metres (31 feet). Expansive mudflats close to land meant that LCTS and other craft could only reach the shore at the very peak of highest monthly tides. Any landing would have to be made by one wave landing at the dawn high tide, and the next wave at the dusk one. The beaches were lined with high sea walls, and high ground overlooked the whole area. An isthmus ran 800 metres (half a mile) out into the sea, leading to a large island called Wolmi Do, with another smaller island, Sowolmi Do beyond it. These encircled most of the harbour area. Militarily, it seemed lunacy, and even Macarthur, who had to argue for the idea against not only his superiors but also most of his own subordinates, only gave it a one in 5,000 chance of success.
However, Macarthur was also a born selfpublicist, ever aware of his image and how it could be bolstered by his defeating such odds. In truth, he knew that the operation had several factors in its favour. The sheer unlikeliness of Inchon as a target, for all the above reasons, meant it was thinly defended. It was also only 16 kilometres (ten miles) from Kimpo (now known as Gimpo) Airfield, the largest and best airfield in the country, and as far again beyond that was Seoul. A fast seizure of the airfield would help his forces immensely, while the swift liberation of Seoul would be an incredible boost to morale.
With Inchon decided, Macarthur set about organising the landing – the first major seaborne operation since 1945. Much of the vast amphibious infrastructure that had won the Pacific campaign had been dismantled, but the experienced staff were still there. Landing craft were gathered (including ones sold to Japan as coastal shipping, to replace hulls sunk during the war), and a supporting fleet assembled. Troops were harder to find. The US Marine Corps (USMC) was being downsized almost out of existence, reduced to shipboard contingents instead of expeditionary forces. However, enough were gathered from the US and the forces already in Korea to form the 1st US Marine Division. As in the army, training had suffered, but (also as in the army) the senior NCO and officer ranks contained a core of experienced, battle-hardened men who began to whip their troops into shape. The US 7th Infantry Division was also gathered, and together the two divisions would form the US 10th Corps, under the command of a relatively inexperienced officer who was a protégé of Macarthur.
Over 250 ships and boats of all sizes (nearly all of them American) were gathered, and set course for Inchon. The US 1st Marine Division would make
“A fast seizure of Kimpo airfield would help Macarthur’s forces, while the swift liberation of morale” Seoul would be an incredible boost to
the initial landings, although one third of it (the 7th Regiment) was still en route, their place being taken by the 1st Korean Marine Corps Regiment. The 7th Division would follow (with the missing Marine regiment) a week behind. During the days before the landings, UN aircraft and ships attacked the defences at Inchon and elsewhere. After only a month’s preparation, the fleet entered the channel of Inchon.
At 5.45am on 15 September 1950, warships began to bombard the landing beaches and rear areas, while carrier-launched aircraft also joined the fray. The fire focused on the first objective – the island of Wolmi Do. At 6.30am, the morning high tide, 3rd Battalion 5th Marine Regiment (3/5th) landed on Beach Green, on the north-western corner of Wolmi Do near the isthmus to the mainland. Supported by ten tanks, they secured the island and Sowolmi Do by midday. Bombardments of the mainland continued while the fleet waited for the next high tide.
Towards 5pm the shelling intensified. Two Regimental Combat Teams (RCTS – three battalions totalling over 1,000 combat troops plus heavy weapons companies) prepared themselves. At 5.30pm the main landing was made. At Beach Red, on the shorefront of the town of Inchon itself, the
5th Marines RCT (less the 3/5th on Wolmi Do) had to use scaling landings to clamber from their landing craft up over the high sea wall. They advanced rapidly through the harbour and into the city streets, desperate to reach their objectives before dark. A line of high ground – Cemetery Hill, British Consulate
Hill and Observatory Hill – were stormed and taken against light resistance, and a line established just over a kilometre inland, about halfway through
Inchon town. Behind them, eight LCTS beached themselves, each carrying 500 tons of supplies to keep the Marines fighting until the next high tide.
Further south, on Beach Blue the 1st Marines
RCT landed on the far side of the salt pans and tidal basins, some four kilometres (three miles) from Beach Red. Smoke drifting south from fires in Inchon and a growing fog limited visibility, and units became mixed up both off-shore and after landing, but again resistance was light. Macarthur’s assessment that Inchon would be lightly guarded was correct, with only around 2,000 North Korean troops in the area. Their responses were ill-coordinated and easily dealt with piecemeal, and by dark the US Marines had established two solid, but separated, beachheads, while casualties had been remarkably light. The gamble had worked.
On the following day, the Marines continued their advance, linking their beachheads and pushing on towards Kimpo Airfield. Although garrisoned by around 3,000 troops from the DPRK 107th Security Regiment and 42nd Tank Regiment, resistance was again poorly co-ordinated. By the evening of 17 September Kimpo was secured, and two days later a USMC air group was operating from it. Communist resistance was still limited to local counter-attacks, and on 20 September the 1st Marine Division crossed the River Han, a major obstruction on the way to Seoul. With the US 7th Division and the 7th USMC RCT now landing and coming up into the line, the UN forces began to surround Seoul. DPRK forces amounted to an estimated 33‑35,000 troops in the area, but many of these were raw recruits, logistics troops or exhausted combat formations.
On 16 September, the UN forces at Pusan had begun their breakout, finally forcing the Communists into retreat on 22 September. With the hammer of the US 8th Army coming up from the south, the North Korean forces were surrounded and in disarray. On 25 September the attack on Seoul opened, and the following day the 8th Army linked up with 10th Corps. On 27 September, Seoul was officially liberated. The advance now began to push the North Koreans back across the 38th Parallel, which was achieved by the end of the month.
The South Korean forces then crossed the Parallel, sparking an intervention by China and setting the conditions that would lead to three years of bloody stalemate. Macarthur was sacked soon after for his cavalier attitude to the orders of his political masters, and his plans to escalate to nuclear warfare.
However, his plan for Inchon had been a masterstroke. A landing nearly 300km (200 miles) behind enemy lines on an unsuitable shore had succeeded, and been followed by a 32-kilometre (20mile) advance to liberate the ROK capital just three months after it had fallen. The operation had been planned and executed in rapid time with inadequate resources and no rehearsals. The US 10th Corps had suffered some 580 men killed or missing and around 2,400 wounded, but had killed 18,000 of the opponents and captured a further 6,000 while shattering the North Korean occupation of the South.