The Battle of the Samichon River (24–26 July 1953) was fought during the final days of the Korean War between United Nations (UN) forces—primarily Australian and American—and the Chinese People's Volunteer Army (PVA). The fighting took place on a key position on the Jamestown Line known as "the Hook", and resulted in the defending UN troops, including the 2nd Battalion, Royal Australian Regiment (2 RAR) from the 28th British Commonwealth Brigade and the US 7th Marine Regiment, repulsing numerous assaults by the PVA 137th Division during two concerted night attacks, inflicting numerous casualties on the PVA with heavy artillery and small-arms fire. The action was part of a larger, division-sized PVA attack against the US 1st Marine Division, with diversionary assaults mounted against the Australians. With the peace talks in Panmunjom reaching a conclusion, the Chinese had been eager to gain a last-minute victory over the UN forces, and the battle was the last of the war before the official signing of the Korean armistice.

During the action, the PVA attempted to make a breakthrough to the Imjin River along the divisional boundary between the US 1st Marine Division and the 1st Commonwealth Division to turn the 1st Marine Division's flank. Yet with well-coordinated indirect fire from the divisional artillery, including the 16th Field Regiment, Royal New Zealand Artillery, and support from British Centurion tanks of the 1st Royal Tank Regiment, 2 RAR successfully thwarted both assaults, holding the Hook. UN sources estimated PVA casualties at 2,000 to 3,000 killed, with the majority of them inflicted by the New Zealand gunners. Meanwhile, on the left flank, US Marines endured the brunt of the attack, repelling the PVA onslaught with infantry and artillery. Only a few hours later, the armistice agreement was signed, ultimately ending the war. Both sides subsequently withdrew within 72 hours to create the Korean Demilitarised Zone.

Background

Military situation

Following the Battle of Maryang San in early October 1951 the 28th British Commonwealth Brigade maintained a defensive posture for the rest of the month. Amid heavy fighting on the afternoon of 4 November the PVA recaptured Hill 317, which was by then held by the 1st Battalion, King's Own Scottish Borderers, in an action for which Private Bill Speakman was later awarded the Victoria Cross. The hill remained in PVA hands until the end of the war. The Battle of Maryang San subsequently proved to be one of the last UN actions in the war of manoeuvre, and with peace talks going on, the fighting was replaced by a static war characterised by fixed defences, trench lines, bunkers, patrols, wiring parties, and minefields reminiscent of the Western Front of 1915–1917. Construction of defensive localities sited in all-round defence with interlocking arcs of fire began almost immediately, although such operations were confined to the reverse slopes during the day due to artillery and mortar fire. Patrolling and ambushing by both sides also began to prevent the other from gaining control of no man's land. The 1st Commonwealth Division, which included British, Australian, Canadian, New Zealand, and Indian troops, subsequently occupied part of the Jamestown Line—a UN defensive position that extended across central Korea—in the US I Corps' sector on the US Eighth Army's left flank. The war was no less bloody, though, and the division remained in the line for all but two of the remaining 19 months of the war.

From 19 January 1952, the 3rd Battalion, Royal Australian Regiment, (3 RAR) was in defence on the Jamestown Line as part of the 28th British Commonwealth Brigade before going into reserve on 18 April, where they remained until the end of June. Meanwhile, in early 1952, the Australian government had agreed to an American request to increase its forces in Korea, dispatching a second infantry battalion to join 3 RAR which had been fighting since September 1950. The 1st Battalion, Royal Australian Regiment, (1 RAR) arrived in Korea on 6 April 1952, with both battalions forming part of the 28th British Commonwealth Brigade under the command of an Australian brigadier. The brigade re-entered the line on 30 June and 1 RAR spent the following fourteen weeks patrolling, ambushing and raiding, before the 28th British Commonwealth Brigade again went into reserve on 5 October. The brigade returned to the Jamestown Line in early November, with 1 RAR taking over the defences on Hill 355 from the Canadians. The Australians were subsequently forced to clean up large quantities of rubbish left by the Canadians as well as repairing and camouflaging the defences which had recently been attacked by the PVA. 1 RAR implemented an aggressive patrol program in an effort to regain control of no-man's land from the PVA, which had been allowed to establish hides close to the perimeter. Several PVA outposts were subsequently destroyed during raids of up to company-size.

On 28 December 1952, 3 RAR took over the defences on Hill 355 and remained there until the 1st Commonwealth Division went into reserve at the end of January 1953. On 21 March, 1 RAR was replaced in Korea by 2 RAR, after nearly 12 months of operational service. Heavy fighting occurred in March, with the PVA moving back over to a limited offensive in the US I Corps' sector, in an attempt to regain the initiative following the winter. Heavy fighting occurred around the Hook, which was by then held by the US 2nd Infantry Division following the relief of the 1st Commonwealth Division, the Old Baldy and Pork Chop Hill features held by the US 7th Division, and in the western sector held by the US 1st Marine Division around the Vegas and Nevada Complex. Peace talks finally resumed at Panmunjom on 6 April and an agreement was soon made to exchange sick and wounded prisoners. Consequently, 648 UN and 6,670 PVA and North Korean prisoners were repatriated as part of Operation Little Switch on 20 April, including five Australians. For a while, the tempo of operations slackened, returning to the small-scale raids and probes of the winter months. Yet during the final three months of the war, the PVA launched a series of offensives prior to the signing of a ceasefire agreement.

In early April 1953, the 1st Commonwealth Division returned to the Jamestown Line. By this time, the division was commanded by Major General Michael West, a British officer who had taken over command in September the previous year. The 28th British Commonwealth Brigade subsequently occupied the north-eastern sector. Hill 159 was occupied by 2 RAR during 5 May to 16 June, while 3 RAR held Hill 355 during the period 7–27 May; 3 RAR then relieved 2 RAR on 16 June and remained on Hill 159 until 10 July. Meanwhile, the Hook was a key position on the left flank of the line held by the 1st Commonwealth Division and was the division's most threatened sector on the Jamestown Line. Held by the 29th British Infantry Brigade, the position consisted of a group of hills west of the Samichon River which dominated the Imjin River, to the south, and provided observation and fields of fire over a bend in the river as it turned towards Seoul. Loss of the Hook would force the UN troops to withdraw nearly to the next tenable defensive line on the high ground south of the Imjin River. As a result, the PVA had made repeated attacks against it, with the 1st Battalion, Princess Patricia's Canadian Light Infantry, repulsing the first PVA attempt in late-March 1952. the 1st Marine Division defended the area in the First Battle of the Hook in October 1952. The 1st Battalion, the Black Watch, did so again in November 1952, while the 1st Battalion, Duke of Wellington's Regiment, had fought the heaviest battle there in May 1953 during the Third Battle of the Hook.

In the western sector, American outposts such as Detroit, Berlin, East Berlin, Reno, Carson, Elko, and Vegas had been bitterly contested over the previous months by the US 1st Marine Division and the Turkish Brigade, but by June, the Reno, Elko, and Vegas positions were held by the PVA. The front subsequently returned to its usual defensive routine, but following a temporary break-down in negotiations after the unilateral release of 25,000 anti-communist Chinese and North Korean prisoners of war by President of South Korea Syngman Rhee, the PVA had renewed large-scale attacks on 24 June. Concentrating on the Republic of Korea Army (ROK) divisions in the eastern and central sectors, the PVA launched another offensive in June in an attempt to convince the South Korean leader to come to terms. The fighting continued until the end of the month, as the PVA successively drove back elements of ROK 9th Division in the US IX Corps sector and the ROK 1st Division in the US I Corps sector.

By early July, the PVA launched a major offensive in the ROK II Corps and US X Corps sectors. The Americans and ROK subsequently responded with a series of counter-attacks to regain the ground lost, yet these met with only limited success. On 6 July, the PVA attacked elements of the US 7th Division on Pork Chop Hill on the US I Corps' right flank, and succeeded in gaining the crest. The Americans were reinforced and counter-attacked over the following days, although again without success. Following another PVA assault on 9 July, the Americans again counter-attacked, yet neither side gained a clear advantage. The following day, the PVA launched a series of company- and battalion-sized assaults, but were repulsed. With the Americans unprepared to accept further casualties for limited tactical gain, though, they evacuated Pork Chop Hill on 11 July.

Prelude

The peace talks resumed in early July as Rhee's position apparently softened, yet this proved to be the impetus for a final PVA offensive, as they sought to further influence the talks and improve their defensive positions at the same time. On 14 July, elements of five PVA armies struck six South Korean divisions around the Kumsong salient. By 20 July, the ROK Capital Division and much of the ROK 3rd Division had been practically destroyed, exposing serious weaknesses despite two years of American training. The ROK fell back and the UN line was penetrated to a depth of . Only American intervention restored the situation, and ultimately, nine ROK and US divisions were required to stem the PVA offensive and regain some of the lost ground. Following a counter-attack by ROK II Corps, a new defensive line was established south of the Kumsong River. Meanwhile, in conjunction with the main offensive at Kumsong, the PVA 19th Army Group had conducted a series of limited offensives against US I Corps, with the 46th Army conducting assaulting 1st Marine Division outposts from 7 to 27 July. PVA losses were heavy nonetheless, and they sustained more than 28,000 casualties for only temporary gain.