The 28th British Commonwealth Brigade was part of a four-division attack — Operation COMMANDO —just north of the 38th parallel. 3 RAR’s contribution was to assist in the capture of Hill 355 (Kowang San) by a British unit and, in the second phase of the battle, take Hill 317 (Maryang San) itself. The Americans had tried to capture Maryang San and failed on two previous occasions. Maryang San was mountainous and rugged, with opportunities for both entrenched defence and attackers to move under cover of foliage.
The assault against Kowang San was launched on 3 October 1951. Well-entrenched Chinese positions caused heavy casualties among the United Nations allies. With the final capture of this first hill (Kowang San) delayed until late on 4 October, 3 RAR’s Commanding Officer, Lieutenant Colonel Frank Hassett, launched his attack against the eastern ridge of Maryang San at 4.45 am on 5 October, having first positioned his companies in the foothills of the objective under cover of darkness.
With A Company creating a diversion on the south-eastern spur, B Company made its way up to the crest of the eastern ridge, allowing D Company to fight on to take the objective. C Company remained in reserve. Under cover of mist from the Imjin River, progress was reasonably solid until late morning when the mist lifted. Suddenly exposed halfway up the steep hillside of the main ridge, D Company pushed through a severe firefight to take one of Maryang San’s knolls, leaving further heavily defended knolls still to capture.
D Company continued on with the support of 3 RAR’s Medium Machine Gun Platoon, taking a further two knolls under heavy grenade, small arms and machine-gun fire, but counting on accurate supporting mortar and artillery fire to suppress the defenders as much as possible. At this point, Hassett threw C Company in to support D Company and make a final push for the summit of Maryang San. A Company was absorbing heavy Chinese fire on the southern flank allowing D Company (and C Company) to progress along the knolls without additional defenders to negotiate. C Company climbed the remaining 130 metres up the steep slope and removed the Chinese from the summit at 5 pm. Thereafter they resisted heavy counterattacks, while A Company cleared the Chinese from their positions south-east. The summit had to be defended for a further two days against shelling and mortar fire.
Having secured Maryang San, Hassett was directed to assault ‘The Hinge’ to assist the attack by the Northumberland Fusiliers on Hill 217. B Company attacked along the ridge from Maryang San towards ‘The Hinge’ with Hassett coordinating supporting fire from his headquarters on the summit of Maryang San, which was also subject to fierce bombardment. B Company took ‘The Hinge’ on the morning of 7 October and continued to hold it through what Captain A.G.W. Keys described as ‘the Communists’ biggest artillery effort of the war’.
Three separate Chinese counterattacks failed to budge the Australians from their position and, by dawn on 8 October, the Chinese had abandoned their assault on ‘The Hinge’ and withdrawn from Hill 217. The objectives had been won. In five days of fighting, 3 RAR had destroyed two Chinese battalions, killed at least 283 Chinese, and taken 50 prisoners, with a loss of 29 killed and 89 wounded in action.