The last two years of the war in Korea resembled the trench warfare of the western front in World War 1...
A war of rapid movement was replaced by one of night patrols in no-mans-land and set-piece offensives launched from trenches across enemy minefields and barbed wire with massive artillery support. Like WWI and WWII the war on land became an artillery war – artillery inflicted most of the casualties and without its support there was no prospect of storming the strong trench systems both sides constructed.
While neither the United Nations Command (UNC) nor the communists now aspired to total victory, there was still a point in seizing vital ground to influence the ceasefire negotiations which began in July 1952. The communists reasoned UNC democracies were susceptible to political pressure from home to make concessions at the negotiations if the UNC was seen to suffer repeated battlefield defeats or high casualties. It was also possible no ceasefire would occur, so improving the defensive lines made military sense. Typically, battles of 1952 and 1953 were small but intense, designed to seize a high point of the enemy line which gave observation into the enemy rear area. Heartbreak Ridge, Pork Chop Hill and The Hook, where 2nd Battalion Royal Australian Regiment fought, were examples of the kind of war waged.
If either side had decided to try it, a major breakthrough would have been unlikely because of the increasing size of the armies. By the start of 1953 the 200 kilometre front line was held by nearly a million men on each side. With an average of almost 5000 per kilometre of front, the prospect of a breakthrough was small.
As the more manoeuvrable army, well supplied with vehicles and able to transport troops by sea and air, the UNC was better placed in the mobile war of the first year in Korea. Now the stability of the front lines gave the communist forces some advantages. Over months they were able to build up huge reserves of ammunition for their artillery, and mass their troops without revealing where along the line they planned to strike.
The UNC retained the great bonus of control of the sea and the air by which means it could rapidly transfer firepower to wherever it was needed. By 1952 the UNC maintained at last three aircraft carriers at sea at any one time, including HMAS Sydney. In the air the UNC had 640 combat aircraft including the Meteors of 77 Squadron, Royal Australian Air Force. These controlled the skies over all but the far north of Korea, known as MiG alley, where the Soviet-supplied and partly Soviet-manned Chinese air force held air superiority.