Following the breakdown of armistice negotiations in August 1951, the United Nations Command (UN) decided to launch a limited offensive in the late summer/early autumn to shorten and straighten sections of their lines, acquire better defensive terrain, and deny the enemy key vantage points from which they could observe and target UN positions.

The armistice negotiations broke down in August, and the US Eighth Army commander, General James Van Fleet decided to launch a limited offensive to shorten and straighten sections of the lines, acquire better defensive terrain, and deny the enemy key vantage points from which they could observe and target UN positions and coerce the Chinese and North Koreans back to the negotiating table.

[2] In late August, three regiments of the US 1st Marine Division were given orders to move from their reserve areas around Inje County to support the UN offensive[1]: 44  and distract PVA and Korean People's Army (KPA) reinforcements from the Battle of Bloody Ridge.

[1]: 44  On 30 August, in preparation for the attack, a battalion of 1st Korean Marine Corps Regiment (1st KMC) occupied Hill 793 (38°17′24″N 128°10′12″E / 38.29000°N 128.17000°E / 38.29000; 128.17000) on the eastern edge of the Punchbowl between the Kansas Line and Yoke Ridge.

[1]: 61 At 06:00 on 31 August, the 7th Marine Regiment and two battalions of the 1st KMC launched the assault with an attack from Hill 793 up the eastern edge of the Punchbowl towards Yoke Ridge in the west and Tonpyong in the east.

[1]: 59  By late morning, despite heavy rain and enemy minefields, the assault units had reached Yoke Ridge and were engaging the KPA defenders.

The KPA launched several small-scale counterattacks against the advancing Marines, but these were broken up by small-arms and mortar fire, artillery and several airstrikes.

[1]: 101–110  1st Battalion 7th Marines were tasked with capturing Hill 673, but strong opposition from the well-protected KPA bunkers forced them to stop short of their objective.

[1]: 113–6  Sergeant Frederick W. Mausert III was posthumously awarded the Medal of Honor for his actions during the assault on Hill 673.

[1]: 131  Hill 749 proved to be a heavily defended fortress of bunkers, covered trenches and tunnels and part of the KPA main line of resistance.

[1]: 149–50  During this assault, Private First Class Edward Gomez smothered a KPA hand grenade with his body, saving the lives of the rest of his machine-gun team, for which he was posthumously awarded the Medal of Honor.

[1]: 158  Delayed preparatory fire, limited air support, and a tenacious KPA defense meant that 2/1 Marines were unable to make any appreciable gains by nightfall and had to withdraw to their previous positions, having suffered 70 wounded.

[1]: 162–5  Corporal Joseph Vittori was posthumously awarded the Medal of Honor for his actions in countering the KPA assault.

A dawn artillery barrage on Hills 812, 980 and 1052 inflicted significant casualties on the KPA defenders, who were eating meals in the open.

[1]: 218  The previous day, General Van Fleet had visited the 1st Marine Division Command Post and then ordered X Corps to suspend all major operations after 20 September, as further attacks along the Hays Line could no longer be justified,[1]: 222  and he wished to concentrate all of X Corps' fire support to conclude the Battle of Heartbreak Ridge.

1st Marines were ordered to assist the 8th ROK, but the attack did not begin until 17:30 and quickly bogged down in the face of well-defended KPA bunkers.

[1]: 235–250 The UN offensive in the Punchbowl area concluded on 21 September, however the KPA continued to probe the UN lines and direct fire on their positions.

[1]: 300–1  The failure to press on and capture Hills 980 and 1052 was viewed by many Marines as a tactical error as those heights overlooked the UN lines and numerous casualties resulted in the stalemate period that followed.