Editing Battle of Chosin Reservoir (section)

===Actions at Yudam-ni===
[[File:Chinese 79th Division at Chosin.jpg|thumb|alt=A group of soldiers climbing up a snow-covered hill|Soldiers from the Chinese 79th Division moving to engage the Marines at Yudam-ni]]
Acting on Almond's order, Smith ordered the 5th Marines to attack west toward Mupyong-ni on 27 November.{{sfn|Appleman|1990|p=52}} The attack was soon stalled by the PVA 89th Division and forced the Marines to dig in on the ridges surrounding Yudam-ni.{{sfn|Roe|2000|p=301}}{{sfn|Appleman|1990|p=56}} As night came, three Chinese regiments of the 79th Division attacked the ridges on the north and northwest of Yudam-ni, hoping to annihilate the garrison in one stroke.{{sfn|Guang|2007|p=68}} Close quarters fighting soon developed as the attackers infiltrated Marine positions,{{sfn|Appleman|1990|pp=64–68}} but the 5th and 7th Marines held the line while inflicting heavy casualties on the Chinese.{{sfn|Guang|2007|pp=68–71}}{{sfn|Appleman|1990|p=74}} As day broke on 28 November, the Chinese and Americans were locked in a stalemate around the Yudam-ni perimeter.{{sfn|Guang|2007|p=71}}

While the battle was underway at Yudam-ni, the PVA 59th Division blocked the road between Yudam-ni and Hagaru-ri by attacking the defending Charlie and Fox Companies of the 7th Marines.{{sfn|Appleman|1990|p=227}} The successful assault forced Charlie Company to retreat into Yudam-ni, which left Fox Company, commanded by Captain [[William E. Barber]], isolated on a hill overlooking the Toktong Pass, a vital pass that controlled the road.{{sfn|Appleman|1990|p=73}} On 29 November, several efforts by the 7th Marines failed to rescue Fox Company, despite inflicting heavy casualties on the Chinese.{{sfn|Appleman|1990|p=178}} Aided by artillery from Hagaru-ri and Marine [[F4U Corsair|Corsair fighters]], Fox Company managed to hold out for five days while enduring constant attacks by the PVA 59th Division.{{sfn|Appleman|1990|p=226}}

After the heavy losses suffered by the PVA 79th Division at Yudam-ni, 9th Corps headquarter realized that the bulk of the 1st Marine Division was stationed at Yudam-ni, with a garrison strength double the initial estimate.{{sfn|Roe|2000|p=329}} Believing that any further assaults would be futile, Song Shilun ordered the 9th Corps to switch their main attacks toward Sinhung-ni and Hagaru-ri,{{sfn|Roe|2000|p=329}} leaving Yudam-ni alone from 28 to 30 November.{{sfn|Appleman|1990|p=213}} At the same time, the US Eighth Army on the Korean western front was forced into full retreat at the [[Battle of the Ch'ongch'on River]], and MacArthur ordered Almond to withdraw the US X&nbsp;Corps to the port of Hungnam.{{sfn|Appleman|1990|pp=120–121}} Acting on Almond and Smith's instructions, Lieutenant Colonel [[Raymond L. Murray]] and Colonel [[Homer Litzenberg|Homer L. Litzenberg]], commanders of the 5th and 7th Marines, respectively, issued a joint order to break out from Yudam-ni to Hagaru-ri on 30 November.{{sfn|Appleman|1990|p=215}} Faced with tough fighting between the blocking Chinese divisions and the withdrawing Marines, Smith remarked: "Retreat, hell! We're not retreating, we're just advancing in a different direction."{{sfn|Retreat of the 20,000 |1950}}

For the breakout, the Marines formed into a convoy with a single [[M4 Sherman|M4A3 Sherman tank]] in the lead. The plan was to have [[3rd Battalion 5th Marines|3rd Battalion, 5th Marines]] (3/5) as the vanguard of the convoy, with three battalions covering the rear. At the same time, [[1st Battalion 7th Marines|1st Battalion, 7th Marines]] (1/7) would attack towards Fox Company in order to open the road at Toktong Pass.{{sfn|Appleman|1990|pp=215–216}} To start the breakout, [[3rd Battalion 7th Marines|3rd Battalion, 7th Marines]] (3/7) had to first attack south and capture Hills 1542 and 1419 in order to cover the road from Chinese attacks.{{sfn|Appleman|1990|p=218}} The breakout was carried out under the air cover of the 1st Marine Air Wing.{{sfn|Appleman|1990|p=214}}

[[File:Marines engage during the Korean War.jpg|thumb|left|alt=A line of soldiers on a hill engaged in a battle|Marines engaging the Chinese]]
On the morning of 1 December, 3/7 Marines engaged the PVA 175th Regiment of the 59th Division at Hills 1542 ({{Coord|40.435|N|127.107|E|display=inline}}) and 1419 ({{Coord|40.428|N|127.135|E|display=inline}}). The Chinese defenders soon forced the Marines to dig in on the slopes between the road and the peaks{{sfn|Appleman|1990|p=220}} when the convoy passed 3/7's position by the afternoon.{{sfn|Appleman|1990|p=218}} With Hagaru-ri still not captured, the PVA High Command scrambled the 79th Division to resume attacks on Yudam-ni, while the 89th Division rushed south towards Kot'o-ri.{{sfn|Guang|2007|p=88}} The Chinese struck at night, and the ferocity of the fighting forced the rear covering forces to call in [[night fighter]]s to suppress the attacks.{{sfn|Appleman|1990|p=223}} The fighting lasted well into the morning of 2 December until all the Marines had managed to withdraw from Yudam-ni.{{sfn|Appleman|1990|p=223}}

At the same time, 1/7 Marines also tried to break the Chinese blockade at Hill 1419 on 1 December. Despite being badly reduced by combat, hunger and frostbite, the PVA 59th Division sent in its last five platoons and refused to yield.{{sfn|Guang|2007|p=86}} As night approached, 1/7 finally captured the peak and started to march through the hills on the east side of the road.{{sfn|Appleman|1990|p=233}} Relying on the element of surprise, they managed to destroy several Chinese positions along the road.{{sfn|Appleman|1990|p=234}} On the morning of 2 December, a joint attack by Fox Company and 1/7 secured the Toktong Pass, thus opening the road between Yudam-ni and Hagaru-ri.{{sfn|Appleman|1990|p=235}}

Although the road had been opened between Yudam-ni and Hagaru-ri, the convoy still had to fight through the numerous Chinese positions on the hills overlooking the road. On the first night of the retreat, the Chinese struck the convoy in force and inflicted heavy casualties on 3/5 Marines.{{sfn|Appleman|1990|pp=221–223}} Although strong air cover suppressed most of the Chinese forces for the rest of the march, the cold weather, harassing fire, raiding parties, and roadblocks slowed the retreat to a crawl, while inflicting numerous casualties.{{sfn|Appleman|1990|pp=224–225}} Despite those difficulties, the convoy reached Hagaru-ri in an orderly fashion on the afternoon of 3 December, with the withdrawal completed on 4 December.{{sfn|Appleman|1990|pp=239–243}}