On November 2, other units of the 8th Cavalry Regiment, which had managed to elude the Chinese ambush, retreated southward along the narrow, winding mountain road from Unsan. As their vehicles trudged along a track made more for pedestrians and donkeys, they ran into ambushes set up by People's Volunteers. The latter fired all their automatic weapons and a shower of hand grenades fell on the road which was soon strewn with bodies and equipment.
The battle of Unsan cost nearly the half of his men in the 8th Cavalry Regiment, 12 105 howitzers, 9 tanks, some 125 trucks and 12 recoilless guns. After many more brief but equally fierce engagements, on November 7 the Chinese Communists broke the American and South Korean positions. The United Nations forces fell back and crossed the Chongchon River.
General MacArthur, along with his men, now recognized the presence of a Chinese threat in Korea, but he did not yet fully appreciate its significance. He thought it was just an armed demonstration by the Chinese to bolster the morale of the North Koreans. reconnaissance north of the Yalu prevented MacArthur from fully appreciating the situation. In any case, by the time he got permission to bomb the Yalu bridges, the bulk of the Chinese troops had already entered Korea. Later, MacArthur referring with humor to this forbidden region, spoke of the "Sanctuary of Manchuria". of the real power of the Chinese. Whether this ignorance was the result of the "Sanctuary" policy followed by MacArthur's superiors, the inefficiency of the U.N. or serious errors in judgment and interpretation by MacArthur himself. The United Nations forces, who had the same fragmentary view of the situation as their commander-in-chief, regarded the November offensive as the last major action intended to assure them victory, and the return to their country before Christmas.
During the attack, MacArthur had planned that the Eighth Army, under Lieutenant-General Walton Walker, would advance in a broad front from the Chongchon River north- west:it included 4 American divisions, 4 South Koreans, the 27th brigade of the British Commonwealth and the Turkish brigade. At the same time, 120 kilometers to the east, the 10th corps, strong of 3 American divisions, 2 Korean divisions as well as British Marine commandos and other units, would march northeast then turn left to join the Eighth Army.
Events and forecasts could hardly have diverged more.
On the night of November 25 to 26, U.N. advancing west of the mountains encountered 180,000 Chinese. The right flank of the Eighth Army bore the main shock. As usual, the adversary charged wildly, to the sound of bugles, whistles, pipes and drum rolls. Having succeeded in forcing their way through the dark bottom of the steep-sided valleys, the Chinese suddenly appeared behind the United Nations troops, forcing them to split into isolated groups, then fighting them with the fanatical will to exterminate them.
Faced with a better equipped enemy, the Chinese used a tactic based on the effect of surprise, speed, darkness, mobility and terror. Their success was total. Three South Korean divisions on the right flank of the Eighth Army were wiped out at Tokchon. The American 2nd Division had to face a united riot of ferocity alone:it lost more than 4,000 of its 5,000 men as well as most of its artillery, communications equipment and engineers.