After the American liberation landing, the town was occupied by the 'Shigemi Detachment', named after Brigadier General Shigemi. This detachment had over 1,000 men, mortars and machine guns. , they withdrew to San Manuel on January 17, 1945 with 33 tanks remaining.

Battle of San Manuel
After the battles at Urdaneta and Binalonan, the 7th Tank Regiment 'Shigemi Detachment', named after Brigadier General Shigemi, dug in at San Manuel. This detachment had over 1,000 men, mortars and machine guns. Shigemi resovled to fight to the death and his forces dug in along a fan-shaped defensive line, converting most of their 40 Type 97 Chi-Ha tanks and 5 Type 95 light tanks into fortified bunkers, by digging them into the ground with the turret above, to serve as fixed positions. A total of 75 earthen emplacements, protected by rifle and machine gun pits established at key points around the outskirts of the town, with 30 tanks assigned to them, and the remainer as moblie reserves in the town. In support was the 1st Battalion of the 2nd Moblie Infantry Regiment with fifteen 75mm guns, some 47mm anti-tank guns and 15 mortars.

Pre-Bombardment
San Manuel began on January 19, 1945 with a five day bombardment. The American assualt began on January 23rd by the the US Army 25th Division, 161st Infantry Regiment, supported by tanks of the 716th Tank Battalion, capturing the hills to the south of town.

First Attack Haulted
The main attack on the town began on January 24th, by the 1st Battalion supported by six Shermans but was halted by a drainage ditch and 47mm anti-tank fire. One tank was lost, 4 disabled and one immobalized, and 8 KIA 63 WIA.

Southern Attack & House-To-House Fighting
The 2nd Battalion attacked from the south towards the town. The first assalut was stopped by three Japanese tank. A second attack gained a foothold in town and destroyed 5 tanks. The next day the attacked reinfornced by the 1st and 3rd Battalions, and a slow house-to-house fight took place. On the morning of January 26, 1945 assualted the area with over a dozen Sherman tanks, firing on the Japanese from a safe distance, destroying most.

Banzai Attack & End of the Battle
By the 27th, the remaing tanks were was pushed back to the hills. Knowing they had no route of escape, the 7th Tank Regiment carried out a Banzai attack at 0100 on January 28th with remaining 13 tanks. Ten were destroyed with before breaking the American lines, the remaining three retreated towards the hills.

By 1330 on the 28th the Japanese had abandoned San Manuel. The Japanese lost all their tanks, heavy weapons and 750 KIA. Commander Shigemi and 7th Tank Regiment commander Colonel Maeda were both killed. After four days of intense close-combat the 161st liberated the town. For their gallantry in the battle for San Manuel, both Company E and Cannon Company, 161st Infantry were awarded Presidential Unit Citations. After the battle, the US Army 32nd Infantry Division arrived at this town, then proceeded to San Nicolas.