A few soldiers survived the massed banzai charges and attempted to evade capture by hiding in the jungles, but as an organization the regiment became defunct and the ranks were not replenished.

[1] By early 1944, much of northern China was nominally secure, and many units were being transferred to various islands in the Pacific in order to support the strained and hyperextended line of defensive positions.

[10][11][12] On 29 February 1944 the transport ship carrying the regiment, the Sakito Maru, was hit by a torpedo fired from the USS Trout (SS-202), an American submarine, just northeast of Saipan.

[6] The convoy's three escort destroyers dropped depth charges, sank the Trout, and then rescued the survivors of the sunken transport.

These troops, under Captain Masao Kubo, joined the island's garrison,[15] though nearly all would be killed during the Battle of Saipan in June and July 1944.

Sakae Ōba distinguished himself by taking command of a number of soldiers and sailors who had survived the battle, as well as Japanese civilians who looked to him for guidance and protection.

[13] In preparation for the imminent invasion of Guam by Allied forces, the main body of the 18th Regiment was situated on a mountain, with each company deployed to cover possible landing points in support of the island's defensive strategy.

[17] Despite fierce resistance, United States Army and Marine forces gained two beachheads by nightfall, straddling the Orote Peninsula on the west coast of the island, while the defenders either counterattacked or continued to fire on American positions with machine guns, artillery, and mortars.

[19] General Takashina devised a plan of attack to dislodge the 3rd Marine Division, which occupied the high ground at Asan, north of the Orote Peninsula.

Other units would attack the Marines or head to the beaches with demolition charges to destroy any ammunition or supply caches left by American forces.

Charging across open ground, they were hit by American artillery, mortars, and machine gun fire until they retreated into a mangrove swamp.

The assault of the 2nd Battalion, 18th Regiment, under Major Maruyama Chusa, struck the center of the 21st Marines, and was the scene of some of the most desperate hand-to-hand combat of the entire night.

Lacking any sort of anti-tank weaponry, the Japanese troops were unable to damage a single tank, and flowing over and past them, continued on down the draw.

Those troops who were unable to reach the draw regrouped and charged another point in the Marine line and fought hand-to-hand until their numbers became depleted.

The Japanese came close to overrunning the CP, but Yukioka's attack was blunted by desperate fighting during the Marines' counterattack supported by artillery and mortars.

The Japanese were prevented from overrunning the position only when every available Marine, including cooks, clerks, doctors, and some of the wounded, joined the fighting, before two companies of combat engineers arrived to support the defenders.

[26] It was also apparent to General Takashina that victory at Guam would be impossible, due to enormous losses in personnel, leadership, weapons, and morale.

Takashina decided that all remaining troops should escape to the interior of the island, in order to regroup, and carry on a guerrilla campaign to inflict as much damage as possible on the American forces.