The battle of Eniwetok (18-21 February 1944) was the second phase in the American conquest of Eniwetok Atoll in the Marshall Islands (Operation Catchpole).
Eniwetok Island was a long, fairly thin island. It was widest at the western end, and got narrower as it ran east. The eastern half was very narrow. There was a road near the lagoon shore on the western half of the island, and a track heading part of the way to the eastern end. The main buildings were close to half way along the island, on the lagoon side.
On 4 January 1944 the 1st Amphibious Brigade arrived on Eniwetok Atoll. The brigade contained 3,940 men, of whome 2,586 were posted on Eniwetok. Most of these men were posted on Parry Island, the location of the HQ of General Nishida Yoshimi, commander of the brigade. When the invasion began the Japanese had 779 troops from the brigade, 24 civilians and 5 naval personnel on Eniwetok, all under the command of Lt Col. Hashida Masahiro. The defenders had two flame throwers, thirteen grenade dischargers, twelve light machine guns, two heavy machine guns, one 50mm mortar, eleven 81mm mortars, one 20mm automatic gun, three 20mm cannons and three light tanks. The defenders were split into five groups. Three were posted on the lagoon shore. One was placed at a narrow neck of land to the east. One was to serve as a reserve. Most of the defences were made up of foxhole and trenches, but work had also begun on some concrete pillboxes.
The original American plan had been for the 106th Infantry to invade Eniwetok and Parry on the same day, but during the invasion of Engebi (17-18 February 1944) it became clear that both islands were more heavily defended than expected. As a result the plan was altered, with Eniwetok to be cleared first, followed by Parry.
The new plan was for two battalions of the 106th Infantry to attack on Yellow Beaches 1 (left) and 2 (right), on the lagoon side of Eniwetok. They would be supported by the 2nd Separate Tank Battalion (Marine), with the 3rd Battalion, 22nd Marines as the reserve. The commander of the 106th decided to use the 1st Battalion to clear the western end of the island, where most of the defences were believed to be, while the 3rd Battalion formed a blocking force to stop any Japanese troops in the east from interfering, while the rest of the battalion formed a reserve. Two platoons of medium tanks were to support the 1st Battalion, the third was to act as a reserve. Both beaches were towards the western end of the island. Both battalion commanders had similar plans. On the left one company would advance across to the ocean shore, forming a line across the island. The other would advance behind it, then mop up in the rear areas. On the right one company would stop on the lagoon side, the other would advance to the ocean shore, and the two would then advance west.
At 0710 on 18 February two cruisers and two destroyer opened fire from positions on the flanks of the boat lanes. At 0740 a third destroyer opened fire on targets to the east of the landing beaches and at 0810 a fourth destroyer opened fire from the ocean fire. This was the shortest and least powerful naval bombardment of the campaign.
At 0810 the naval gunfire was halted for 15 minutes to all for a carrier aircraft attack. The landings were delayed until 0915, and the first troops landed at 0917. For once the initial landings ran into problems. There was an eight foot high bluff just inland, which stopped the LVTs getting inland. The limited bombardment meant that many Japanese positions remained intact just behind the beach.
As a result there were problems along the line. Company B, landing on Yellow Beach 2, ran into a strongpoint almost at the centre of the landing zone, which held up the advance for some time. However this early resistance was fairly quickly overcome, and the first American troops reached the ocean shore by 1145. This didn't stop the heavy fighting, but by noon the 1st Battalion had an 'S' shaped front line that ran across the island and the 3rd Battalion had a rather straighter line.
The American troops had landed at the eastern end of the main Japanese defensive position, and they were now subjected to a strong counterattack, carried out by 300-400 men. This hit the western part of the line around the road, with other attacks stretching down to the ocean. In places the attack was supported by mortar fire, and in several places the Japanese broke through the first line before being stopped. The attack was over by 1245, and had failed to break the Americans.
At 1245 the main reserve force - the 3rd Battalion, 22nd Marines, was ordered to land to take over the left hand part of the 1st Battalion Line, in order to double the forces allocated to the push west. The Marines were ashore by 1425 and in place by 1605. The fresh troops were able to make good progress, and as darkness fell the Marines had reached the south-western corner of the island. This left a Japanese foothold in the north-west, and so Colonel Ayers ordered the attack to continue overnight. This meant that the army reached the north-western corner, but that still left a gap in between. At 0910 the Japanese attacked the Marine positions, and were repulsed, although one group of 30 did reach the battalion command post.
The fighting in the west came to an end on the morning of 20 February. The Marines found one of the strongest defensive positions, but overcame it with the support of tanks and artillery. By the end of the day the resistance in the west had been defeated, and there were no major attacks on the night of 20-21 February. On the morning of 21 February the Marines and the tanks were withdrawn ready for the invasion of Parry. This left the 1st Battalion, 106th, to mop up the western end of the fighting. One party of 22 enemy were found hiding on the ocean shore, and defeated after a fire fight that disrupted a swimming party further up the west coast!
On the east coast the 3rd Battalion attacked south at 0917 on 19 February with Company L on the left and Company K on the right Company I formed a reserve. Once again the Americans ran into undisturbed defence positions and had to eliminate them one by one. Even so, the Americans reached the ocean shore, and were able to turn east and attack east at 1515. This time Company L was on the left (lagoon) and Company I on the right (ocean), with Company K as the reserve. The attack was preceded by a 15 minute air strike. Progress was especially slow on the ocean front, where the undergrowth was especially well suited to the defence. One light tank was lost towards the end of the day, after it ran into a mine beyond American lines. However, overnight the Japanese attempted to defend the position of the tank, losing 40 men in the fight.
Once the Americans reached the long narrow eastern half of the island, organised resistance ended. However there were still isolated Japanese positions to deal with, and it took until 1630 on 21 February to reach the eastern end of the island. The battle had cost the Americans 37 dead and 94 wounded, the Japanese 800 dead and 23 prisoners.
The Americans then moved on to Parry Island, the last target in the atoll.