Marine patrols, such as Puller's trek to Gilnit, depended on bearers recruited from the villages of western New Britain who were thoroughly familiar with the local trail net.
Department of Defense (USMC) photo 72836
Despite this assistance from the air, the march to Gilnit taxed the ingenuity of the Marines involved and hardened them for future action. This toughening-up seemed especially desirable to Puller, who had led many a patrol during the American intervention in Nicaragua, 1927-1933. The division's supply clerks, aware of the officer's disdain for creature comforts, were startled by requisitions from the patrol for hundreds of bottles of insect repellent. Puller had his reasons, however. According to one veteran of the Gilnit operation, "We were always soaked and everything we owned was likewise, and that lotion made the best damned stuff to start a fire with that you ever saw."
As Puller's Marines pushed toward Gilnit on the Itni River, they killed perhaps 75 Japanese and captured one straggler, along with some weapons and odds and ends of equipment. An abandoned pack contained an American flag, probably captured by a soldier of the 141st Infantry during Japan's conquest of the Philippines. After reaching Gilnit, the patrol fanned out but encountered no opposition. Puller's Marines made contact with an Army patrol from the Cape Merkus beachhead and then headed toward the north coast, beginning on 16 February.
To the west, Company B, 1st Marines, boarded landing craft on 12 February and crossed the Dampier Strait to occupy Rooke Island, some fifteen miles from the coast of New Britain. The division's intelligence specialists concluded correctly that the garrison had departed. Indeed, the transfer began on 6 December 1943, roughly three weeks before the landings at Cape Gloucester, when Colonel Jiro Sato and half of his 500-man 51st Reconnaissance Regiment, sailed off to Cape Bushing. Sato then led his command up the Itni River and joined the main body of the Matsuda Force east of Mount Talawe. Instead of committing Sato's troops to the defense of Hill 660, Matsuda directed him to delay the elements of the 5th Marines and 1st Marines that were converging over the inland trail net. Sato succeeded in checking the Hunt patrol on 28 January and buying time for Matsuda's retreat, not to the south, but, as the documents captured at the general's abandoned headquarters confirmed, along the northern coast, with the 51st Reconnaissance Regiment initially serving as the rear guard.
On 12 February 1944, infantrymen of Company B, from LtCol Walker A. Reaves's 1st Battalion, 1st Marines, advance inland on Rooke Island, west of New Britain, but find that the Japanese have withdrawn.
Department of Defense (USMC) photo 79181
Once the Marines realized what Matsuda had in mind, cutting the line of retreat assumed the highest priority, as demonstrated by the withdrawal of the 1st Battalion, 5th Marines, from the Puller patrol on the very eve of the march toward Gilnit. As early as 3 February, Rupertus concluded that the Japanese could no longer mount a counterattack on the airfields and began devoting all his energy and resources to destroying the retreating Japanese. The division commander chose Selden's 5th Marines, now restored to three-battalion strength, to conduct the pursuit. While Petras and his light aircraft scouted the coastal track, landing craft stood ready to embark elements of the regiment and position them to cut off and destroy the Matsuda Force. Bad weather hampered Selden's Marines; clouds concealed the enemy from aerial observation, and a boiling surf ruled out landings over certain beaches. With about 5,000 Marines, and some Army dog handlers and their animals, the colonel rotated his battalions, sending out fresh troops each day and using 10 LCMs in attempts to leapfrog the retreating Japanese. "With few exceptions, men were not called upon to make marches on two successive days," Selden recalled. "After a one-day hike, they either remained at that camp for three or four days or made the next jump by LCMs." At any point along the coastal track, the enemy might have concealed himself in the dense jungle and sprung a deadly ambush, but he did not. Selden, for instance, expected a battle for the Japanese supply point at Iboki Point, but the enemy faded away. Instead of encountering resistance by a determined and skillful rear guard, the 5th Marines found only stragglers, some of them sick or wounded. Nevertheless, the regimental commander could take pride in maintaining unremitting pressure on the retreating enemy "without loss or even having a man wounded" and occupying Iboki Point on 24 February.
Meanwhile, American amphibious forces had seized Kwajalein and Eniwetok Atolls in the Marshall Islands, as the Central Pacific offensive gathered momentum. Further to complicate Japanese strategy, carrier strikes proved that Truk had become too vulnerable to continue serving as a major naval base. The enemy, conscious of the threat to his inner perimeter that was developing to the north, decided to pull back his fleet units from Truk and his aircraft from Rabaul. On 19 February—just two days after the Americans invaded Eniwetok—Japanese fighters at Rabaul took off for the last time to challenge an American air raid. When the bombers returned on the following day, not a single operational Japanese fighter remained at the airfields there.