Viru would be a tougher problem. The narrow entrance to the harbor was flanked by high cliffs and covered by a 3-inch coast defense gun. Numerous enemy machine guns, including .50-caliber models, occupied supporting positions. Most of the defenses were oriented toward an attack from the sea, so American leaders quickly decided to conduct an overland approach. But that was not easy either, given the difficulty of the trails. After reconnaissance and consultation with higher headquarters, Currin decided to take his Raiders by rubber boat to Regi, where they would begin their trek.
The assault on Viru would be a double envelopment. Lieutenant Devillo W. Brown’s 3d Platoon, designated Task Force B, would take the lightly defended village of Tombe on the eastern side of the harbor. The remainder of the force would attack the main enemy defenses at Tetemara on the opposite shore. The simultaneous assaults were to take place on the originally scheduled D-day. Once the approaches were secured, APDs would land two Army infantry companies.
The Marines departed Segi the evening of 27 June and landed at Regi just after midnight. They rested a few hours and then moved out single file on the narrow trail. Company O took the lead with Company P bringing up the rear. Native scouts served as guides and the point. The small force had not gone very far when the path disappeared into a swamp. After three hours of tough movement, firing erupted at the end of the column. One of the Japanese patrols known to be in the area had stumbled upon the rear guard. The Raiders killed four of the enemy and suffered no casualties. About an hour later a Japanese force of about 20 men, possibly the same force, came up from a side trail and hit the rear guard in the flank. After an hour of firing the enemy broke off the action. There were no known casualties on either side, but the five-man rear point failed to rejoin the Marine column. (They later turned up back at Segi.)
The Raiders crossed the Mohi River late in the afternoon and set up a perimeter defense for the night. The wicked terrain and the two forced halts convinced Currin that he would not make it to Viru in time for D-day. Since he no longer had any working radios, he sent two native runners to Kennedy asking him to relay a message to higher command that the 4th Raiders would be a day late in making its attack.
After a miserable rainy night, the Marines moved out. They reached the Choi River late in the morning. As the rear elements crossed, an enemy force on a hill 300 yards to the battalion’s flank opened up with heavy fire from machine guns and rifles. The battalion halted again as Currin tried to determine what was transpiring. After about three hours he knew that his rear had successfully engaged a small unit, probably another enemy patrol, so the remainder of the force proceeded on its way. The Raiders crossed the snake-like Choi River twice more before halting for the night at 1800. The 3d Platoon reached the perimeter at 2100. They had lost five killed and another man was wounded, but they had counted 18 enemy dead.