had moved inland in places but was still generally along the first line of defenses. The arrival of the tanks started the line moving on Red 3 and the end of Red 2 (the right flank, as viewed from the north), and by nightfall the line was about half-way across the island, only a short distance from the main runway. In addition, Maj. Michael P. Ryan, a company commander, had gathered together remnants of his company with diverse disconnected Marines and sailors from other landing waves, as well as two Sherman tanks, and had diverted them onto a more lightly defended section of Green Beach. This impromptu unit was later referred to as "Ryan's Orphans". Ryan, who had been thought to be dead, arranged for naval gunfire and mounted an attack that cleared the island's western end. The communication lines that the Japanese installed on the island had been laid shallowly and were destroyed in the naval bombardment, effectively preventing commander Keiji Shibazaki's direct control of his troops. In mid-afternoon, he and his staff abandoned the command post at the northeast end of the airfield, to allow it to be used to shelter and care for the wounded, and prepared to move to the south side of the island. He had ordered two of his Type 95 light tanks to act as a protective cover for the move, but a 5-inch naval artillery shell exploded in the midst of his headquarters personnel as they were assembled outside the central concrete command post, resulting in the death of the commander and most of his staff. This loss further complicated Japanese command problems. As night fell on the first day, the Japanese defenders kept up sporadic harassing fire, but did not launch an attack on the Marines clinging to their beachhead and the territory won in the day's hard fighting. With Rear Admiral Shibazaki killed and their communication lines torn up, each Japanese unit had been acting in isolation since the start of the naval bombardment. The Marines brought a battery of 75 mm Pack Howitzers ashore, unpacked them and set them up for action for the next day's fight, but most of the second wave was unable to land. They spent the night floating in the lagoon without food or water, trying to sleep in their Higgins boats. During the night, some Japanese marines swam to some of the wrecked LVTs