During Japan's initial advance, an SNLF (Special Naval Landing Force) platoon was sent to garrison Atuk, an Island in the Caroline Cain. Several days after landing, the platoon was attacked by a swarm of zombies from the inland jungle. Initial casualties were high.
Without information about the nature of their attackers or the correct means of destruction, the SNLF were driven to a fortified mountaintop on the north end of the island. Ironically, as the wounded were left to die, the surviving troops spared themselves the danger of taking infected comrades with them. The platoon remained stranded in their mountaintop fortress for several days, lacking food, low on water, and cut off from the outside world. all this time, the zombies were besieging their position, unable to scale the steep cliffs but preventing any chance of escape.
After two weeks of imprisonment, Ashi Nakamura, a platoon sniper, discovered that a headshot was fatal to a zombie. This knowledge allowed the Japanese to eventually combat their attackers. After dispatching the zombies surrounding them with rifle fire, they advanced further for a full sweep of the island and were rescued.