If it is at all the story I am thinking of, of it was a Japanese soldier on one of the Philippine Islands. They actually sent SEVERAL groups of people to the island, including groups of his own family, with bullhorns and pamphlets from Japan and his family, telling him the war was over. HE didn't believe it because he assumed Japan would never surrender (he didn't know about nuclear warheads....) and that all of it was a bunch of traps. They tried to save him for years but he just refused to believe Japan would lose in spite of his family and his own government telling him otherwise. Commitment or stupidity, take your pick.