Profession: Adventurers (1973)

Henry is a young Englishman who decides to abandon the chaotic city life, but his journey into the Pacific Ocean ends with a shipwreck as a result of which he finds himself on a lost island. The only inhabitant of the island is a Japanese who, 30 years after the end of the Second World War, thinks he is still in conflict with the United States, and so, seeing the foreigner, he clumsily tries to attack him but ends up unexpectedly getting killed himself. Henry finds beautiful pearls on the beach, and after burying the deceased, takes off on a raft.