In one scene Laura imagined the historical possibility of The 9th Division of the United States Army landed in Formosa (Taiwan) rather than Okinawa. But the 9th division was active in Northern Africa and Southern Europe during the World War II, not in East Asia.
In one scene the narrator talked about the tomb of Commodore Perry in Naha, Okinawa. In fact Matthew C. Perry's grave is at Newport of Rhode Island, not in Okinawa. The image shown in the film was actually a monument erecting in honor of Commodore Perry's landing in Okinawa, not his tombstone.