Factual error: The crescent as emblem on Saracen pennants is anachronistic as it appeared on Islamic military flags no sooner than the 15th century A.D.
Factual error: A very common error in First World War films. British soldiers were not permitted to shave their upper lips until 1916 - in 1914 almost all (unless physically unable to grow them) would have had moustaches.
Factual error: The group of Japanese soldiers who came to Cabanatuan following the guards desertion were not "secret police" with orders to execute the POWs as shown in the film. They were simply units who happened to temporarily halt at the camp during their retreat from the advancing Americans.
Factual error: In the scene where Swofford is playing the bugle a water tower in the background has an Air Combat Command emblem which is used by the Air Force and would not be seen on a marine base.
Suggested correction: That part of the movie was filmed at a Naval Air Facility in my hometown. That movie theater where they were watching Apocalypse Now was also in the same said NAF.
Factual error: When Hatsumomo wakes up late to torture little Chiyo again, her kimono is closed the wrong way.
Factual error: There are a couple of references throughout the movie to Ralph Fiennes' character as an "American diplomat" "of the League of Nations". The United States was not a member of the League, so there were no "American diplomats", as such, working for the League.