The Burmese Harp is a complex movie delivering simple themes. It's based on a book originally published in a children's magazine in Japan, and this makes sense because - while the film is anti-war - it portrays pacifism as a higher calling and a great responsibility and sacrifice, as opposed to condemning war as a great evil.
The whitewash of the Japanese presence in Burma in the film doesn't seem as scandalous as it might because of this origin. Furthermore, comparing the film to similar Hollywood war films of the time makes it seem both less outrageous in its historical inaccuracies and more typical in its melodramatic heavy hand with regards to its themes. The protagonist's journey from soldier to monk certainly has realistic and complex moments that hint at the dark side of such a journey. But too much of the story seems devoted to the kind of straight-faced do-gooder style ethical stances that seem more at home in a Douglas Sirk film (where Sirk, of course, would slyly parody them).
Ichikawa was a studio journeyman before The Burmese Harp, making this film and its subsequent international success his opportunity to cross over into artistry - something he would capitalize on frequently afterwards. But here, he still seems very much encumbered by a desire to avoid challenging his audience. Despite its deeply religious and anti-war themes, The Burmese Harp ends up overly sentimental and toothless - more Saving Private Ryan than The Thin Red Line.