Why did they charge?
I've watched this movie a bunch of times since probably 1964-66 (WNEW CH5). Something that always puzzled me was that after defending their outmanned position from "hordes" of the enemy, they charge out of their "fort" to engage in bayonet fighting which doesn't work out too well.
All I can think of is that it made for a more exciting ending and made our soldiers look even braver for the folks back home in 1943.
Funny thing, back in 66 our folks told us the movie was over after the 'bushido bushwash' scene so we went to bed. Didn't find out till years later that wasn't the case.