What's that movie?.......?

I don't know what year it's from, but I know it's not recent. These women get stranded during the war in the ocean (I think there's 3 of them) and they have to swim to shore, where they find a concentration camp (I think the camp is in Japan). They are taken as prisoners. The one part I really remember is when the one woman says something about the Japanese flag looking like a "poached egg" and so one of the soldiers makes her kneel in the dirt with a log on her legs, so she can't sit back and spikes at her front, so she can't fall forward. She is forced to sit like this for a long time and when the guy comes back, he pretends like he's going to chop off her head, but he just cuts off a piece of her hair with his sword. What is the name of this movie??? It's driving me crazy!!!!