https://letterboxd.com/film/the-ants-2006/

Waichi OKUMURA, a 80- year-old WWII veteran and other 2600 ordered to stay on in China and fight along with the Chinese nationalists in the post-1945 civil war. Racing against the time, he powerfully campaigns to expose the secret military orders that kept them in China years after Japan had surrendered.

I recently finished William Hinton’s Fanshen, which talks about this a bit, and I also just saw the documentary The Emperor’s Naked Army Marches On, which is about a Japanese WWII veteran trying to coax confessions out of his former leaders. This one seems pretty obscure but if anyone knows where i can get my hands on it I would be very grateful!