Nihon no ichiban nagai hi (1967)

If you liked Hiroshima I recommend Nihon no ichiban nagai hi (Japan's Longest Day (1967). http://www.imdb.com/title/tt0062041/ The latter film shows only the Japanese story. It shows some very interesting things that occurred, such as the some elements of the army seizing the palace and not allowing the Emperor to communicate with the outside world. They had to make a recording of the emperor's speech accepting the Potsdam Declaration, and entrust it to a chamberlain to hide it until legitimate army units regained control of the palace.

I believe that Nihon no ichiban nagai hi influenced Hiroshima, which was made 28 years later. Of course, some of the characters are common to both movies. In the older movie, the great Toshiro Mifune played Gen. Anami. In 1967 Mifune was 57, the exact age of Anami in 1945. I also thought the actor playing Anami, Hiromasa Ikegami, in Hiroshima was wonderful, but was perhaps too young. I believe his performance was inspired by Mifune's.