You don’t often get to see Japanese films about WWII, so it is interesting to get the “loser’s” perspective - especially how they explain the cause of the war and the maner in which they portray American and British forces. This is a good list of war films popular in Japan (with video clips):
Another Japanese title is the various versions of the manga Barefoot Gen: it’s been made into two anime versions and three live action versions. I must confess I haven’t watched any of them, but only read the original manga.
An alternate-history version of the Pacific War is given by the anime series Zipang. In it, a 21st-century Japanese warship is mysteriously sent back to 1941, where it witnesses (but does not take part in) the Battle of Midway, then spends the rest of the series trying to evade both the US Navy and the Imperial Japanese Navy, and trying not to change history by taking part in the war – since with 21st-century technology they are the most powerful warship in the Pacific. Though it has fantasy elements, it explores the attitudes of contemporary sailors (including Admiral Yamamoto) and 21st-century Japanese sailors to the Pacific War.
Recent PRC film with good production values. There is a scene toward the end where the protagonist is fighting with the Chinese forces during the Korean War (not immediately related to the OP, but still relevant).
My personal favorite is The Burmese Harp. It’s such a beautiful movie that I can let go of my suspicion that rape, murder, torture, etc. was practiced by every single Japanese unit. If such units were a majority IRL, they seem to be the minority (to the point of non-existance) of those portrayed in Japanese movies.
I admire Masaki Kobayshi’s trilogy The Human Condition. It’s about a humanitarian Japanese who takes a job as a civillian employee in Manchuria, only to discover that he’s a cog in a slave-labor machine. It shows how a lot of assholes thrive in a militaristic system, but that doesn’t mean all Japanese are bad. That I can agree with.
Also good is The Tunnel segment from Kurosawa’s Dreams
If the Japanese invasion of Manchuria counts as part of WW2, then Millennium Actress is, in part, a WW2 movie, since the protagonist’s one true love, the dissident that she looked for all her life, died in Manchuria (though, of course, she never knew that).
There’s a strange propaganda cartoon movie which was finished just before Japan lost the war in the Pacific, ISTR being told. It’s called Momotaro’s Divine Sea Warriors. It’s on youtube in nine parts, and I watched the whole thing on one rainy weekend. It was rather bizarre from beginning to end. It’s about young men (all as animal characters) being drafted and trained as soldiers and then sent to Pacific islands to fight. I especially like the end, when American soldiers are shown. They’re drawn weirdly, and speak in vaguely English-sounding gibberish. And apparently, they’re total gutless cowards. I’ll have to watch it again.