Kamigami ga kieta hi (1989)

Shinichi's mother died after suffering for many years after being exposed to radiation in Nagasaki from the atomic bomb. On the way to his mother's grave Shinichi falls from his motorcycle and is injured. The man who finds Shinichi injured brings Shinichi to a guest house nearby. Shinichi, like his mother, is suffering from leukemia. But he still wants to fulfill his promise of meeting up with his best friends Takashi and Hiroshi in front of his mothers grave.