Obake Entotsu no Uta
O-bake Entotsu no Uta ／ Song of the Chimney Ghosts ／ おばけ煙突のうた
Description
One day in 1945, children in Tokyo mistake the distant factory smoke of Shitamachi for ghosts in the sky, though their happy playtime is soon destroyed by the arrival of American bombers. (Source: The Anime Encyclopedia)