Review of “A-shou satsujin jiken” (1979)

One day, a young man walking past a construction site gets a bucket dropped on his head. When he comes out of the nearest clinic, he no longer remembers what he was supposed to do that day, so he goes home, where his broke flatmates insist on sharing the 50,000 yen he got from the construction crew. He then finds a dead body just outside his window. He resolves to identify the murderer, preferably as someone other than himself.