If you can find it, the Grove paperback edition of the script of Rashomon contains several essays on the film, including one about The Great Rashomon Mystery. Well worth digging up and reading.
Yeah, don’t forget the last line of the movie was something to the effect that “these days you can’t believe what anyone is saying.”
This movie isn’t just the woodcutter telling about other people’s testimonies, it’s also the filmaker telling a story about a woodcutter who… You get the idea.
Trivia: The rain came from a fire engine. The town’s water supply went dry before they finished the shooting, which forced Kurosawa to use sound and lighting effects to suggest the pouring rain.