The Japanese were basically to blame for the Manchurian Incident.
They blew up a railway section and quickly hid some where close. When the Chinese went to check on the explosion Japanese junior officers came out of hiding and blamed them for the explosion, pretending they were never there.
The Lytton Report was a famous report given by a group of people from the United Kingdom.
These people were given the task to go to Manchuria to see if Japan really did act out of self-defense. Their decision would help the League of nations decide whether to make Japan leave Manchuria or let them stay.
It took six months for them to decide, but the Lytton Report came up with the conclusion that Japan did not act out of self-defense.