"Speak no evil" rabbit chasing

The "See no evil, Hear no evil, Speak no evil" Three Monkeys (or perhaps four: "Do no evil") may distantly relate to the Analects of Confucius: "Look not at what is contrary to propriety; listen not to what is contrary to propriety; speak not what is contrary to propriety; make no movement which is contrary to propriety". At any rate a philosophy which used this 3-fold admonition may have come from China to Japan in the 8'th century, and the maxim became part of the folk religion of Koshin. The saying in Japanese is "see not, hear not, speak not", in which the negation part "zaru" is a pun on the word for monkey. Who could resist?

The tie-in of Koshin with the monkeys has to do with the Three Corpses (or Worms), malevolent creatures that live inside humans. Every 57'th day in a 60-day cycle, while the human sleeps, the creatures ascend to heaven and report on their host's deeds, taking special delight in reporting the misdeeds in hopes of punishment for the poor human. (your own personal accusers)

At first it was only the elite (the ones who first adapted the faith) who tried to stay awake all that day and night to keep the 3 from reporting, but apparently the notion of having a regular all-night party became popular. That there is a relationship between the monkeys not seeing or reporting on evil and the hope that the evil spirits will do the same seems clear enough, but the details aren't.