© 2015 Disney
After Yoda heard the voice of long-dead Qui-Gon Jinn, he let the Force guide him to the swamp world of Dagobah, one of the purest places in the galaxy. There, amid Dagobah’s abundant life, he spoke with Qui-Gon’s spirit and took the first steps towards learning to retain his consciousness after death.
After the Empire’s rise, Yoda returned to Dagobah to live in exile. There he communed with Qui-Gon, meditated on the connections between the living and cosmic Force, and awaited the coming of a new hope for the Jedi Order.
That hope was Luke Skywalker, the son of Anakin Skywalker. Obi-Wan Kenobi appeared to Luke as a Force spirit and guided him to Dagobah, where Yoda trained the youth as a Jedi. But Luke unwisely cut his lessons short, rushing off to Bespin in an attempt to save his friends from Darth Vader.
Luke kept his promise and returned to Dagobah, where Yoda told him he must confront Darth Vader. The ancient Jedi Master then died, passing into the Force, and Luke spoke with Obi-Wan’s spirit. He was certain – as his mother Padmé Amidala had once been -- that there was still good in Vader.