Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.
Q: Context: Die Jakobsleiter (Jacob's Ladder) is an oratorio by Arnold Schoenberg that marks his transition from a contextual or free atonality to the twelve-tone technique anticipated in the oratorio's use of hexachords.
Question: Which is the basis of Die Jakobsleiter?
A:
jacob's ladder