heaven ［天］ (, Pali deva-loka;  ten): In Buddhism, a realm of heavenly beings. Buddhism describes twenty-eight heavens or heavenly realms (twenty-six or twenty-seven according to different sources) in the threefold world. In ascending order, there are the six heavens in the world of desire, the eighteen heavens in the world of form, and the four heavens in the world of formlessness. These heavens are ranked in quality according to their elevation. The first and lowest heaven is the Heaven of the Four Heavenly Kings, located halfway up Mount Sumeru. The highest heaven is the Heaven of Neither Thought Nor No Thought. This heaven is regarded as the realm where those who have accumulated good fortune will be reborn, though it still belongs to the six paths of existence, a realm still encumbered by transmigration and delusion. Heaven, or the world of heavenly beings, is also the sixth of the Ten Worlds. Based on the philosophy of the Lotus Sutra, this can be viewed as a potential state or condition of human life. In The Object of Devotion for Observing the Mind, Nichiren (1222–1282) writes, “Joy is [the world] of heaven” (358). This describes the condition of contentment and joy one feels when released from suffering or upon satisfaction of some desire. Such joy disappears with the passage of time or with even a slight change in the circumstances. “Heaven” is therefore included within the six paths—states of life that are relatively passive and subject to changes in one’s surroundings.