The above are further subdivided into 31 planes of existence.[web 4] Rebirths in some of the higher heavens, known as the Śuddhāvāsa Worlds or Pure Abodes, can be attained only by skilled Buddhist practitioners known as anāgāmis (non-returners). Rebirths in the Ārūpyadhātu (formless realms) can be attained by only those who can meditate on the arūpajhānas, the highest object of meditation.
Is there an answer to this question (If it cannot be answered, say "unanswerable"): What are skilled Buddhists called?
anāgāmis