This episode explores the concept of Buddha-nature within various Buddhist traditions, addressing its origins and interpretations. It highlights that the widespread understanding of universal Buddha-nature in Western Buddhism often stems from Zen teachings by figures like D.T. Suzuki and Tibetan commentaries rather than directly from specific sutras. While sutras such as the Flower Garland and Lankavatara do discuss Buddha-nature, the Ratnagotravibhāga-Mahāyāna-Uttaratantra is identified as a significant commentarial source that synthesizes these teachings. The text also contrasts these perspectives with the Tiantai and Nichiren schools' unique emphasis on "mutual possession of the ten realms" and the "threefold Buddha-nature," which assert not just potential but active and ongoing Buddhahood within all beings, distinguishing them from other interpretations that might view Buddha-nature as a latent potential realized by cutting off other states of existence.