In Religion of No-Religion he discusses how the Buddha taught the method of awakening through the experience of no-self, no-concept, and no-religion. This technique of short-circuiting the mind is seen today in the method of instruction centered upon Zen koans. In contrast to the intellectual methods of Zen, the Tibetan, or Vajrayana school, retained much more of the original Indian flavor of Mahayana Buddhism, and in Wisdom of the Mountains Watts provides an introduction to Tibetan Buddhism by explaining its unique practices. In the final chapter, Transcending Duality, Alan Watts explores the male and female symbolism of Tantric yoga and explores the unity of polar opposites as a form of resonance.