That the Gods of Yoga in the Hindu tradition could be both male and female, and there being no Sanskrit male/female pronoun for Divinity in India, was a strange concept when Buddhism arrived in China. But as usually happened with myth in culture, benign deities could be easily assimilated.
So when the Buddhists imported statues of Avalokiteshvara to China, the Chinese didn’t have a tradition of bisexual gods containing all the Divine male/female energy of creation, they understood the figure to be female. He/she became the “Goddess of Compassion” Kwan Yin, and in the manifestation as “The Regarder of the Cries of the World” in the Zen tradition, became “she”.
There is an ancient Taoist story of the separation of the Yin and Yang, which seems to be an origin for the Tao version of the Avolokiteshvara myth, The Regarder of the Cries of the World, and it’s about the origin of The Cry: tens of thousands of years ago just as humankind was beginning to be able to think, we were also beginning our separation from the One, in order to evolve and develop as humanity.
The Yin and the Yang separated and the pain of separation was expressed in the deep cry of the heart of mankind – a hunger and a yearning. In the story, our cries are always heard and our yearning to return to the whole is watched over with great compassion. And in order to return to the whole, we must learn to surrender our thinking-mind back to the One Reality: Consciousness.
The early Chinese Zen patriarchs were well versed in the Chinese classics, and they integrated Zen with the accepted philosophies of China, particularly Taoism. Each of the patriarchs contributed in their own way to integrating Buddhism and Taoism to form the uniqueness that is Zen: Taoism sees all phenomena in the world as Yin and Yang opposites, whilst Buddhism views all as emptiness, and Zen blends the two in the “vast Great Way that is neither easy or difficult” (Seng-ts’an 6th Century third Zen Patriarch).
And so, compassionately and non-judgementally, caring for the Whole and all the while watching over the innumerable, countless numbers of humanity . . . . the Goddess/God of compassion had made her way through India, through the lands of the Tao and Confucious, to Zen in Japan and, in listening to our cries of hunger . . . eventually to us in the West.
As usual, Zen changed with the culture and the culture changed with Zen. It is still changing in its own unique way, as the West continues the great awakening to Goddess.