Union of Appearance and Emptiness
Appearances arise vividly within the space of emptiness.
The union of appearance and emptiness recognizes that empty things can and do appear. Like a rainbow or a reflection - fully appearing yet without solid substance. This is the middle way of understanding reality.
Like a dream, like an illusion, like a city of gandharvas - so is birth, so is living, so is death.
This union prevents both nihilism and eternalism.
Vajracchedika Prajnaparamita