The most common metaphors in Buddhism revolve around space. Enlightenment is compared to space. Likewise the teachings. Likewise the Dharmakaya, the universal body of Buddha. It is important that we understand what is meant by space. For us it implies vacuity, or absence. This is not at all how space is used in Buddhism.
Its use is more akin to brightness, or liberation, and the closest analogy is with water. Just as the fish does not realise he is in the ocean, the bird does not realise he is ‘in’ space. But there is a critical difference. If an object is placed in water, the water is displaced. If an object is placed in space the space is not displaced. Because space is everywhere, there is nowhere for it to be displaced to.
When we come into this room and sit, space is undiminished. And this place where we are sitting now contains both ‘us’ and ‘space’. If we examine our actual experience carefully, we can see this to be true.
So each ‘thing’ is both itself and space, both particular and universal, and one does not obstruct the other. We can in this way understand what Fujita means when he talks about practice as being ‘one piece Zen’.