In this book the concept of “mountain, sea, sky, man” is used to express the “four realms of reality” of the Huayan school of Buddhism. Mountain corresponds to the realm of individual phenomena; sea corresponds to the realm of nonobstruction

between principle and phenomena; sky corresponds to the realm of the one principle (śūnyatā) ; and man corresponds to the realm of nonobstruction between phenomena, The same correspondence is expressed in the following verse:

Mountain:

From the sacred mountain of Huayan, entering the realm of reality; conventional truth is spoken in the realm of individual phenomena.

Sea:

Returning to the essence through the sea of Vairocana; Buddha is the realm of nonobstruction between principle and phenomena.

Sky:

The universal Dharmakaya is ineffable; in the realm of the one principle the essential nature is emptiness itself.

Man:

The vows of Samantabhadra span the three times; the realm of nonobstruction between phenomena—this is the Bodhisattva practice.