The book is hard to find so the link is apricated.

I find when it comes to books on Zen a good practice is to not to hold the words to tightly. Zen tends to use language to ‘slap’ the student so that they might avoid falling into that temptation of mistaking the map for the territory. Though it may not always appear so, Zen never asks that the student to understand or believe.

Man is originally endowed and invested with Hara. But when, as a rational being, he loses what is embodied in Hara it become his task to regain it.

To rediscover the unity concealed in the contradictions through which he perceives life intellectually is the nerve of his existence. As a rational being he feels himself suspended between the opposite poles of heaven and earth, spirit and nature. This means first the dichotomy of unconscious nature and of the mind which urges him to ever increasing consciousness; and second the dichotomy of his time-space reality on this earth and the Divine beyond time and space. Man’s whole existence is influenced by the tormenting tension of these opposites and so he is forever in search of a life-form in which this tension will be resolved. – Karlfried Graf Durckheim