To make this point clear and to justify the claim for Zen that it transmits the essence of Buddhism and not its formulated articles of faith as are recorded in letters, it is necessary to strip the spirit of Buddhism off all its outer casings and appendages, which, hindering the working of its original life-force, are apt to make us take the unessential for the essential. We know that the acorn is so different from the oak, but as long as there is a continuation of growth, their identity is a logical conclusion. To see really into the nature of the acorn is to trace an uninterrupted development through its various historical stages. When the seed remains a seed and means nothing more, there is no life in it, it is a finished piece of work and except as an object of historical curiosity, it has no value whatever in our religious experience. In like manner, to determine the nature of Buddhism we must go along its whole line of development and see what are the healthiest and most vital germs in it which have brought it to the present state of maturity. When this is done, we shall see in what manner Zen is to be recognised as one of the various phases of Buddhism and in fact as the most essential factor in it. To comprehend fully, therefore, the constitution of any existent religion that has a long history, it is advisable to separate its founder from his teaching, as a most powerful determinant in the development of the latter. By this I mean, in the first place, that the founder so called had in the beginning no idea of being the founder of any religious system which would later grow up in his name; in the second that to his disciples, while he was yet alive, his personality was not regarded as independent of his teaching, at least as far as they were conscious of the fact; in the third that what was unconsciously working in their minds as regards the nature of their master’s personality came out in the foreground after his passing with all the possible intensity that had been latently gaining strength within them, and lastly that the personality of the founder grew up in his disciples’ minds so powerful as to make itself the very nucleus of his teaching, that is to say, the latter was made to serve as explanation of the meaning of the former.