And how far, as a matter of fact, has this assimilation gone. Not until these just one of the guys are really answered has the explanation been found, So that, after all, the prime cause which we must seek is not to be found in the external environment, but rather in the internal endowment. An effort to understand the ancient history of Japan encounters the same problem as that raised by her modern history. What mental characteristics led the Japanese a thousand years ago so to absorb the Chinese civilization, philosophy, and language that their own suffered a permanent arrest.