Editor's Foreword.
The original of the Yüan-ch'ao-pi-shih 元朝祕史 （A Secret History of the Mongols） was compiled during the reigns of T'ai-tsu 太祖︀ and T'ai-tsung 太宗 of the Yüan dynasty. It was first written in the Mongolian language by the use of Uigur characters. At the beginning of the Ming dynasty, the court caused the writing to be retranscribed into Chinese ideographs. The new book contained the original text transliterated into Chinese characters, and a somewhat free literary Chinese translation as well as a colloquial Chinese translation of each word in the original. It was published under the title “Yüan-ch'ao-pi-shih.” The copies preserved, however, were so scarce that few men knew about it. Its first introduction into Japan dates from about 1901 or 1902 when WÊN of the T'ing-shih 文廷式 Ch'ing dynasty presented Dr. NAITÔ 內藤 and Dr. NAKA 那珂 with a MS. copy from the one in his possession.
On receiving this copy, Dr. NAKA was overjoyed as he anticipated its great value in his study of Mongolian history. But the work being in the Mongolian language transliterated into Chinese ideographs, it was imperative that one should possess an accurate knowledge of Mongolian in order to appreciate its real value. To his great regret, in those days there were almost none in Japan who were versed in the language. In spite of his repeated eager appeal to younger scholars to study Mongolian, they all hesitated, unable to bring themselves to undertake the study. Consequently, the professor finally determined to put the difficult task upon himself and was assiduously engaged in it. Now there were extremely few in reference-books the field. The Mongolian-Russian-French dictionary by KOWALEVSKY or the Mongolian-Russian dictionary by GOLSTUNSKY had not yet been introduced to Japan. Only SCHMIDT's grammar and dictionary containing only a very limited vocabulary were available. So the difficulty Dr. NAKA encountered was enormous. With his unrivalled enthusiasm and diligence, he at length mastered the Mongolian language and succeeded
