Jurchen is the language of the Jurchen tribes, which founded the Chin dynasty in the early twelfth century, and is the oldest of the Tunguz languages for which there are extant materials in the native script.<BR>It is, however, almost impossible to reconstruct Jurchen phonology and establish the phonological system in that period due to the scarcity of linguistic materials. Although Chin-kuo yü-chieh金国語解has survived, the dictionary produced by the Jurchen themselves, the Nü-chen-tzu tzu-mu女真字字母, is not extant.<BR>Nevertheless, inasmuch as the Jurchen section of the Hua-i i-yü華夷訳語 (Chinese-Barbarian Glossaries) produced by the Ming Translators Bureau, namely Nü-chen-kuan i-yü女真館訳語, exists, one may reconstruct the Jurchen phonemes in the Ming period by means of the Chinese characters in the text used for the transcription of Jurchen. Therefore, the present state of knowledge of Ming Chinese phonology furnishes an important key to the solution of Jurchen sound equivalences transcribed by Chinese characters. It goes without saying also that linguistically the Manchu language plays a supplementary role in the solution of Jurchen phonology.<BR>Thus, the pronunciations of individual Jurchen characters, of which some are phonograms and some are ideograme, can be reconstructed by comparison of all occurrences of a given character with its transliterations into Chinese, and then by setting up the phonemes that leave the fewest contradictions. After establishing Ming Jurchen phonology in this fashion, it is then possibleto reconstruct Chin Jurchen phonology via historico-linguistic methods.<BR>As a result, one may discover such facts as: the Tunguz initial *p- was still preserved in Chin Jurchen, which then changed to *f-in Ming Jurchen; the back vowel series *a, *o, and *u contrasted with the front vowels *e, *ö, and *ü in addition to the neutral *i in the Chin period, whereas in the Ming period are found only five vowels, *a and *o of the back series, only *e in the front, and two neutral vowels *i and *u; etc. In addition, although it is known that there are no native Manchu words ending in a consonant but -n, some words ending in the consonant-*γ are to be found in Jurchen; there is no labial attraction in Jurchen, unlike Manchu; there is no phonological distinction between final-*n and-*η even in Chinese loans, as there is in Manchu; etc.