Much attention has been drawn to the history of the West-Mongolian Dorben Oriyad from the early 17th century when they first appeared as the Kalmyks in Russian sources to the end of the same century when they were united under Galdan of the Jun Γar (Dzungars). The first to discuss the subject in Japan was Masao MORI, who, in the early 1950's, quoted Pallas, Howorth and Baddeley and corrected their errors. He was followed by Akira HANEDA, Hidehiro OKADA, Zuiho YAMAGUCHI and Hiroshi WAKAMATSU. Especially WAKAMATSU gives a consistent description of the history of the so-called "Dzungar Khanate" from its supposed founder Qara Qula down through Baratur Qong Tayiji, Sengge and Galdan who established a kingdom of integrated Oyirad tribes. Therefore his work has since been regarded as a standard reference for Japanese students of the history of that period. Mainly basing himself on Russian documents, WAKAMATSU argued that Qara Qula of the Dzungars had already been the leader of all the Dorben Oyirad as early as in the beginning of the 17th century, and that the Dzungar leadership as such was further strengthened at the time of his son Baratur Qong Tayiji. This view, which is derived from the old views of Pallas and Zlatkin, however, is found to be contrary to historical facts that are deduced from a closer examination of the Russian documents and Mongolian sources. It turns out that the Dzungar chiefs previous to Galdan were never supreme leaders of the Dorben Oyirad. For example, Mongolian sources reveal that in the days of Qara Qula it was Bayibaras Qaran of Qosud that led the Oyirad campaigns against the Qalqa Mongols. Bogatyr' Talai Taisha, who figured as the head Taisha of the Kalmyks of 1616 in Russian documents and was identified by Pallas with Baratur Qong Tayiji, is actually Dalai Tayisi of the Dorbed. Baibagish, a chief murdered in the internal disturbances of the Kalmyks in the 1620's who was regarded as a son of Qara Qula by WAKAMATSU and Zlatkin, was nobody but Bayibaras Qaran of the Qosud. Also doubtful is the theory of Zlatkin, who thinks that the "Dzungar Khanate" was established in 1635, the year in which Baratur, the son of Qara Qula, assumed the title of Qong Tayiji. The supreme leader of the Dorben Oyirad at that time was Guusi Qaran, a younger brother of the murdered Bayibaras. We may safely conclude that a Dzungar Khanate did not come into existence until the time when Galdan who had succeeded Sengge, attacked Vcirtu cecen Qaran of the Qosud, took over his subjects and assumed the title of the Qaran of the Dorben Oyirad in 1676. The root of the misconception by Pallas, Zlatkin and WAKAMATSU lies in their projecting the images of the later Dzungar Khans back to the times of the still disunited Oyirad of the 17th century.