Analysis of information sources in references of the Wikipedia article "Manchu people" in English language version.
The Jurchen settlements in the Amnok River region had been tributaries of Koryŏ since the establishment of the dynasty, when T'aejo Wang Kŏn heavily relied on a large segment of Jurchen cavalry to defeat the armies of Later Paekche. The position and status of these Jurchen is hard to determine using the framework of the Koryŏ and Liao states as reference, since the Jurchen leaders generally took care to steer a middle course between Koryŏ and Liao, changing sides or absconding whenever that was deemed the best course. As mentioned above, Koryŏ and Liao competed quite fiercely to obtain the allegiance of the Jurchen settlers who in the absence of large armies effectively controlled much of the frontier area outside the Koryŏ and Liao fortifications. These Jurchen communities were expert in handling the tension between Liao and Koryŏ, playing out divide-and-rule policies backed up by threats of border violence. It seems that the relationship between the semi-nomadic Jurchen and their peninsular neighbours bore much resemblance to the relationship between Chinese states and their nomad neighbours, as described by Thomas Barfield.