阿保機即位疑案重審——從草原傳統向華夏文化轉型中的另類歷史敘述

Revisiting Abaoji’s Rise to Power: Incongruous Historical Narratives and the Translation of Steppe Tradition into Sinitic Culture

阿保機即位問題堪稱契丹開國史的頭號疑案，既往研究希望在遼朝、中原兩大文獻系統間做出非此即彼的判斷，始終莫衷一是。《遼史》所述阿保機奉遙輦可汗遺命即位之說與史實相去甚遠，由此展開的一系列記載皆經不起推敲，是遼朝後期史官為塑造華夏正統性而加以改撰的結果。中原文獻所記相關史事，源流有別，價值殊異，所謂自稱國王、八部選汗之說信而有徵，很大程度上反映了契丹建國以前歷史的實態，而後來衍生出的漢城鹽池、誘殺諸部云云則係傳聞附會。作為建國以前選汗傳統的凝縮與寫照，「遙輦」源於契丹北遷後以饒樂水之名統稱部落聯盟中的不同汗族，將汗權選任範圍限定在契丹舊部之內，但也構成了較晚加入契丹集團的阿保機家族攫取最高權力、僭陞汗族的制度背景。從遙輦到阿保機的權力更迭，屬於同一政治體名號下統治家族的改換，在草原政治傳統中並不罕見，但在華夏歷史書寫中卻難覓蹤跡；遼後期史官將其打扮成委國異姓的顧命，是一種不倫不類的歷史敘述，集中呈現出文化轉型過程中草原傳統被強行納入華夏譜系所面臨的困境。

One of the key questions in the study of the history of the founding of the Khitan state is how Abaoji 阿保機 (posthumously known as Emperor Taizu of Liao, r. 916–926) rose to power. Previous research has sought to confirm the story of his rise recorded in either the sources produced by the Liao court or the accounts found scattered in documents of the Central Plains, but none have been able to definitively determine which narrative is correct. The record found within the History of Liao, wherein Abaoji assumes the role of khagan through the bequest of the Yaonian Khagan, is far from what actually happened, and the series of accounts that have arisen from its telling of events likewise do not stand up to scrutiny. This is because the story was the result of the editorial work of later Liao dynasty court historians, who were concerned with constructing a narrative that conformed to Sinitic traditions of legitimate dynastic succession. In contrast, the relevant accounts in the documents of the Central Plains come from different sources and vary in degrees of usefulness. Their suggestions that Abaoji called himself “king” (guowang 國王) or that the Eight Tribes nominated him as khagan, for example, can be supported as reliable and are seen to be more representative of the circumstances prior to the founding of the Khitan state. However, the records of certain later incidents, such as the ambush of tribal leaders at the salt ponds of a “Chinese City” (hancheng 漢城), were legends and embellishments. It is the history of “Yaonian” 遙輦, which is derived from the destination of the Khitan northern migration—namely the Raole river—that provides a snapshot and condensed account of the predynastic tradition of appointing khagan. Traditionally, there were different khagans in the tribal coalition, but succession was restricted to members of the old tribes of the Khitan. It was against this institutional background that the clan of Abaoji, later arrivals to the Khitan coalition, managed to rise to the highest position of power and usurp the ruling khagan house. The power shift from the Yaonian Khagan to Abaoji represents a change in the ruling house without a change in the name of the polity. Such a change was not a particularly unusual occurrence in the political traditions of the steppe, but is hard to trace in the historiographical writings of the Sinitic world. The court historians of the late Liao, for example, dressed the transition up as a dying imperial edict entrusting the state from the ruler to a different house. This anomalous historical narrative, however, does not seem to fit, thereby demonstrating the problems researchers encounter when steppe cultural traditions that had been in flux were artificially inserted into the framework of political succession based on the Sinitic tradition.