论带“五等”字号的虚封爵——晋宋之际国家官爵制度上的变化之一

晋宋之际，国家官爵制度上发生的重要变化之一就是带“五等”字号虚封爵的出现。晋末特殊军事政治形势之下，京口北府集团凭借强势军功击败高门士族，取得压倒性的军事政治优势，京口北府军功受益阶层由此形成。带“五等”字号虚封爵适时地出现则成为这个现实政治变化的典型表现之一。笔者从这种虚封爵产生的时间和目的进行详细分析，以为正是出于酬赏义熙初年京口北府集团建义之功，朝廷才创设了这种虚封爵。这种虚封爵突破既有的门阀制度优势，确立了以军功为核心的分享军事政治利益的价值导向。这使得京口北府集团凭借军功所获取的军事政治利益不仅在制度层面上得到保障，而且在价值层面上取得其正当性和合法性，也就在这个时候，京口北府军功利益阶层得以成立。酬赏军功的这一目的也直接决定了虚封爵的若干特点，对此，笔者也予以分析说明。

On the Ranks with the Characters of ＂Wu Deng＂ between Dong Jin and Song Dynasty

Great changes had taken place in the regional and central administrative systems between Dong Jin and Song Dynasties. One of them was that the ranks with the words of ＂Wu Deng＂ （five degrees） were established. In my view, the ranks were directly brought about by the rising of Jing Kou Group. In the paper I analyze the time when the ranks were established, and the reason why they were established as well. So I make a conclusion that the only aim that the ranks were established by the central government of Dong Jin Dynasty was to reward the generals of Jing Kou Group for their great merits to save and rebuild up the dynasty itself. And at the same time it showed that under the special circumstance Jing Kou Group had got great military and political advantages over the aristocrats, and then the formation of the military meritocracy of Jing Kou Group was finished. And at last we discuss the special characters of the ranks.