唐代七言古詩格律探論

On the Tone Scheme of the Seven-character Poems of the Tang Dynasty

學者對七言詩的起源，眾說紛紜，或以為出於楚騷，或以為源於樂府，或以為濫觴於民歌。七言詩首見於漢代，但今天所見漢代七言詩極少。魏晉南北朝時期，七言所作漸多，惟當時七言古詩的觀念，包含了整齊的七言體和含有雜言的七言體，而且也包含了樂府民歌在內。到了唐代，又有所謂歌行體的七言古詩，這些歌行體的七古，其實是唐代詩人新創的樂府，但也都被視為七言古詩的一種。後人對歌行體與七古的看法，不外兩種：一是把歌行等同於七古，一是於七古之外，別立歌行一體，惟從杜甫開始，歌行體已呈現出和七古靠近的趨勢。事實上，我們今天談到唐人的七言古詩，是包含了齊言的七言詩和以七言為主的雜言詩在內。本文要討論的主要是唐人齊言七言古詩的聲調，排除了雜言的七古，也排除了句句押韻的柏梁體和奇數句的七古，因為這些體裁的七古和齊言七古在聲調格律上有很大的不同，無法等量齊觀，同文並論。惟本文的七古則包含了歌行體和樂府詩中的齊言詩。另外，在取材上本文則以李白、高適、杜甫、韓愈、李商隱等重要詩人為主。唐人齊言七古又可分為轉韻七古和一韻到底的七古。在平仄聲調上，轉韻七古往往雜有律句，這種情形在近體成熟之前，只能說是偶合於律句，但在唐代近體成熟之後，則是詩人意識地創作了。一韻到底的七古在形式上可分為平韻和仄韻兩類。明清以來的論詩者都認為，平韻到底七古不可雜入律句，仄韻到底七古因為用仄韻，已和近體詩用平韻有別，不會落調，因此可摻雜律句。但本文以檢索統計的方法研究後發現，實際情形和明清人之說是有出入的。 This article, at first, reviews the tone scheme theories of seven-character poems in Ming and Ching Dynasties and then investigates the tone patterns of more than one thousand poems by Tang poets. The tone pattern of seven-character poems by Tang poets can be divided into two types: the so-called multiple rhyme-word seven-character poems, and one rhyme-word seven-character poems. The so-called multiple rhyme-word seven-character poems follow the regulation whose tone scheme is very similar to that of regulated poems, and the tone scheme of the one rhyme-word seven-character poems is, on the other hand, very similar to that of the old style poems. Lastly, this paper finds that the Tang poets may not strictly abide by the fore-mentioned regulation. Where there is a leeway in between, poets would write freely in terms of tone scheme.

This article, at first, reviews the tone scheme theories of seven-character poems in Ming and Ching Dynasties and then investigates the tone patterns of more than one thousand poems by Tang poets. The tone pattern of seven-character poems by Tang poets can be divided into two types: the so-called multiple rhyme-word seven-character poems, and one rhyme-word seven-character poems. The so-called multiple rhyme-word seven-character poems follow the regulation whose tone scheme is very similar to that of regulated poems, and the tone scheme of the one rhyme-word seven-character poems is, on the other hand, very similar to that of the old style poems. Lastly, this paper finds that the Tang poets may not strictly abide by the fore-mentioned regulation. Where there is a leeway in between, poets would write freely in terms of tone scheme.