從“鶴膝”到“上尾”的概念錯置:杜甫律詩“四聲遞用”說獻疑

Misplaced Concepts from"Crane Knee"to"Upper Tail":an Argument on the"Four-tone Alternation Hypothesis" of Du Fu's Regulated Verses

在永明聲律向近體平仄律轉化的過程中,上尾和鶴膝既不像“平頭”一樣被納入平仄律系統,也未如“蜂腰”一樣逐漸淡出。近體詩的聲律規則基本已規避了上尾,到了清代,“上尾”轉而指代原本屬於鶴膝的病犯,這尤其表現在對杜甫律詩的討論中,即從“不犯上尾”到“四聲遞用”。通過對初盛唐及杜甫七律鶴膝情況的統計,發現杜甫律詩中並不存在顯著的“四聲遞用”,只是規避鶴膝的永明聲律傳統在當時的延續,而這一傳統在大曆詩歌中迹近消亡。大曆可以被看作平仄律代替永明律成馬標準格律的轉捩點。

During the transformation of Yongming meter system to Ping-ze meter system in the Tang Dynasty,as tone-related metrical violations,the"upper tail"and"crane knee"were neither incorporated into the Ping-ze system like“flat head",nor gradually faded out like"bee waist".The rules of the ending word of the line in regulated verses basically avoid violatingthe"upper tail”principle.In the Qing Dynasty,the term"upper tail"turned to refer to the metrical violation originally referring to"crane's knees",especially in the discussion of Du Fu's regulated poems:from“no violating upper tail"to“four-tone alternation".A statistic study on“crane knee"in Seven-syllable regulated verses from the early Tang to Du Fu,reveals that there is no significant"Four tones alternation"in Du Fu's regulated verses,but just the continuation of the early Tang metrical tradition of avoiding"crane knee",and this tradition almost reached the end in the era of Dali.Dali can be regarded as the turning point when the Ping-ze meter replaced the Yongming meter as the standard rule.The trajectory of the influence of the Yongming rhythm from its survival to its gradual withdrawal in the prosody system of the Tang dynasty can also help to return to the literary scene,free from the constraints of Qing poetic theory,and re-evaluate the exemplary significance of the Du poetry meter.