1948年,董同龢發表〈等韻門法通釋〉一文,區分《切韻》一系韻書與《四聲等子》、《切韻指掌圖》、《切韻指南》等「等韻門法」兩個範疇,強調了各自獨立的系統性特徵。很明顯,在他看來,似乎在《切韻》一系韻書演變過程中,各個時代的修訂者,並不受「等韻門法」意識的任何干擾和影響。但我們從《宋本廣韻》「新添類隔今更音和切」中卻看到了實實在在的等韻門法理論意識的「痕跡」,就使得董同龢的看法難以說得通。《宋本廣韻》「新添類隔今更音和切」貫徹的是唐末北宋時代等韻門法中的「音和」「正則」。以「音和」為正例的「正則」,而以「類隔」為變例的「變則」,使得與等韻門法無關的《切韻》一系韻書賦予了新的內涵,就是將之改造為「等韻化」了的《切韻》系韻書。後代,比如金韓道朝《五音集韻》等韻化韻書體例,尤其是明清兩代「韻書」與「韻圖」不分彼此,互為依托,互為補充的「等韻韻書」模式,是不是在這裡流露了新的「端倪」?從這個意義上講,宋代學者對《切韻》一系韻書的修訂,不是一個簡單化的「校讎」和「增損質正」工作,而是一個按照新的等韻意識審定,並建立新的等韻化韻書模式的脫胎換骨過程。這是前人認識並不到位的,應該予以說明。
Dong Tonghe published "The Interpretation of Dengyunmenfa (〈等韻門法通釋〉)" in 1948 to distinguish two different categories which include "a series of books about Qie Yun (《切韻》)" and "Si Sheng Deng Zi (四聲等子)", "Qie Yun Zhi Zhang Tu (切韻指掌圖)" and "Qie Yun Zhi Nan (切韻指南)". And in this article it also emphasizes their own independent systemic features. Obviously, in his view, it seems that in the process of the evolution of the rhyme book, the revisionists of the various ages are not disturbed and influenced by the consciousness of the rhyme method. However, We can see the consciousnesses of "Dengyunmenfa" (等韻門法) have really existed in the "Xintianleigejingengyinheqie" (新添類隔今更音和切) in Song Ben Guang Yun (《宋本廣韻》), that makes it hard for us to believe in the view of Dong Tonghe. The "Xintianleigejingengyinheqie" (新添類隔今更音和切) in Song Ben Guang Yun (《宋本廣韻》) reflects "Yinhe" (音和) and the regularity of "Dengyunmenfa" (等韻門法) in the time of the late Tang and Northern Song Dynasties. It takes "Yinhe" (音和) as a positive example of the "regular" and "Leige" (類隔) as a variant of the "change". Through this way it gives a new connotation to the "series of books about Qie Yun (《切韻》)". In other words, the books have transformed into the category of "Dengyun" (等韻). Han Daozhao' (living In Jing Dynasty) Wu Yin Ji Yun (五音集韻) is book of a style of "Dengyun" (等韻), and during the Ming and Qing Dynasties, "Rhyme Book" (韻書) and "Rhyme Map" (韻圖) relyed on each other, complemented each other, and finally formed the "Dengyun Rhyme Book (等韻韻書) mode". Isn't it reveal new clues? From this point of view, the revision of "series of books about Qieyun (《切韻》)" by scholars in Song Dynasty, is not only a simple "proofreading" and "gain quality", but also a new awareness of "Dengyun" which is in accordance with the examination and approval. And we can also regard it as a establishment of a new pattern of "Dengyun Rhyme Book mode". Predecessors have not recognized that, but now it should be explained.