In the current work, studies have been pursued on Kana notaton of Chinese Characters of “Chinese Characters contained Final /t/” in Muromachi period, mainly focusing on “to’on” of “Bunmeiban Syubuninryaku(文明版 『聚分韻略』)” and “Ryakuin(略韻』)”, “Keichouban Syubuninryaku(慶長版 『聚分韻略』)”. Most of the main vowels were found to match with the basic main sounds in the to’on of Sansetsu and Sinsetsu.
The discrepancy in three rhyme texts was due to polyphonics and the changes of the central vowel.
Therefore, To’on is a little different in three rhyme Texts. But it can be concluded that there is a strong similarity between the On system of Kana Notation of Chinese Characters in three Rhyme Texts, and they are extremely close to each other in the system.