A study on the vowel system of Hunminjeongeum in ‘Sildamjang’ of Jineonjip: In the connection of ‘The 27 Characters of Eonmunjamo’ and the vowels of Donggukjeongun

In the ‘Sildamjang’ from Jineonjip, the principles of notation corresponding to ‘Sildamja-Chinese translation-Hunminjeongeum’ are presented. What is unique about these principles is that Hunminjeongeum corresponds to four characters for each Sildamja and Chinese translation. The vowels of Hunminjeongeum are composed of ‘ㅏㆍㅓㅡ’ along with various complex vowels. When this method of vowel production and organization was applied to the vowels of ‘The 27 Characters of Eonmunjamo’, and the unmok (韻目) vowels in Donggukjeongun, it was found that while the production of vowels and their organization were the same, the arrangement differed. Each arrangement followed its own set of principles and could be explained by specific rules. Notably, the principle of yin (陰) and yang (陽) was applied to the arrangement of the unmok vowels in Donggukjeongun.