It appears that [Chejahae] mystified the making of Hangeul in this way. The only comment that attracts our academic attention is the phrase, “but only from the accomplishment of right reason based on sound, i.e. according to the principles of sound.” The explanations of twenty eight letters in [Chejahae], in fact, support this strategy. This line of explanation shows that King Sejong relied upon the phonology developed in China for the principles of sound. It appears in various documents that King Sejong was good at Chinese phonology. Yet a careful reading leads us to believe that King Sejong was not satisfied with the past works, but he tried to perform his own new research. He developed a general phonological theory by adapting the Chinese phonological theory to the Korean language. This phonological theory at that time was the highest one with no parallel in history in either the Orient or the Occident. We can count the theory on syllable peak as the representative theory developed by King Sejong. As the Chinese phonology based on syllable dichotomy lacked even a concept of syllable peak itself, it is concluded that King Sejong established the theory of syllable peak for the first time.

It seems that a deep study of phonology made it possible for King Sejong to intend to invent an independent writing system. Here the graphemics can never be omitted in his study. China was a country of characters, and as a natural result, a science of graphemes developed on a high level. King Sejong accepted this scientific trend of graphemes and by extracting its core, he applied it to the making of new letters.

In a nutshell, the academic characteristic of King Sejong was to grasp all things in their fundamental nature, and Hangeul, as having been based on this, could become an original writing system. Of the many achievements in various areas, the invention of Hangeul was a brilliant pyramid which is to be imperishable in both our national and human cultural heritage.

No other name than ‘King Sejong’ appeared in the above discussion, and it is because the author believes that Hangeul was invented literally by him only. Not until the invention of Hangeul did some scholars including Shin Sok-Chu participate in the works related to Hangeul. The author already discussed this situation somewhat in detail in his paper, Lee Ki-Moon (1992, please refer to references). New material was later introduced by Lee Ka-Won (1994, please refer to references), and it is added here. Chongui-Kongju Yusa(貞懿公主遺事, An episode about Princess Chongoi) was recorded in [Chuksan Ahnssi Taedongbo](竹山安氏大同譜, a general family pedigree of Chuksan Ahn's), and of three articles the second article is as follows (translation from Chinese into Korean by Lee Ka-won):

世宗憫方言不能以文字相通 始製訓民正音 而變音吐着 猶未畢究 使諸大君解之 皆未能 遂下于公主 公主卽解究以進 世宗大加稱賞 特賜奴婢數百口. King Sejong felt very sorry that their language (Korean) could not communicate with Chinese characters, and he tried to invent Hunmin-Jeongeum(the Korean alphabetical system: It literally means ‘Right Sound for Teaching Subject.’) In the meantime, not having been able to solve all the alternate phenomena of sounds and the interpretation of the Chinese characters, he had all princes solve the problems. But they did not make it. At last he sent the problems down to princess Ch?ng?i. She immediately succeeded in it, and offered it for King Sejong. So he praised her greatly, and presented her with hundreds of slave families.

Princess Chongoi was the second daughter of King Sejong and was married to Mr. Ahn Maeng-Dam , a military officer in Yonch’ang province(延昌尉 安孟聃). And there was this valuable report in his family history. This is almost the only document which recorded the episodes during the making of Hangeul. It can be vividly seen from this record that King Sejong secretly proceeded with the invention of Hangeul, and when confronted with insoluble difficulties he consulted his nearest sons and daughters. It was pointed out that King Sejong had debated with his sons, including the prince in the present author's article (1992:7). This statement is based upon the following two facts: Firstly, King Sejong ordered his prince and his sons Suyang-Taegun and Anpyong-Taegun to arrange and organize the first work after inventing Hangeul, i.e. the translation of Chinese dictionary of phones.

Secondly, there appears in the prefaces of [Hongmuchong’un-Yok’un](洪武正韻譯訓, a translation and explanation of the Chinese phonetic philology [Hongmuchong’un]) and [Chik’hae-Tongjasop](直解童子習, the literal translation of the Chinese textbook for children [Tongjaspo) the statement that King Munjong, who had been a prince of King Sejong, helped his Father King Sejong with the invention of Hangeul. Now it is revealed that his princess also participated in the work of inventing Hangeul.