This is the country’s first book on standard rhymes composed of six volumes. It was published using type printing in 1448 (30th year of the reign of King Sejong) by scholars such as Sin Suk-ju, Choe Hang, and Bak Paeng-nyeon at the King’s instruction. Dongguk jeongun was compiled to set a standard way to write down Chinese characters in Korean. A similar attempt was made in China through the compilation of Hongwuzhenyun, a book on how Chinese characters should correctly read in Chinese. The book (19.8cm long and 31.9cm wide) is composed of the foreword (7 pages), contents (4 pages), Vol. 1 (46 pages), Vol. 2 (47 pages), Vol. 3 (46 pages), Vol. 4 (40 pages), Vol. 5 (43 pages), and Vol. 6 (44 pages). This book carries significance as the first attempt to write down Chinese characters in Korean. Experts speak highly of it as a material about research on national language, one as important as Hunminjeongeum. It is a basic material explaining how the letters of Hunminjeongeum (present-day Hangeul) were created and how its sound system is organized, serving as an important material for those studying the system of writing down the sound of Chinese characters in Korea.