Hangul supremacy
Hangul supremacy is the belief, most widespread in Korea, that the Hangul alphabet developed by King Sejong the Great's Hall of Worthies in 1443 is the simplest, most logical, most beautiful and most scientific of the world's writing systems. In its extreme form, the belief holds that Hangul is in fact best suited for the expression of sounds in all languages.
Gari Ledyard
The "Hunmin Jeong-eum" credits the 古篆字 ""Gu" Seal Script" as being the source King Sejong or his ministers used to create hangul. This has traditionally been interpreted as the "Old" Seal Script, and has confused philologists because hangul bears no functional similarity to the Chinese seal scripts. However, 古 "gǔ" had more than one meaning: besides meaning "old", it could be used to refer to the Mongols (蒙古 "Měng-gǔ"). Records from Sejong's day played with this ambiguity, joking that "no one is more "gu" than the "Meng-gu"". That is, "Gu Seal Script" may have been a veiled reference to the Mongol Seal Script, or Phagspa alphabet. ("Seal script" is a style of writing, used for name seals and official stamps. Phagspa had a seal script variant modeled after the appearance of the Chinese seal script of its day. In this guise it was called the 蒙古篆字 Mongol Seal Script, with only the initial character distinguishing it from the 古篆字 credited by the "Hunmin Jeong-eum" as the source of hangul.) There were many Phagspa manuscripts in the Korean palace library, and several of Sejong's ministers knew the script well.