The native alphabet of Korea, created at the court of King Sejong and promulgated in 1443–46 — one of the few writing systems ever deliberately designed rather than inherited, and built so its letters diagram the sounds they make. Dismissed for centuries by a Confucian elite who kept Chinese for serious writing, it was revived by nationalism and became the script of both Koreas after 1945; linguists rank it among the most systematically designed alphabets ever made.
Almost every alphabet on earth was inherited, not invented. The letters you are reading drifted across three thousand years out of older marks, each generation reshaping what it was handed. Hangul is a rare exception. In 1443 a Korean king's court sat down and designed a writing system deliberately, as a rational project, in a few years. And they built it cleverly. The consonant letters are tiny diagrams of the mouth: one shows the tongue touching the ridge behind the teeth, another the shape of the lips, another the open throat. The vowels are made from three marks for heaven, earth, and a standing person. Stronger sounds get extra strokes. In the famous claim, a wise person could learn it before the morning was over, and even a slow learner in ten days. Many linguists have praised it as one of the most systematic alphabets ever made.