Hangul, the Korean writing system created in the fifteenth century, is renowned for its systematic relationship between letter shapes and sounds. Consonants iconically represent the shape of the vocal organs, and similar phonemes are depicted by corresponding letters. Vowels are also systematic, with their complexity reflecting the elaborateness of phonemes. This chapter explores Hangul’s systematicity through novel methods. By quantifying the relationship between letter shapes and sounds or grapho-phonemic systematicity, the research highlights Hangul’s purposeful design. Comparing it with other writing systems,the study further identifies three evolutionary lineages in conventional scripts. As a proof of concept, this research provides a valuable starting point for future interdisciplinary studies, aiming to unravel the dynamic between orthography, human cognition, and society.