Hangul syllable kuj

It spells Korean letter parts, not a fixed reaction.

Hangul syllables combine Korean letters called jamo: an initial consonant, a vowel, and sometimes a final consonant. Here they are ㅋ, ㅜ, and ㅈ. The Unicode label “Kuj” names that spelling structure; it is not a Korean dictionary gloss.

Hangul was created in 1443 and promulgated in 1446 under the name Hunminjeongeum (“Correct Sounds for the Instruction of the People”). It offered a more direct way to write Korean speech alongside systems based on Chinese characters. Early Hangul writing, called eonmun (“vernacular writing”), appeared in literature and private letters before the script also entered official documents. These dates describe Hangul’s history; they do not date the first use of this exact syllable.

Why can 쿶 appear in two stored forms?

Unicode stores it as one block or an equivalent letter sequence.

Normalization converts Hangul between those equivalent forms. When comparing exact text, normalize both strings first: they can look the same on screen while containing different code-point sequences.

A Korean IME, the keyboard software that assembles Hangul, can also move final ㅈ to the next syllable if the next input is a vowel.