There are two types of writing systems used today in Korea: one is a phonetic system called Han-gul,("the Korean script"), and the other is an ideographic system called
Hancha ("the Chinese characters"). The former is the native Korean writing system, while the latter is the writing system borrowed from Chinese. The modern Korean writing is done either exclusively in Han-gul or occasionally in a mixed writing, with
Hancha scattered here and there. But almost all public signs and billboards in Korea today use Han-gul exclusively.
Hangul is a phonetic-or phonemic if you will-writing system with relatively small number of letters: 25 altogether. It is traditionally held that there are 10 vowel symbols and 14 consonant symbols.
Roughly as the English letters are combined into words, the 24 letters in Korean are variously combined to form words-with some different rules of combination.
The direction of lines or rows of words has two ways: one is traditional and the other modern, as explained below. Both ways are equally common, but the modern style is gaining popularity.
a.) Traditional : Words are written TOP-TO-BOTTOM and lines proceed RIGHT-TO-LEFT (as in Chinese)
b.) Modern : Words are written LEFT-TO-RIGHT and lines proceed TOP-TO-BOTTOM (as in English)