World Justice Project - Rule of Law Index - Country Profile for South Korea
Korealaw.com provides a detailed overview of Korean Legal System (open access).
Foreign Law Guide - South Korea (UniMelb staff & student access) provides access to legislation and other primary sources of law on multiple legal topics. It also contains bibliographies of useful secondary sources (books and articles) on these topics.
Korean legal system is a mix of civil and customary law. See Juriglobe for further information(open access).
Image courtesy of Juriglobe
See research guides on Korean legal research:
Law Library of Congress - Guides to Law Online