<p>The Korean South Sea, referring to the southern shelf area of the Korean Peninsula, contains five rift basins: the Jeju, Ieodo, Geomun, Hansan, and Halla basins. This article provides an instructive manual for the stratigraphic chart made through 3 years of collaborative research between the Geological Society of Korea and Korea National Oil Corporation. The sedimentary succession of the Korean South Sea is divided into five chronostratigraphic series. The depositional ages of each series are constrained to the Paleocene, Eocene, Oligocene, Miocene, and post-Miocene, respectively, based mainly on biostratigraphic ages, together with the U-Pb ages of zircons and Ar-Ar isotope ages of the igneous rock. The chronostratigraphic series are subdivided into the stratigraphic units based on stratal termination patterns. The number of those units included in each chronostratigraphic series is varied among the rift basins. A systematic nomenclature for these stratigraphic sequences and their bounding surfaces was applied based on the timing of deposition. To create the stratigraphic chart, approximately 30,000 line-km of 2D and 500&#xa0;km² of 3D seismic reflection datasets acquired since the 1970s were examined with multiple absolute age proxies recovered from the offshore exploratory wells. The newly proposed stratigraphy is expected to provide a better understanding of the evolution of the rift basins and potential hydrocarbon system of the Korean South Sea.</p>