Designations of the oceanic currents and their respective flow patterns in the Japanese archipelago. The Blue dotted arrow denotes the southern extremity of the First branch of the Oyashio current during its attenuation, while the Red dotted arrow demarcates the northern boundary of the Kuroshio Basin at that particular juncture. TC: Tsugaru Current, YSC: Yellow Sea Current, YSCC: Yellow Sea Counter Current, BP: Boso Peninsula.