The western boundary current of the North Pacific subpolar gyre. Fed by the Alaskan Stream and Kamchatka Current, the Oyashio flows southward along the Kuril Islands and the east coast of northern Japan to 39°–40°N and occasionally as far south as 36°N. Near southern Hokkaido (43°N) the current splits into two branches known as the First and Second Oyashio Intrusion. In the region east of Tsugaru Strait (41°N) it is dominated by eddies; one or two cyclonic (warm core) eddies are formed each year. Every six years or so one of them grows into a giant eddy that then dominates the region for a year. Farther downstream the Oyashio meets the northward flowing Kuroshio to form the Arctic Polar Front. Both currents maintain their own frontal systems, the Oyashio Front being characterized by temperatures of 2°– 8°C and feeding into the Aleutian Current, while the Kuroshio Front has temperatures of 10°– 15°C and feeds into the North Pacific Current.