Northern Limit Line mainland portion reverted to North Korean control, while the islands remained a part of South Korea despite their close proximity. The line extends into the sea from the Military Demarcation Line (MDL), and consists of straight line segments between 12 approximate channel midpoints, extended in an arc to prevent egress between both sides. On its western end the line extends out along the 38th parallel to the median line between Korea and China. The 1953 Armistice Agreement, which was signed by both North Korea and the United Nations Command (UNC), ended the Korean War and specified that the five islands
Canada in the Korean War in the objective that it had set with the United Nations forces. In April 1951, Chinese forces of the 118th Division attacked the Kapyong Valley in force, and pushed South Korean and New Zealand troops into retreat. Under heavy pressure, the Korean 6th Division broke, and the line collapsed. American and South Korean men poured through a gap under protective covering fire from Australians who were holding their section of the line despite heavy pressure. The 3rd Battalion, Royal Australian Regiment (3 RAR) and 2nd Battalion, Princess Patricia's Canadian Light Infantry (2 PPCLI) were ordered to halt this Chinese advance.