North Korean patrol boats again moved across the water border off South Koreas west coast, and then turned around when confronted by South Korean warships. The North Koreans want the border, which was unofficially established along the 38th Parallel after the Korean War ended in 1953, moved south. This is because the west coast of Korea is a rich fishing area and the North needs the money. But the South refuses to agree to move the border and the North continues to press the matter with aggressive naval maneuvers across the invisible line in the water. The North has found that it's aggressive stance with nuclear weapons and ballistic missiles has brought billions of dollars in aid from South Korea, Japan and the United States. It apparently feels that aggressive behavior will pay off here as well.