Korean War Timeline By ScottE May 1, 1945 korea is divided at the 38th paralled by the us and su Jun 25, 1950 un/south korean troops cross the border into north korea Period: Aug 4, 1950 to Sep 18, 1950 battle of pusan perimeter Period: Sep 15, 1950 to Sep 19, 1950 battle in inchon Oct 1, 1950 china enters the korean war Oct 7, 1950 korean war begins north korean troops attack south korea Nov 1, 1950 chinese winter offensive Jul 27, 1953 cease fire is signed