- Chronology: On June 25, 1950 North Korean forces crossed the 38th Parallel, (border separating North Korea and South Korea) with approximately 135,000 men. The Republic of Korea (ROK) Army contained 98,000 soldiers. On June 27, 1950, The United States joins the Korean War because they want to stop communism from spreading to South Korea. A few months later, in October, China joins the war to fight on the side of North Korea. China's army wins several important victories and pushes the US and South Korean troops back across the 38th Parallel. A peace talk begins in February 1951, with neither side gaining ground. It finally takes two years to come to an agreement, with the war dragging on. On July 27, 1953 North Korea and South Korea finally come to an agreement to stop the fighting. Even though Korea is still divided today, the countries agree to create a neutral zone called the Demilitarized Zone to separate the countries. </span>Chronology: On June 25, 1950 North Korean forces crossed the 38th Parallel, (border separating North Korea and South Korea) with approximately 135,000 men. The Republic of Korea (ROK) Army contained 98,000 soldiers. On June 27, 1950, The United States joins the Korean War because they want to stop communism from spreading to South Korea. A few months later, in October, China joins the war to fight on the side of North Korea. China's army wins several important victories and pushes the US and South Korean troops back across the 38th Parallel. A peace talk begins in February 1951, with neither side gaining ground. It finally takes two years to come to an agreement, with the war dragging on. On July 27, 1953 North Korea and South Korea finally come to an agreement to stop the fighting. Even though Korea is still divided today, the countries agree to create a neutral zone called the Demilitarized Zone to separate the countries.